diff --git a/backend/FwLite/FwLiteShared.Tests/Sync/SyncServiceTests.cs b/backend/FwLite/FwLiteShared.Tests/Sync/SyncServiceTests.cs
new file mode 100644
index 0000000000..7c90a3a14f
--- /dev/null
+++ b/backend/FwLite/FwLiteShared.Tests/Sync/SyncServiceTests.cs
@@ -0,0 +1,175 @@
+using System.Diagnostics.CodeAnalysis;
+using FwLiteShared.Sync;
+using LcmCrdt.Changes.Comments;
+using MiniLcm.Models;
+using SIL.Harmony;
+using SIL.Harmony.Changes;
+using SIL.Harmony.Core;
+
+namespace FwLiteShared.Tests.Sync;
+
+public class SyncServiceTests
+{
+    [Fact]
+    public void GetUnreadCommentsFromSyncResults_ReturnsCreatedUserComments()
+    {
+        var threadId = Guid.NewGuid();
+        var comment = new UserComment
+        {
+            Id = Guid.NewGuid(),
+            CommentThreadId = threadId,
+            Text = "synced comment"
+        };
+        var commentChange = new CreateUserCommentChange(comment);
+        var commitId = Guid.NewGuid();
+        var commit = new FakeCommit(commitId, new HybridDateTime(DateTimeOffset.UtcNow, 0))
+        {
+            ChangeEntities =
+            [
+                new ChangeEntity<IChange>
+                {
+                    Change = commentChange,
+                    CommitId = commitId,
+                    EntityId = commentChange.EntityId,
+                    Index = 0
+                },
+                new ChangeEntity<IChange>
+                {
+                    Change = new EditUserCommentChange(comment.Id, "edited", DateTimeOffset.UtcNow),
+                    CommitId = commitId,
+                    EntityId = comment.Id,
+                    Index = 1
+                }
+            ]
+        };
+
+        var results = new SyncResults([commit], [], true);
+
+        var unreadComments = SyncService.GetUnreadCommentsFromSyncResults(results, currentUserId: "current-user").ToArray();
+
+        unreadComments.Should().ContainSingle()
+            .Which.Should().Be((comment.Id, threadId));
+    }
+
+    [Fact]
+    public void GetUnreadCommentsFromSyncResults_ExcludesCommentsAuthoredByCurrentUser()
+    {
+        var threadId = Guid.NewGuid();
+        var mine = new CreateUserCommentChange(new UserComment
+        {
+            Id = Guid.NewGuid(),
+            CommentThreadId = threadId,
+            Text = "authored by me on another device",
+            AuthorId = "current-user"
+        });
+        var theirs = new CreateUserCommentChange(new UserComment
+        {
+            Id = Guid.NewGuid(),
+            CommentThreadId = threadId,
+            Text = "authored by someone else",
+            AuthorId = "other-user"
+        });
+        var commitId = Guid.NewGuid();
+        var commit = new FakeCommit(commitId, new HybridDateTime(DateTimeOffset.UtcNow, 0))
+        {
+            ChangeEntities =
+            [
+                new ChangeEntity<IChange> { Change = mine, CommitId = commitId, EntityId = mine.EntityId, Index = 0 },
+                new ChangeEntity<IChange> { Change = theirs, CommitId = commitId, EntityId = theirs.EntityId, Index = 1 }
+            ]
+        };
+
+        var results = new SyncResults([commit], [], true);
+
+        var unreadComments = SyncService.GetUnreadCommentsFromSyncResults(results, currentUserId: "current-user").ToArray();
+
+        unreadComments.Should().ContainSingle("comments authored by other users are unread, the current user's own are not")
+            .Which.Should().Be((theirs.EntityId, threadId));
+    }
+
+    [Fact]
+    public void GetUnreadCommentsFromSyncResults_WithoutCurrentUser_IncludesCommentWithNullAuthor()
+    {
+        var threadId = Guid.NewGuid();
+        var comment = new UserComment
+        {
+            Id = Guid.NewGuid(),
+            CommentThreadId = threadId,
+            Text = "synced comment with no author"
+        };
+        var change = new CreateUserCommentChange(comment);
+        var commitId = Guid.NewGuid();
+        var commit = new FakeCommit(commitId, new HybridDateTime(DateTimeOffset.UtcNow, 0))
+        {
+            ChangeEntities =
+            [
+                new ChangeEntity<IChange> { Change = change, CommitId = commitId, EntityId = change.EntityId, Index = 0 }
+            ]
+        };
+
+        var results = new SyncResults([commit], [], true);
+
+        var unreadComments = SyncService.GetUnreadCommentsFromSyncResults(results, currentUserId: null).ToArray();
+
+        unreadComments.Should().ContainSingle("with no current user, even an author-less synced comment is unread")
+            .Which.Should().Be((comment.Id, threadId));
+    }
+
+    [Fact]
+    public void GetDeletedCommentsFromSyncResults_ReturnsDeletedCommentsAndThreads()
+    {
+        var threadId = Guid.NewGuid();
+        var commentId = Guid.NewGuid();
+        var deletedThreadId = Guid.NewGuid();
+        var commitId = Guid.NewGuid();
+        var commit = new FakeCommit(commitId, new HybridDateTime(DateTimeOffset.UtcNow, 0))
+        {
+            ChangeEntities =
+            [
+                new ChangeEntity<IChange>
+                {
+                    Change = new DeleteChange<UserComment>(commentId),
+                    CommitId = commitId,
+                    EntityId = commentId,
+                    Index = 0
+                },
+                new ChangeEntity<IChange>
+                {
+                    Change = new DeleteChange<CommentThread>(deletedThreadId),
+                    CommitId = commitId,
+                    EntityId = deletedThreadId,
+                    Index = 1
+                },
+                new ChangeEntity<IChange>
+                {
+                    Change = new CreateUserCommentChange(new UserComment
+                    {
+                        Id = Guid.NewGuid(),
+                        CommentThreadId = threadId,
+                        Text = "still here"
+                    }),
+                    CommitId = commitId,
+                    EntityId = Guid.NewGuid(),
+                    Index = 2
+                }
+            ]
+        };
+
+        var results = new SyncResults([commit], [], true);
+
+        var (deletedCommentIds, deletedThreadIds) = SyncService.GetDeletedCommentsFromSyncResults(results);
+
+        deletedCommentIds.Should().ContainSingle().Which.Should().Be(commentId);
+        deletedThreadIds.Should().ContainSingle().Which.Should().Be(deletedThreadId);
+    }
+
+    private class FakeCommit : Commit
+    {
+        [SetsRequiredMembers]
+        public FakeCommit(Guid id, HybridDateTime hybridDateTime) : base(id, "", NullParentHash, hybridDateTime)
+        {
+            HybridDateTime = hybridDateTime;
+            SetParentHash(NullParentHash);
+        }
+    }
+}
diff --git a/backend/FwLite/FwLiteShared/Services/MiniLcmJsInvokable.cs b/backend/FwLite/FwLiteShared/Services/MiniLcmJsInvokable.cs
index a56aa4817e..a5fcfffb44 100644
--- a/backend/FwLite/FwLiteShared/Services/MiniLcmJsInvokable.cs
+++ b/backend/FwLite/FwLiteShared/Services/MiniLcmJsInvokable.cs
@@ -21,14 +21,14 @@ MiniLcmApiUserFacingWrappers userFacingWrappers
 {
     private readonly IMiniLcmApi _wrappedApi = userFacingWrappers.Apply(api, project, notificationWrapperFactory);
 
-    public record MiniLcmFeatures(bool? History, bool? Write, bool? OpenWithFlex, bool? Feedback, bool? Sync, bool? Audio, bool? CustomViews);
+    public record MiniLcmFeatures(bool? History, bool? Write, bool? OpenWithFlex, bool? Feedback, bool? Sync, bool? Audio, bool? CustomViews, bool? Comments);
     private bool SupportsSync => project.DataFormat == ProjectDataFormat.Harmony && api is CrdtMiniLcmApi;
     [JSInvokable]
     public MiniLcmFeatures SupportedFeatures()
     {
         var isCrdtProject = project.DataFormat == ProjectDataFormat.Harmony;
         var isFwDataProject = project.DataFormat == ProjectDataFormat.FwData;
-        return new(History: isCrdtProject, Write: CanWrite, OpenWithFlex: isFwDataProject, Feedback: true, Sync: SupportsSync, Audio: true, CustomViews: isCrdtProject);
+        return new(History: isCrdtProject, Write: CanWrite, OpenWithFlex: isFwDataProject, Feedback: true, Sync: SupportsSync, Audio: true, CustomViews: isCrdtProject, Comments: isCrdtProject);
     }
 
     private bool CanWrite =>
@@ -270,6 +270,114 @@ public async Task DeleteCustomView(Guid id)
         OnDataChanged();
     }
 
+    [JSInvokable]
+    public ValueTask<CommentThread[]> GetCommentThreads(SubjectType subjectType, Guid subjectId, bool includeComments = false)
+    {
+        return _wrappedApi.GetCommentThreads(subjectType, subjectId, includeComments).ToArrayAsync();
+    }
+
+    [JSInvokable]
+    [TsFunction(Type = "Promise<ICommentThread | null>")]
+    public Task<CommentThread?> GetCommentThread(Guid id)
+    {
+        return _wrappedApi.GetCommentThread(id);
+    }
+
+    [JSInvokable]
+    public ValueTask<UserComment[]> GetUserComments(Guid threadId)
+    {
+        return _wrappedApi.GetUserComments(threadId).ToArrayAsync();
+    }
+
+    [JSInvokable]
+    [TsFunction(Type = "Promise<IUserComment | null>")]
+    public Task<UserComment?> GetUserComment(Guid id)
+    {
+        return _wrappedApi.GetUserComment(id);
+    }
+
+    [JSInvokable]
+    public ValueTask<UserComment[]> GetUnreadComments(Guid? threadId = null)
+    {
+        return _wrappedApi.GetUnreadComments(threadId).ToArrayAsync();
+    }
+
+    [JSInvokable]
+    public ValueTask<UserComment[]> GetUnreadCommentsForSubject(SubjectType subjectType, Guid subjectId)
+    {
+        return _wrappedApi.GetUnreadCommentsForSubject(subjectType, subjectId).ToArrayAsync();
+    }
+
+    [JSInvokable]
+    public Task<int> CountUnreadComments(Guid? threadId = null)
+    {
+        return _wrappedApi.CountUnreadComments(threadId);
+    }
+
+    [JSInvokable]
+    public async Task<CommentThread> CreateCommentThread(CommentThread thread, UserComment firstComment)
+    {
+        var createdThread = await _wrappedApi.CreateCommentThread(thread, firstComment);
+        OnDataChanged();
+        return createdThread;
+    }
+
+    [JSInvokable]
+    public async Task<UserComment> AddUserComment(Guid threadId, UserComment comment)
+    {
+        var createdComment = await _wrappedApi.AddUserComment(threadId, comment);
+        OnDataChanged();
+        return createdComment;
+    }
+
+    [JSInvokable]
+    public async Task<UserComment> EditUserComment(Guid commentId, string text)
+    {
+        var updatedComment = await _wrappedApi.EditUserComment(commentId, text);
+        OnDataChanged();
+        return updatedComment;
+    }
+
+    [JSInvokable]
+    public async Task<CommentThread> SetCommentThreadStatus(Guid threadId, ThreadStatus status)
+    {
+        var updatedThread = await _wrappedApi.SetCommentThreadStatus(threadId, status);
+        OnDataChanged();
+        return updatedThread;
+    }
+
+    [JSInvokable]
+    public async Task DeleteUserComment(Guid commentId)
+    {
+        await _wrappedApi.DeleteUserComment(commentId);
+        OnDataChanged();
+    }
+
+    [JSInvokable]
+    public async Task DeleteCommentThread(Guid threadId)
+    {
+        await _wrappedApi.DeleteCommentThread(threadId);
+        OnDataChanged();
+    }
+
+    [JSInvokable]
+    public Task MarkCommentRead(Guid commentId)
+    {
+        return _wrappedApi.MarkCommentRead(commentId);
+    }
+
+    [JSInvokable]
+    public Task MarkCommentThreadRead(Guid threadId)
+    {
+        return _wrappedApi.MarkCommentThreadRead(threadId);
+    }
+
+    [JSInvokable]
+    public Task MarkAllCommentsRead()
+    {
+        return _wrappedApi.MarkAllCommentsRead();
+    }
+
     [JSInvokable]
     public async Task<Entry> CreateEntry(Entry entry, CreateEntryOptions options)
     {
diff --git a/backend/FwLite/FwLiteShared/Sync/SyncService.cs b/backend/FwLite/FwLiteShared/Sync/SyncService.cs
index f8501ecac3..e02da191a7 100644
--- a/backend/FwLite/FwLiteShared/Sync/SyncService.cs
+++ b/backend/FwLite/FwLiteShared/Sync/SyncService.cs
@@ -4,6 +4,7 @@
 using FwLiteShared.Services;
 using LexCore.Sync;
 using LcmCrdt;
+using LcmCrdt.Changes.Comments;
 using LcmCrdt.Data;
 using LcmCrdt.MediaServer;
 using LcmCrdt.RemoteSync;
@@ -28,7 +29,8 @@ public class SyncService(
     LcmMediaService lcmMediaService,
     IOptions<AuthConfig> authOptions,
     ILogger<SyncService> logger,
-    SyncRepository syncRepository)
+    SyncRepository syncRepository,
+    LocalCommentReadStatusService commentReadStatusService)
 {
     public async Task<SyncResults> SafeExecuteSync(bool skipNotifications = false)
     {
@@ -105,6 +107,7 @@ public async Task<SyncResults> ExecuteSync(bool skipNotifications = false)
             }
             logger.LogInformation("Synced project {ProjectName} with server", project.Name);
             UpdateSyncStatus(SyncStatus.Success);
+            await ApplySyncedCommentReadStatus(syncResults, project.LastUserId);
             await syncRepository.UpdateSyncDate(syncDate);
             // Best-effort: if the push listener failed to start at project-open (e.g. user was offline), this
             // restarts it now that we know auth + network are healthy. If it's already running, the cache
@@ -233,6 +236,37 @@ private async Task SendNotifications(SyncResults syncResults)
         }
     }
 
+    private async Task ApplySyncedCommentReadStatus(SyncResults syncResults, string? currentUserId)
+    {
+        await commentReadStatusService.MarkCommentsUnread(GetUnreadCommentsFromSyncResults(syncResults, currentUserId));
+        var (deletedCommentIds, deletedThreadIds) = GetDeletedCommentsFromSyncResults(syncResults);
+        await commentReadStatusService.RemoveUnreadComments(deletedCommentIds);
+        foreach (var threadId in deletedThreadIds)
+        {
+            await commentReadStatusService.MarkThreadRead(threadId);
+        }
+    }
+
+    public static IEnumerable<(Guid CommentId, Guid CommentThreadId)> GetUnreadCommentsFromSyncResults(SyncResults syncResults, string? currentUserId)
+    {
+        return syncResults.MissingFromLocal
+            .SelectMany(c => c.ChangeEntities, (_, change) => change.Change)
+            .OfType<CreateUserCommentChange>()
+            //with no current user (not signed in) nothing is "ours", so every synced comment is unread
+            .Where(change => currentUserId is null || change.AuthorId != currentUserId)
+            .Select(change => (CommentId: change.EntityId, change.CommentThreadId));
+    }
+
+    public static (IEnumerable<Guid> CommentIds, IEnumerable<Guid> ThreadIds) GetDeletedCommentsFromSyncResults(
+        SyncResults syncResults)
+    {
+        var changes = syncResults.MissingFromLocal
+            .SelectMany(c => c.ChangeEntities, (_, change) => change.Change);
+        var commentIds = changes.OfType<DeleteChange<UserComment>>().Select(change => change.EntityId);
+        var threadIds = changes.OfType<DeleteChange<CommentThread>>().Select(change => change.EntityId);
+        return (commentIds, threadIds);
+    }
+
     private async IAsyncEnumerable<Guid?> GetEntryId(IObjectWithId? entity)
     {
         switch (entity)
diff --git a/backend/FwLite/FwLiteShared/TypeGen/ReinforcedFwLiteTypingConfig.cs b/backend/FwLite/FwLiteShared/TypeGen/ReinforcedFwLiteTypingConfig.cs
index 7fbeef2a93..18bdb27bac 100644
--- a/backend/FwLite/FwLiteShared/TypeGen/ReinforcedFwLiteTypingConfig.cs
+++ b/backend/FwLite/FwLiteShared/TypeGen/ReinforcedFwLiteTypingConfig.cs
@@ -118,6 +118,8 @@ private static void ConfigureMiniLcmTypes(ConfigurationBuilder builder)
         builder.ExportAsEnum<WritingSystemType>();
         builder.ExportAsEnum<ReadFileResult>().UseString();
         builder.ExportAsEnum<UploadFileResult>().UseString();
+        builder.ExportAsEnum<ThreadStatus>().UseString();
+        builder.ExportAsEnum<SubjectType>().UseString();
         builder.ExportAsInterface<MiniLcmJsInvokable>()
             .FlattenHierarchy()
             .WithPublicProperties()
diff --git a/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.latest.verified.txt b/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.latest.verified.txt
index b28168b1ba..d9295d1c9a 100644
--- a/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.latest.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.latest.verified.txt
@@ -1293,5 +1293,58 @@
   {
     "$type": "SetMainPublicationChange",
     "EntityId": "c775e310-fc5c-6d01-5a02-146d579a88e5"
+  },
+  {
+    "$type": "CreateCommentThreadChange",
+    "SubjectId": "31bb6dfb-9987-6fd7-9ee3-92d6bce75611",
+    "SubjectType": "ExampleSentence",
+    "Status": "Closed",
+    "AuthorId": null,
+    "AuthorName": null,
+    "CreatedAt": "2026-07-01T17:07:13.0291493+07:00",
+    "UpdatedAt": "2026-07-02T07:20:03.8842896+07:00",
+    "EntityId": "ed481334-f9d2-ec59-fa0d-70d7dc2e2aa2"
+  },
+  {
+    "$type": "CreateCommentThreadChange",
+    "SubjectId": "1fc16c5c-ea2b-92b8-9af6-26404afcf856",
+    "SubjectType": "Unknown",
+    "Status": "Closed",
+    "AuthorId": "Licensed Steel Chicken",
+    "AuthorName": "Loop",
+    "CreatedAt": "2026-07-06T10:16:45.6785696+07:00",
+    "UpdatedAt": "2026-07-05T21:39:14.8355266+07:00",
+    "EntityId": "3381486c-2101-43ff-b508-82bd515eb950"
+  },
+  {
+    "$type": "CreateUserCommentChange",
+    "CommentThreadId": "a82b4c24-dec6-38c9-b69f-97b78457a395",
+    "PreviousCommentId": "4e472c9a-0274-ad6a-30a5-a89b27e221e0",
+    "Text": "composite",
+    "AuthorId": "Bolivar Fuerte",
+    "AuthorName": "Via",
+    "CreatedAt": "2026-07-01T21:49:53.1491117+07:00",
+    "UpdatedAt": "2026-07-02T02:56:57.3826486+07:00",
+    "EntityId": "1dadd431-cc82-d12c-8cc0-738cf0d15f09"
+  },
+  {
+    "$type": "EditUserCommentChange",
+    "Text": "Swiss Franc",
+    "UpdatedAt": "2026-07-01T19:07:09.8540119+07:00",
+    "EntityId": "41249114-1628-085e-fddd-a2afa9050490"
+  },
+  {
+    "$type": "SetCommentThreadStatusChange",
+    "Status": "Open",
+    "UpdatedAt": "2026-07-02T00:41:37.9431171+07:00",
+    "EntityId": "caab8a36-76c5-3ff7-1a98-593b697358c8"
+  },
+  {
+    "$type": "delete:CommentThread",
+    "EntityId": "5fd5cf80-bd5f-a0ad-e79c-4bfdb0973f9b"
+  },
+  {
+    "$type": "delete:UserComment",
+    "EntityId": "4be242d0-b1a6-986f-cc0d-b35860e69e60"
   }
 ]
\ No newline at end of file
diff --git a/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.legacy.verified.txt b/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.legacy.verified.txt
index 19edc4c876..f05a2d1748 100644
--- a/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.legacy.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/Changes/ChangeDeserializationRegressionData.legacy.verified.txt
@@ -625,5 +625,49 @@
       ],
       "EntityId": "f27a032b-e0f6-f389-b466-959bdb17086d"
     }
+  },
+  {
+    "Input": {
+      "$type": "CreateCommentThreadChange",
+      "SubjectId": "31bb6dfb-9987-6fd7-9ee3-92d6bce75611",
+      "SubjectType": "ExampleSentence",
+      "Status": "Closed",
+      "CreatedAt": "2026-07-01T17:07:13.0291493+07:00",
+      "UpdatedAt": "2026-07-02T07:20:03.8842896+07:00",
+      "EntityId": "ed481334-f9d2-ec59-fa0d-70d7dc2e2aa2"
+    },
+    "Output": {
+      "$type": "CreateCommentThreadChange",
+      "SubjectId": "31bb6dfb-9987-6fd7-9ee3-92d6bce75611",
+      "SubjectType": "ExampleSentence",
+      "Status": "Closed",
+      "AuthorId": null,
+      "AuthorName": null,
+      "CreatedAt": "2026-07-01T17:07:13.0291493+07:00",
+      "UpdatedAt": "2026-07-02T07:20:03.8842896+07:00",
+      "EntityId": "ed481334-f9d2-ec59-fa0d-70d7dc2e2aa2"
+    }
+  },
+  {
+    "Input": {
+      "$type": "CreateCommentThreadChange",
+      "SubjectId": "31bb6dfb-9987-6fd7-9ee3-92d6bce75611",
+      "SubjectType": "ExampleSentence",
+      "Status": "Closed",
+      "CreatedAt": "2026-07-01T17:07:13.0291493+07:00",
+      "UpdatedAt": "2026-07-02T07:20:03.8842896+07:00",
+      "EntityId": "ed481334-f9d2-ec59-fa0d-70d7dc2e2aa2"
+    },
+    "Output": {
+      "$type": "CreateCommentThreadChange",
+      "SubjectId": "31bb6dfb-9987-6fd7-9ee3-92d6bce75611",
+      "SubjectType": "ExampleSentence",
+      "Status": "Closed",
+      "AuthorId": null,
+      "AuthorName": null,
+      "CreatedAt": "2026-07-01T17:07:13.0291493+07:00",
+      "UpdatedAt": "2026-07-02T07:20:03.8842896+07:00",
+      "EntityId": "ed481334-f9d2-ec59-fa0d-70d7dc2e2aa2"
+    }
   }
 ]
\ No newline at end of file
diff --git a/backend/FwLite/LcmCrdt.Tests/Changes/UseChangesTests.cs b/backend/FwLite/LcmCrdt.Tests/Changes/UseChangesTests.cs
index 7b81d89da0..247ca900c3 100644
--- a/backend/FwLite/LcmCrdt.Tests/Changes/UseChangesTests.cs
+++ b/backend/FwLite/LcmCrdt.Tests/Changes/UseChangesTests.cs
@@ -3,6 +3,7 @@
 using Bogus;
 using FluentAssertions.Execution;
 using LcmCrdt.Changes;
+using LcmCrdt.Changes.Comments;
 using LcmCrdt.Changes.CustomJsonPatches;
 using LcmCrdt.Changes.Entries;
 using LcmCrdt.Changes.ExampleSentences;
@@ -316,5 +317,38 @@ customView with
                 Analysis = null
             });
         yield return new ChangeWithDependencies(editCustomViewChange, [createCustomViewChange]);
+
+        var commentThread = new CommentThread
+        {
+            Id = Guid.NewGuid(),
+            SubjectId = entry.Id,
+            SubjectType = SubjectType.Entry,
+            Status = ThreadStatus.Open,
+            AuthorId = "author-id",
+            AuthorName = "Author",
+            CreatedAt = DateTimeOffset.UtcNow,
+            UpdatedAt = DateTimeOffset.UtcNow
+        };
+        var createCommentThreadChange = new CreateCommentThreadChange(commentThread);
+        yield return new ChangeWithDependencies(createCommentThreadChange, [createEntryChange]);
+
+        var userComment = new UserComment
+        {
+            Id = Guid.NewGuid(),
+            CommentThreadId = commentThread.Id,
+            Text = "Test comment",
+            AuthorId = "author-id",
+            AuthorName = "Author",
+            CreatedAt = DateTimeOffset.UtcNow,
+            UpdatedAt = DateTimeOffset.UtcNow
+        };
+        var createUserCommentChange = new CreateUserCommentChange(userComment);
+        yield return new ChangeWithDependencies(createUserCommentChange, [createCommentThreadChange]);
+
+        var editUserCommentChange = new EditUserCommentChange(userComment.Id, "Updated comment", DateTimeOffset.UtcNow);
+        yield return new ChangeWithDependencies(editUserCommentChange, [createUserCommentChange]);
+
+        var closeCommentThreadChange = new SetCommentThreadStatusChange(commentThread.Id, ThreadStatus.Closed, DateTimeOffset.UtcNow);
+        yield return new ChangeWithDependencies(closeCommentThreadChange, [createCommentThreadChange]);
     }
 }
diff --git a/backend/FwLite/LcmCrdt.Tests/ConfigRegistrationTests.cs b/backend/FwLite/LcmCrdt.Tests/ConfigRegistrationTests.cs
index de8092deca..ecc27e0cef 100644
--- a/backend/FwLite/LcmCrdt.Tests/ConfigRegistrationTests.cs
+++ b/backend/FwLite/LcmCrdt.Tests/ConfigRegistrationTests.cs
@@ -15,6 +15,8 @@ public class ConfigRegistrationTests
         typeof(JsonPatchChange<RemoteResource>), //not supported
         typeof(JsonPatchChange<ExampleSentence>), //replaced by JsonPatchExampleSentenceChange
         typeof(JsonPatchChange<CustomView>), //not supported. Use EditCustomViewChange
+        typeof(JsonPatchChange<CommentThread>), //not supported. Use SetCommentThreadStatusChange
+        typeof(JsonPatchChange<UserComment>), //not supported. Use EditUserCommentChange
         typeof(DeleteChange<MorphType>), //MorphTypes cannot be deleted
     ];
 
diff --git a/backend/FwLite/LcmCrdt.Tests/Data/BaseSerializationTest.cs b/backend/FwLite/LcmCrdt.Tests/Data/BaseSerializationTest.cs
index 93d2eda5a4..520a70bb73 100644
--- a/backend/FwLite/LcmCrdt.Tests/Data/BaseSerializationTest.cs
+++ b/backend/FwLite/LcmCrdt.Tests/Data/BaseSerializationTest.cs
@@ -4,6 +4,7 @@
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using LcmCrdt.Changes;
+using MiniLcm.Models;
 using MiniLcm.Tests.AutoFakerHelpers;
 using Soenneker.Utils.AutoBogus;
 using Soenneker.Utils.AutoBogus.Config;
@@ -64,6 +65,14 @@ private static AutoFakerConfig GetAutoFakerConfig()
                     }
                     morphType.Id = canonical.Id;
                 }
+            }, true),
+            new SimpleOverride<CommentThread>(context =>
+            {
+                if (context.Instance is CommentThread thread && thread.Comments is { Count: > 0 })
+                {
+                    foreach (var comment in thread.Comments)
+                        comment.CommentThreadId = thread.Id;
+                }
             }, true)
         );
         return config;
diff --git a/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.latest.verified.txt b/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.latest.verified.txt
index b7e45c5eb4..da0cb7652f 100644
--- a/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.latest.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.latest.verified.txt
@@ -3935,5 +3935,159 @@
     },
     "Id": "edd0c7a1-e37c-c67b-7522-eed5ec86fde8",
     "DeletedAt": null
+  },
+  {
+    "$type": "MiniLcmCrdtAdapter",
+    "Obj": {
+      "$type": "CommentThread",
+      "Id": "8f911a35-f5c5-f686-4ae7-51edce857df1",
+      "DeletedAt": null,
+      "SubjectId": "53b9eb28-12b0-2840-eaf2-7fc58c40a185",
+      "SubjectType": "Sense",
+      "Status": "Open",
+      "AuthorId": null,
+      "AuthorName": null,
+      "CreatedAt": "2026-07-02T09:46:27.5880032+07:00",
+      "UpdatedAt": "2026-07-02T04:31:08.1939565+07:00",
+      "Comments": [
+        {
+          "Id": "3f947d22-70e0-d30d-62c5-2b50f0ad7030",
+          "DeletedAt": null,
+          "CommentThreadId": "b0f6e6fe-e118-26b7-b286-9db69a140309",
+          "PreviousCommentId": "dfcc8e8c-2ec6-c2d4-a794-53a5a5915b50",
+          "Text": "microchip",
+          "AuthorId": "bus",
+          "AuthorName": "Saint Helena Pound",
+          "CreatedAt": "2026-07-01T18:18:32.8141612+07:00",
+          "UpdatedAt": "2026-07-02T11:46:28.7172532+07:00"
+        }
+      ]
+    },
+    "Id": "8f911a35-f5c5-f686-4ae7-51edce857df1",
+    "DeletedAt": null
+  },
+  {
+    "$type": "MiniLcmCrdtAdapter",
+    "Obj": {
+      "$type": "CommentThread",
+      "Id": "e1e30272-9a49-2644-eef3-f36caa061eae",
+      "DeletedAt": null,
+      "SubjectId": "bbd65c4d-2448-6222-a207-d301428d881d",
+      "SubjectType": "ExampleSentence",
+      "Status": "Closed",
+      "AuthorId": "back-end",
+      "AuthorName": "Fantastic Rubber Tuna",
+      "CreatedAt": "2026-07-05T12:17:02.0060498+07:00",
+      "UpdatedAt": "2026-07-06T04:04:55.5381107+07:00",
+      "Comments": [
+        {
+          "Id": "33961abf-15c1-71b8-ff24-be0bd5987b6f",
+          "DeletedAt": null,
+          "CommentThreadId": "e1e30272-9a49-2644-eef3-f36caa061eae",
+          "PreviousCommentId": "6f6d1c85-1d21-3659-a8be-234ba476d167",
+          "Text": "Awesome Soft Hat",
+          "AuthorId": "Strategist",
+          "AuthorName": "redundant",
+          "CreatedAt": "2026-07-05T17:15:38.2078204+07:00",
+          "UpdatedAt": "2026-07-06T00:23:27.650184+07:00"
+        }
+      ]
+    },
+    "Id": "e1e30272-9a49-2644-eef3-f36caa061eae",
+    "DeletedAt": null
+  },
+  {
+    "$type": "MiniLcmCrdtAdapter",
+    "Obj": {
+      "$type": "UserComment",
+      "Id": "85ef40c2-e168-7cdd-e302-d3edc18c38a5",
+      "DeletedAt": null,
+      "CommentThreadId": "bcea6bb9-1378-e3cd-b9d0-7c87b2ae9968",
+      "PreviousCommentId": "b87d624d-9827-4172-0beb-7d1f2d8e028c",
+      "Text": "target",
+      "AuthorId": "strategy",
+      "AuthorName": "Internal",
+      "CreatedAt": "2026-07-02T14:57:23.0439447+07:00",
+      "UpdatedAt": "2026-07-02T12:32:51.0578643+07:00"
+    },
+    "Id": "85ef40c2-e168-7cdd-e302-d3edc18c38a5",
+    "DeletedAt": null
+  },
+  {
+    "$type": "MiniLcmCrdtAdapter",
+    "Obj": {
+      "$type": "CommentThread",
+      "Id": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+      "DeletedAt": null,
+      "SubjectId": "8f24e142-5373-8369-f828-417b81833e27",
+      "SubjectType": "Entry",
+      "Status": "Open",
+      "AuthorId": null,
+      "AuthorName": null,
+      "CreatedAt": "2026-07-03T04:57:05.9016384+07:00",
+      "UpdatedAt": "2026-07-03T16:30:59.5749065+07:00",
+      "Comments": [
+        {
+          "Id": "39408d18-4d46-a112-78eb-24c7c00d8d12",
+          "DeletedAt": null,
+          "CommentThreadId": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+          "PreviousCommentId": "b8099120-2b7c-5e86-da14-f5ab0e1b4bcd",
+          "Text": "Lek",
+          "AuthorId": "Cross-platform",
+          "AuthorName": "Functionality",
+          "CreatedAt": "2026-07-02T23:31:01.4636808+07:00",
+          "UpdatedAt": "2026-07-03T03:11:05.4871024+07:00"
+        }
+      ]
+    },
+    "Id": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+    "DeletedAt": null
+  },
+  {
+    "$type": "MiniLcmCrdtAdapter",
+    "Obj": {
+      "$type": "CommentThread",
+      "Id": "2afa7c96-656a-536d-705f-b7a60a64bed2",
+      "DeletedAt": null,
+      "SubjectId": "2fac2398-0791-6c39-9d6e-fae54133d59f",
+      "SubjectType": "ExampleSentence",
+      "Status": "Open",
+      "AuthorId": "Frozen",
+      "AuthorName": "Handcrafted Soft Chips",
+      "CreatedAt": "2026-07-06T10:31:41.0420447+07:00",
+      "UpdatedAt": "2026-07-05T13:20:51.1147632+07:00",
+      "Comments": [
+        {
+          "Id": "c830a70c-ae94-2b3f-6994-cc17334649df",
+          "DeletedAt": null,
+          "CommentThreadId": "2afa7c96-656a-536d-705f-b7a60a64bed2",
+          "PreviousCommentId": "040ce2bb-b5e4-e532-8f65-5f25062e79fb",
+          "Text": "withdrawal",
+          "AuthorId": "Human",
+          "AuthorName": "Island",
+          "CreatedAt": "2026-07-06T02:54:36.0758935+07:00",
+          "UpdatedAt": "2026-07-05T23:32:25.6629513+07:00"
+        }
+      ]
+    },
+    "Id": "2afa7c96-656a-536d-705f-b7a60a64bed2",
+    "DeletedAt": null
+  },
+  {
+    "$type": "MiniLcmCrdtAdapter",
+    "Obj": {
+      "$type": "UserComment",
+      "Id": "4f5808a8-bbf1-e23d-e5fe-5a997f13bf3a",
+      "DeletedAt": null,
+      "CommentThreadId": "fdff5d2b-4405-84fa-40b9-bfa2c1302828",
+      "PreviousCommentId": "1e01381d-2b48-63f5-bc31-99710cea2695",
+      "Text": "Phased",
+      "AuthorId": "driver",
+      "AuthorName": "Home Loan Account",
+      "CreatedAt": "2026-07-02T22:19:48.4007941+07:00",
+      "UpdatedAt": "2026-07-03T13:54:23.9312531+07:00"
+    },
+    "Id": "4f5808a8-bbf1-e23d-e5fe-5a997f13bf3a",
+    "DeletedAt": null
   }
 ]
\ No newline at end of file
diff --git a/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.legacy.verified.txt b/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.legacy.verified.txt
index a3fe21d28d..625c969cc8 100644
--- a/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.legacy.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationRegressionData.legacy.verified.txt
@@ -3900,5 +3900,125 @@
       "Id": "853b91e6-d738-7d5d-cc98-e62904160c35",
       "DeletedAt": null
     }
+  },
+  {
+    "Input": {
+      "$type": "MiniLcmCrdtAdapter",
+      "Obj": {
+        "$type": "CommentThread",
+        "Id": "8f911a35-f5c5-f686-4ae7-51edce857df1",
+        "DeletedAt": null,
+        "SubjectId": "53b9eb28-12b0-2840-eaf2-7fc58c40a185",
+        "SubjectType": "Sense",
+        "Status": "Open",
+        "CreatedAt": "2026-07-02T09:46:27.5880032+07:00",
+        "UpdatedAt": "2026-07-02T04:31:08.1939565+07:00",
+        "Comments": [
+          {
+            "Id": "3f947d22-70e0-d30d-62c5-2b50f0ad7030",
+            "DeletedAt": null,
+            "CommentThreadId": "b0f6e6fe-e118-26b7-b286-9db69a140309",
+            "PreviousCommentId": "dfcc8e8c-2ec6-c2d4-a794-53a5a5915b50",
+            "Text": "microchip",
+            "AuthorId": "bus",
+            "AuthorName": "Saint Helena Pound",
+            "CreatedAt": "2026-07-01T18:18:32.8141612+07:00",
+            "UpdatedAt": "2026-07-02T11:46:28.7172532+07:00"
+          }
+        ]
+      },
+      "Id": "8f911a35-f5c5-f686-4ae7-51edce857df1",
+      "DeletedAt": null
+    },
+    "Output": {
+      "$type": "MiniLcmCrdtAdapter",
+      "Obj": {
+        "$type": "CommentThread",
+        "Id": "8f911a35-f5c5-f686-4ae7-51edce857df1",
+        "DeletedAt": null,
+        "SubjectId": "53b9eb28-12b0-2840-eaf2-7fc58c40a185",
+        "SubjectType": "Sense",
+        "Status": "Open",
+        "AuthorId": null,
+        "AuthorName": null,
+        "CreatedAt": "2026-07-02T09:46:27.5880032+07:00",
+        "UpdatedAt": "2026-07-02T04:31:08.1939565+07:00",
+        "Comments": [
+          {
+            "Id": "3f947d22-70e0-d30d-62c5-2b50f0ad7030",
+            "DeletedAt": null,
+            "CommentThreadId": "b0f6e6fe-e118-26b7-b286-9db69a140309",
+            "PreviousCommentId": "dfcc8e8c-2ec6-c2d4-a794-53a5a5915b50",
+            "Text": "microchip",
+            "AuthorId": "bus",
+            "AuthorName": "Saint Helena Pound",
+            "CreatedAt": "2026-07-01T18:18:32.8141612+07:00",
+            "UpdatedAt": "2026-07-02T11:46:28.7172532+07:00"
+          }
+        ]
+      },
+      "Id": "8f911a35-f5c5-f686-4ae7-51edce857df1",
+      "DeletedAt": null
+    }
+  },
+  {
+    "Input": {
+      "$type": "MiniLcmCrdtAdapter",
+      "Obj": {
+        "$type": "CommentThread",
+        "Id": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+        "DeletedAt": null,
+        "SubjectId": "8f24e142-5373-8369-f828-417b81833e27",
+        "SubjectType": "Entry",
+        "Status": "Open",
+        "CreatedAt": "2026-07-03T04:57:05.9016384+07:00",
+        "UpdatedAt": "2026-07-03T16:30:59.5749065+07:00",
+        "Comments": [
+          {
+            "Id": "39408d18-4d46-a112-78eb-24c7c00d8d12",
+            "DeletedAt": null,
+            "CommentThreadId": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+            "PreviousCommentId": "b8099120-2b7c-5e86-da14-f5ab0e1b4bcd",
+            "Text": "Lek",
+            "AuthorId": "Cross-platform",
+            "AuthorName": "Functionality",
+            "CreatedAt": "2026-07-02T23:31:01.4636808+07:00",
+            "UpdatedAt": "2026-07-03T03:11:05.4871024+07:00"
+          }
+        ]
+      },
+      "Id": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+      "DeletedAt": null
+    },
+    "Output": {
+      "$type": "MiniLcmCrdtAdapter",
+      "Obj": {
+        "$type": "CommentThread",
+        "Id": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+        "DeletedAt": null,
+        "SubjectId": "8f24e142-5373-8369-f828-417b81833e27",
+        "SubjectType": "Entry",
+        "Status": "Open",
+        "AuthorId": null,
+        "AuthorName": null,
+        "CreatedAt": "2026-07-03T04:57:05.9016384+07:00",
+        "UpdatedAt": "2026-07-03T16:30:59.5749065+07:00",
+        "Comments": [
+          {
+            "Id": "39408d18-4d46-a112-78eb-24c7c00d8d12",
+            "DeletedAt": null,
+            "CommentThreadId": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+            "PreviousCommentId": "b8099120-2b7c-5e86-da14-f5ab0e1b4bcd",
+            "Text": "Lek",
+            "AuthorId": "Cross-platform",
+            "AuthorName": "Functionality",
+            "CreatedAt": "2026-07-02T23:31:01.4636808+07:00",
+            "UpdatedAt": "2026-07-03T03:11:05.4871024+07:00"
+          }
+        ]
+      },
+      "Id": "b14e4cf6-2b50-74a4-e21e-482b38efd849",
+      "DeletedAt": null
+    }
   }
 ]
\ No newline at end of file
diff --git a/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationTests.cs b/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationTests.cs
index e6ee0f894a..efb93edb3d 100644
--- a/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationTests.cs
+++ b/backend/FwLite/LcmCrdt.Tests/Data/SnapshotDeserializationTests.cs
@@ -37,6 +37,21 @@ private static IObjectBase GenerateSnapshotForType(Type type)
         }
     }
 
+    [Fact]
+    public void AutoFaker_GeneratedCommentThread_CommentsHaveMatchingThreadId()
+    {
+        for (var i = 0; i < 20; i++)
+        {
+            var thread = Faker.Generate<CommentThread>();
+            if (thread.Comments is not { Count: > 0 }) continue;
+
+            thread.Comments.Should().OnlyContain(comment => comment.CommentThreadId == thread.Id);
+            return;
+        }
+
+        throw new Exception("AutoFaker did not generate a CommentThread with comments after 20 attempts");
+    }
+
     [Fact]
     public void CanDeserializeProjectDumpRegressionData()
     {
diff --git a/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyChangeModels.verified.txt b/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyChangeModels.verified.txt
index f11904f409..4d9da1f85e 100644
--- a/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyChangeModels.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyChangeModels.verified.txt
@@ -220,6 +220,30 @@
       DerivedType: DeleteChange<CustomView>,
       TypeDiscriminator: delete:CustomView
     },
+    {
+      DerivedType: CreateCommentThreadChange,
+      TypeDiscriminator: CreateCommentThreadChange
+    },
+    {
+      DerivedType: CreateUserCommentChange,
+      TypeDiscriminator: CreateUserCommentChange
+    },
+    {
+      DerivedType: EditUserCommentChange,
+      TypeDiscriminator: EditUserCommentChange
+    },
+    {
+      DerivedType: SetCommentThreadStatusChange,
+      TypeDiscriminator: SetCommentThreadStatusChange
+    },
+    {
+      DerivedType: DeleteChange<CommentThread>,
+      TypeDiscriminator: delete:CommentThread
+    },
+    {
+      DerivedType: DeleteChange<UserComment>,
+      TypeDiscriminator: delete:UserComment
+    },
     {
       DerivedType: CreateMorphTypeChange,
       TypeDiscriminator: CreateMorphTypeChange
diff --git a/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyDbModel.verified.txt b/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyDbModel.verified.txt
index 6eaccd9213..d17e1227f1 100644
--- a/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyDbModel.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyDbModel.verified.txt
@@ -1,4 +1,20 @@
 Model: 
+  EntityType: UnreadComment
+    Properties: 
+      CommentId (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
+      CommentThreadId (Guid) Required Index
+      MarkedUnreadAt (DateTimeOffset) Required
+    Keys: 
+      CommentId PK
+    Indexes: 
+      CommentThreadId
+    Annotations: 
+      Relational:FunctionName: 
+      Relational:Schema: 
+      Relational:SqlQuery: 
+      Relational:TableName: UnreadComments
+      Relational:ViewName: 
+      Relational:ViewSchema: 
   EntityType: EntrySearchRecord
     Properties: 
       Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
@@ -38,6 +54,35 @@
       Relational:TableName: ProjectData
       Relational:ViewName: 
       Relational:ViewSchema: 
+  EntityType: CommentThread
+    Properties: 
+      Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
+      AuthorId (string)
+      AuthorName (string)
+      CreatedAt (DateTimeOffset) Required Index
+      DeletedAt (DateTimeOffset?)
+      SnapshotId (no field, Guid?) Shadow FK Index
+      Status (ThreadStatus) Required
+      SubjectId (Guid) Required Index
+      SubjectType (SubjectType) Required Index
+      UpdatedAt (DateTimeOffset) Required
+    Navigations: 
+      Comments (List<UserComment>) Collection ToDependent UserComment
+    Keys: 
+      Id PK
+    Foreign keys: 
+      CommentThread {'SnapshotId'} -> ObjectSnapshot {'Id'} Unique SetNull
+    Indexes: 
+      CreatedAt
+      SnapshotId Unique
+      SubjectType, SubjectId
+    Annotations: 
+      Relational:FunctionName: 
+      Relational:Schema: 
+      Relational:SqlQuery: 
+      Relational:TableName: CommentThread
+      Relational:ViewName: 
+      Relational:ViewSchema: 
   EntityType: ComplexFormComponent
     Properties: 
       Id (_id, Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
@@ -344,6 +389,34 @@
       Relational:TableName: Sense
       Relational:ViewName: 
       Relational:ViewSchema: 
+  EntityType: UserComment
+    Properties: 
+      Id (Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
+      AuthorId (string)
+      AuthorName (string)
+      CommentThreadId (Guid) Required FK Index
+      CreatedAt (DateTimeOffset) Required Index
+      DeletedAt (DateTimeOffset?)
+      PreviousCommentId (Guid?)
+      SnapshotId (no field, Guid?) Shadow FK Index
+      Text (string) Required
+      UpdatedAt (DateTimeOffset) Required
+    Keys: 
+      Id PK
+    Foreign keys: 
+      UserComment {'CommentThreadId'} -> CommentThread {'Id'} Required Cascade ToDependent: Comments
+      UserComment {'SnapshotId'} -> ObjectSnapshot {'Id'} Unique SetNull
+    Indexes: 
+      CommentThreadId
+      CreatedAt
+      SnapshotId Unique
+    Annotations: 
+      Relational:FunctionName: 
+      Relational:Schema: 
+      Relational:SqlQuery: 
+      Relational:TableName: UserComment
+      Relational:ViewName: 
+      Relational:ViewSchema: 
   EntityType: WritingSystem
     Properties: 
       Id (_id, Guid) Required PK AfterSave:Throw ValueGenerated.OnAdd
diff --git a/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyIObjectWithIdModels.verified.txt b/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyIObjectWithIdModels.verified.txt
index 048b425e86..c94eb71fdf 100644
--- a/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyIObjectWithIdModels.verified.txt
+++ b/backend/FwLite/LcmCrdt.Tests/DataModelSnapshotTests.VerifyIObjectWithIdModels.verified.txt
@@ -40,6 +40,14 @@
       DerivedType: CustomView,
       TypeDiscriminator: CustomView
     },
+    {
+      DerivedType: CommentThread,
+      TypeDiscriminator: CommentThread
+    },
+    {
+      DerivedType: UserComment,
+      TypeDiscriminator: UserComment
+    },
     {
       DerivedType: MorphType,
       TypeDiscriminator: MorphType
diff --git a/backend/FwLite/LcmCrdt.Tests/MiniLcmTests/CommentTests.cs b/backend/FwLite/LcmCrdt.Tests/MiniLcmTests/CommentTests.cs
new file mode 100644
index 0000000000..963dc74176
--- /dev/null
+++ b/backend/FwLite/LcmCrdt.Tests/MiniLcmTests/CommentTests.cs
@@ -0,0 +1,480 @@
+using FluentValidation;
+using LcmCrdt.Data;
+using Microsoft.EntityFrameworkCore;
+
+namespace LcmCrdt.Tests.MiniLcmTests;
+
+public class CommentTests(MiniLcmApiFixture fixture) : IClassFixture<MiniLcmApiFixture>
+{
+    private async Task SetCurrentUser(string userId, string? name = null)
+    {
+        var projectService = fixture.GetService<CurrentProjectService>();
+        await projectService.UpdateLastUser(name ?? userId, userId);
+        await projectService.UpdateUserRole(UserProjectRole.Editor);
+    }
+
+    private Task MarkCommentsUnread(params UserComment[] comments)
+    {
+        var readStatusService = fixture.GetService<LocalCommentReadStatusService>();
+        return readStatusService.MarkCommentsUnread(comments.Select(comment => (comment.Id, comment.CommentThreadId)));
+    }
+
+    private Task ClearUnreadComments()
+    {
+        return fixture.Api.MarkAllCommentsRead();
+    }
+
+    private async Task ClearLastUserId()
+    {
+        await fixture.DbContext.ProjectData.ExecuteUpdateAsync(calls => calls
+            .SetProperty(p => p.LastUserId, (string?)null)
+            .SetProperty(p => p.LastUserName, (string?)null));
+        await fixture.GetService<CurrentProjectService>().RefreshProjectData();
+    }
+
+    private static CommentThread NewThread(SubjectType subjectType = SubjectType.Entry, Guid? subjectId = null)
+    {
+        return new CommentThread
+        {
+            Id = Guid.NewGuid(),
+            SubjectType = subjectType,
+            SubjectId = subjectId ?? Guid.NewGuid()
+        };
+    }
+
+    private static UserComment NewComment(string text = "Comment", Guid? id = null)
+    {
+        return new UserComment
+        {
+            Id = id ?? Guid.NewGuid(),
+            Text = text
+        };
+    }
+
+    private async Task<(CommentThread Thread, UserComment FirstComment)> CreateThreadWithComment(
+        string authorId,
+        SubjectType subjectType = SubjectType.Entry,
+        Guid? subjectId = null,
+        string text = "First")
+    {
+        await SetCurrentUser(authorId);
+        var thread = await fixture.Api.CreateCommentThread(NewThread(subjectType, subjectId), NewComment(text));
+        var firstComment = (await fixture.Api.GetUserComments(thread.Id).ToArrayAsync()).Single();
+        return (thread, firstComment);
+    }
+
+    [Fact]
+    public async Task CreateThreadWithFirstComment_PopulatesAuthorAndTimestamps()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await SetCurrentUser(authorId, "Author Name");
+
+        var thread = await fixture.Api.CreateCommentThread(NewThread(), NewComment("hello"));
+        var comments = await fixture.Api.GetUserComments(thread.Id).ToArrayAsync();
+
+        thread.Status.Should().Be(ThreadStatus.Open);
+        thread.CreatedAt.Should().NotBe(default);
+        thread.AuthorId.Should().Be(authorId);
+        thread.AuthorName.Should().Be("Author Name");
+        comments.Should().ContainSingle();
+        comments[0].Text.Should().Be("hello");
+        comments[0].AuthorId.Should().Be(authorId);
+        comments[0].AuthorName.Should().Be("Author Name");
+        comments[0].CreatedAt.Should().NotBe(default);
+    }
+
+    [Fact]
+    public async Task CreateThreadWithFirstComment_ThreadAndCommentShareAuthor()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await SetCurrentUser(authorId, "Thread Author");
+
+        var thread = await fixture.Api.CreateCommentThread(NewThread(), NewComment("hello"));
+        var reloaded = await fixture.Api.GetCommentThread(thread.Id);
+
+        reloaded.Should().NotBeNull();
+        reloaded!.AuthorId.Should().Be(authorId);
+        reloaded.AuthorName.Should().Be("Thread Author");
+    }
+
+    [Fact]
+    public async Task RepliesEditStatusAndDeleteComment_Work()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        var (thread, firstComment) = await CreateThreadWithComment(authorId);
+
+        var reply = await fixture.Api.AddUserComment(thread.Id, NewComment("reply") with
+        {
+            PreviousCommentId = firstComment.Id
+        });
+        var edited = await fixture.Api.EditUserComment(reply.Id, "edited reply");
+        var closed = await fixture.Api.SetCommentThreadStatus(thread.Id, ThreadStatus.Closed);
+        await fixture.Api.DeleteUserComment(reply.Id);
+
+        edited.Text.Should().Be("edited reply");
+        edited.UpdatedAt.Should().BeAfter(edited.CreatedAt);
+        closed.Status.Should().Be(ThreadStatus.Closed);
+        var remaining = await fixture.Api.GetUserComments(thread.Id).ToArrayAsync();
+        remaining.Should().ContainSingle(c => c.Id == firstComment.Id);
+    }
+
+    [Fact]
+    public async Task GetCommentThreads_CanIncludeComments()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        var subjectId = Guid.NewGuid();
+        var (thread, firstComment) = await CreateThreadWithComment(authorId, SubjectType.Entry, subjectId);
+        var reply = await fixture.Api.AddUserComment(thread.Id, NewComment("reply") with
+        {
+            PreviousCommentId = firstComment.Id
+        });
+        var (_, otherComment) = await CreateThreadWithComment(authorId, SubjectType.Entry, Guid.NewGuid(), "other");
+
+        var withoutComments = await fixture.Api.GetCommentThreads(SubjectType.Entry, subjectId).ToArrayAsync();
+        var withComments = await fixture.Api.GetCommentThreads(SubjectType.Entry, subjectId, includeComments: true).ToArrayAsync();
+
+        withoutComments.Should().ContainSingle();
+        withoutComments[0].Comments.Should().BeNull();
+        withComments.Should().ContainSingle();
+        var includedComments = withComments[0].Comments;
+        includedComments.Should().NotBeNull();
+        includedComments!.Should().Contain(c => c.Id == firstComment.Id);
+        includedComments.Should().Contain(c => c.Id == reply.Id);
+        includedComments.Should().NotContain(c => c.Id == otherComment.Id);
+    }
+
+    [Fact]
+    public async Task DeleteThread_CascadesToComments()
+    {
+        var (thread, _) = await CreateThreadWithComment($"author-{Guid.NewGuid()}");
+        await fixture.Api.AddUserComment(thread.Id, NewComment("reply"));
+
+        await fixture.Api.DeleteCommentThread(thread.Id);
+
+        (await fixture.Api.GetCommentThread(thread.Id)).Should().BeNull();
+        (await fixture.Api.GetUserComments(thread.Id).ToArrayAsync()).Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task DeletingParentEntry_DoesNotDeleteThreadOrComments()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await SetCurrentUser(authorId);
+        var entry = await fixture.Api.CreateEntry(new Entry
+        {
+            Id = Guid.NewGuid(),
+            LexemeForm = { { "en", "commented entry" } }
+        });
+        var (thread, firstComment) = await CreateThreadWithComment(authorId, SubjectType.Entry, entry.Id);
+
+        await fixture.Api.DeleteEntry(entry.Id);
+
+        (await fixture.Api.GetCommentThread(thread.Id)).Should().NotBeNull();
+        (await fixture.Api.GetUserComment(firstComment.Id)).Should().NotBeNull();
+    }
+
+    [Fact]
+    public async Task CanCreateThreadForAlreadyDeletedSubject()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await SetCurrentUser(authorId);
+        var entry = await fixture.Api.CreateEntry(new Entry
+        {
+            Id = Guid.NewGuid(),
+            LexemeForm = { { "en", "deleted entry" } }
+        });
+        await fixture.Api.DeleteEntry(entry.Id);
+
+        var thread = await fixture.Api.CreateCommentThread(NewThread(SubjectType.Entry, entry.Id), NewComment("after delete"));
+
+        thread.SubjectId.Should().Be(entry.Id);
+        (await fixture.Api.GetUserComments(thread.Id).ToArrayAsync()).Should().ContainSingle();
+    }
+
+    [Fact]
+    public async Task ClosedThread_AllowsRepliesAndUnreadTracking()
+    {
+        var firstAuthor = $"author-{Guid.NewGuid()}";
+        var secondAuthor = $"author-{Guid.NewGuid()}";
+        var (thread, _) = await CreateThreadWithComment(firstAuthor);
+        await fixture.Api.SetCommentThreadStatus(thread.Id, ThreadStatus.Closed);
+
+        await SetCurrentUser(secondAuthor);
+        var reply = await fixture.Api.AddUserComment(thread.Id, NewComment("late reply"));
+        await MarkCommentsUnread(reply);
+
+        await SetCurrentUser(firstAuthor);
+        var comments = await fixture.Api.GetUserComments(thread.Id).ToArrayAsync();
+        var unread = await fixture.Api.GetUnreadComments(thread.Id).ToArrayAsync();
+
+        comments.Should().Contain(c => c.Id == reply.Id);
+        unread.Should().ContainSingle(c => c.Id == reply.Id);
+    }
+
+    [Fact]
+    public async Task SupportsAllSubjectTypes()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        foreach (var subjectType in Enum.GetValues<SubjectType>())
+        {
+            var thread = await CreateThreadWithComment(authorId, subjectType, Guid.NewGuid(), subjectType.ToString());
+            thread.Thread.SubjectType.Should().Be(subjectType);
+        }
+    }
+
+    [Fact]
+    public async Task OnlyAuthorCanEditOrDeleteComment()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        var otherUserId = $"other-{Guid.NewGuid()}";
+        var (_, firstComment) = await CreateThreadWithComment(authorId);
+
+        await SetCurrentUser(otherUserId);
+
+        await Assert.ThrowsAsync<UnauthorizedAccessException>(() => fixture.Api.EditUserComment(firstComment.Id, "not allowed"));
+        await Assert.ThrowsAsync<UnauthorizedAccessException>(() => fixture.Api.DeleteUserComment(firstComment.Id));
+    }
+
+    [Fact]
+    public async Task ReadStatus_CanMarkOneThreadAndAll()
+    {
+        var readerId = $"reader-{Guid.NewGuid()}";
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (thread1, firstComment1) = await CreateThreadWithComment(authorId);
+        var reply1 = await fixture.Api.AddUserComment(thread1.Id, NewComment("reply 1"));
+        var (thread2, firstComment2) = await CreateThreadWithComment(authorId);
+        await MarkCommentsUnread(firstComment1, reply1, firstComment2);
+
+        await SetCurrentUser(readerId);
+        (await fixture.Api.CountUnreadComments()).Should().Be(3);
+
+        await fixture.Api.MarkCommentRead(firstComment1.Id);
+        (await fixture.Api.CountUnreadComments()).Should().Be(2);
+        (await fixture.Api.CountUnreadComments(thread1.Id)).Should().Be(1);
+
+        await fixture.Api.MarkCommentThreadRead(thread1.Id);
+        (await fixture.Api.CountUnreadComments()).Should().Be(1);
+        (await fixture.Api.GetUnreadComments().ToArrayAsync()).Should().ContainSingle(c => c.Id == firstComment2.Id);
+        (await fixture.Api.CountUnreadComments(thread2.Id)).Should().Be(1);
+
+        await fixture.Api.MarkAllCommentsRead();
+        (await fixture.Api.CountUnreadComments()).Should().Be(0);
+        (await fixture.Api.GetUnreadComments().ToArrayAsync()).Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task ReadStatus_CanGetUnreadCommentsBySubject()
+    {
+        var readerId = $"reader-{Guid.NewGuid()}";
+        var authorId = $"author-{Guid.NewGuid()}";
+        var subjectId = Guid.NewGuid();
+        await ClearUnreadComments();
+        var (_, firstComment) = await CreateThreadWithComment(authorId, SubjectType.Entry, subjectId, "target 1");
+        var (_, secondComment) = await CreateThreadWithComment(authorId, SubjectType.Entry, subjectId, "target 2");
+        var (_, otherSubjectComment) = await CreateThreadWithComment(authorId, SubjectType.Entry, Guid.NewGuid(), "other subject");
+        var (_, otherTypeComment) = await CreateThreadWithComment(authorId, SubjectType.Sense, subjectId, "other type");
+        await MarkCommentsUnread(firstComment, secondComment, otherSubjectComment, otherTypeComment);
+
+        await SetCurrentUser(readerId);
+        var unread = await fixture.Api.GetUnreadCommentsForSubject(SubjectType.Entry, subjectId).ToArrayAsync();
+
+        unread.Should().HaveCount(2);
+        unread.Should().Contain(c => c.Id == firstComment.Id);
+        unread.Should().Contain(c => c.Id == secondComment.Id);
+        unread.Should().NotContain(c => c.Id == otherSubjectComment.Id);
+        unread.Should().NotContain(c => c.Id == otherTypeComment.Id);
+    }
+
+    [Fact]
+    public async Task ReadStatus_IsLocalNotPerUser()
+    {
+        var reader1 = $"reader-{Guid.NewGuid()}";
+        var reader2 = $"reader-{Guid.NewGuid()}";
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (_, firstComment) = await CreateThreadWithComment(authorId);
+        await MarkCommentsUnread(firstComment);
+
+        await SetCurrentUser(reader1);
+        await fixture.Api.MarkCommentRead(firstComment.Id);
+
+        await SetCurrentUser(reader2);
+        (await fixture.Api.GetUnreadComments().ToArrayAsync()).Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task MarkCommentsUnread_ConcurrentDuplicate_DoesNotThrowAndLeavesSingleRow()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (thread, firstComment) = await CreateThreadWithComment(authorId);
+        var readStatusService = fixture.GetService<LocalCommentReadStatusService>();
+        var commentRef = (firstComment.Id, firstComment.CommentThreadId);
+
+        var tasks = Enumerable.Range(0, 10)
+            .Select(_ => readStatusService.MarkCommentsUnread([commentRef]))
+            .ToArray();
+
+        await Task.WhenAll(tasks);
+
+        fixture.DbContext.UnreadComments.Count(c => c.CommentId == firstComment.Id).Should().Be(1);
+        (await readStatusService.CountUnreadComments(thread.Id)).Should().Be(1);
+    }
+
+    [Fact]
+    public async Task MarkCommentsUnread_BatchWithPartialDuplicate_InsertsRemainingNewComments()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (_, comment1) = await CreateThreadWithComment(authorId, text: "one");
+        var (_, comment2) = await CreateThreadWithComment(authorId, text: "two");
+        var (_, comment3) = await CreateThreadWithComment(authorId, text: "three");
+        var readStatusService = fixture.GetService<LocalCommentReadStatusService>();
+        var batch = new[]
+        {
+            (comment1.Id, comment1.CommentThreadId),
+            (comment2.Id, comment2.CommentThreadId),
+            (comment3.Id, comment3.CommentThreadId)
+        };
+
+        await Task.WhenAll(
+            readStatusService.MarkCommentsUnread(batch),
+            readStatusService.MarkCommentsUnread([(comment1.Id, comment1.CommentThreadId)]));
+
+        (await readStatusService.CountUnreadComments()).Should().Be(3);
+        fixture.DbContext.UnreadComments.Select(c => c.CommentId)
+            .Should().BeEquivalentTo([comment1.Id, comment2.Id, comment3.Id]);
+    }
+
+    [Fact]
+    public async Task CreateCommentThread_WithoutLastUserId_ThrowsValidationException()
+    {
+        await ClearLastUserId();
+
+        var act = () => fixture.Api.CreateCommentThread(NewThread(), NewComment("hello"));
+
+        await act.Should().ThrowAsync<ValidationException>()
+            .WithMessage("*known user identity*");
+    }
+
+    [Fact]
+    public async Task AddUserComment_WithoutLastUserId_ThrowsValidationException()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        var (thread, _) = await CreateThreadWithComment(authorId);
+        await ClearLastUserId();
+
+        var act = () => fixture.Api.AddUserComment(thread.Id, NewComment("reply"));
+
+        await act.Should().ThrowAsync<ValidationException>()
+            .WithMessage("*known user identity*");
+    }
+
+    [Fact]
+    public async Task ReadStatus_IncomingCommentsBecomeUnreadAndMarkingIsIdempotent()
+    {
+        var readerId = $"reader-{Guid.NewGuid()}";
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (thread, _) = await CreateThreadWithComment(authorId);
+
+        await SetCurrentUser(authorId);
+        var comment = await fixture.Api.AddUserComment(thread.Id, NewComment("arrived later"));
+        await MarkCommentsUnread(comment);
+        await MarkCommentsUnread(comment);
+
+        await SetCurrentUser(readerId);
+        (await fixture.Api.GetUnreadComments(thread.Id).ToArrayAsync()).Should().ContainSingle(c => c.Id == comment.Id);
+
+        await fixture.Api.MarkCommentRead(comment.Id);
+        await fixture.Api.MarkCommentRead(comment.Id);
+
+        (await fixture.Api.GetUnreadComments(thread.Id).ToArrayAsync()).Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task ReadStatus_LocalCreatedCommentsStartRead()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (thread, firstComment) = await CreateThreadWithComment(authorId);
+        await fixture.Api.AddUserComment(thread.Id, NewComment("reply"));
+
+        (await fixture.Api.GetUnreadComments().ToArrayAsync()).Should().BeEmpty();
+        fixture.DbContext.UnreadComments.Should().BeEmpty();
+        (await fixture.Api.GetUserComment(firstComment.Id)).Should().NotBeNull();
+    }
+
+    [Fact]
+    public async Task GetCommentThreads_CommentsAreSortedChronologically()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await SetCurrentUser(authorId);
+        var subjectId = Guid.NewGuid();
+        var baseTime = DateTimeOffset.UtcNow.AddHours(-5);
+        var threadId = Guid.NewGuid();
+        var firstCommentId = Guid.NewGuid();
+        var secondCommentId = Guid.NewGuid();
+        var thirdCommentId = Guid.NewGuid();
+
+        await fixture.Api.CreateCommentThread(
+            NewThread(SubjectType.Entry, subjectId) with { Id = threadId },
+            NewComment("first") with
+            {
+                Id = firstCommentId,
+                CreatedAt = baseTime,
+                UpdatedAt = baseTime
+            });
+        await fixture.Api.AddUserComment(threadId, NewComment("third") with
+        {
+            Id = thirdCommentId,
+            CreatedAt = baseTime.AddHours(2),
+            UpdatedAt = baseTime.AddHours(2)
+        });
+        await fixture.Api.AddUserComment(threadId, NewComment("second") with
+        {
+            Id = secondCommentId,
+            CreatedAt = baseTime.AddHours(1),
+            UpdatedAt = baseTime.AddHours(1)
+        });
+
+        var thread = (await fixture.Api.GetCommentThreads(SubjectType.Entry, subjectId, includeComments: true)
+            .ToArrayAsync()).Single();
+        var commentIds = thread.Comments!.Select(c => c.Id).ToArray();
+
+        commentIds.Should().Equal([firstCommentId, secondCommentId, thirdCommentId]);
+    }
+
+    [Fact]
+    public async Task ReadStatus_DeletedThreadRemovesUnreadRows()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (thread, firstComment) = await CreateThreadWithComment(authorId);
+        var reply = await fixture.Api.AddUserComment(thread.Id, NewComment("reply"));
+        await MarkCommentsUnread(firstComment, reply);
+        (await fixture.Api.CountUnreadComments(thread.Id)).Should().Be(2);
+
+        await fixture.Api.DeleteCommentThread(thread.Id);
+
+        (await fixture.Api.GetUnreadComments(thread.Id).ToArrayAsync()).Should().BeEmpty();
+        (await fixture.Api.CountUnreadComments(thread.Id)).Should().Be(0);
+        fixture.DbContext.UnreadComments.Where(c => c.CommentThreadId == thread.Id).Should().BeEmpty();
+    }
+
+    [Fact]
+    public async Task ReadStatus_DeletedUnreadCommentsDoNotInflateUnreadResults()
+    {
+        var authorId = $"author-{Guid.NewGuid()}";
+        await ClearUnreadComments();
+        var (thread, firstComment) = await CreateThreadWithComment(authorId);
+        await MarkCommentsUnread(firstComment);
+        (await fixture.Api.CountUnreadComments(thread.Id)).Should().Be(1);
+
+        await fixture.Api.DeleteUserComment(firstComment.Id);
+
+        (await fixture.Api.GetUnreadComments(thread.Id).ToArrayAsync()).Should().BeEmpty();
+        (await fixture.Api.CountUnreadComments(thread.Id)).Should().Be(0);
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Changes/Comments/CreateCommentThreadChange.cs b/backend/FwLite/LcmCrdt/Changes/Comments/CreateCommentThreadChange.cs
new file mode 100644
index 0000000000..7c5378c139
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Changes/Comments/CreateCommentThreadChange.cs
@@ -0,0 +1,52 @@
+using System.Text.Json.Serialization;
+using SIL.Harmony;
+using SIL.Harmony.Changes;
+using SIL.Harmony.Core;
+using SIL.Harmony.Entities;
+
+namespace LcmCrdt.Changes.Comments;
+
+public class CreateCommentThreadChange : CreateChange<CommentThread>, ISelfNamedType<CreateCommentThreadChange>
+{
+    public CreateCommentThreadChange(CommentThread thread) : base(thread.Id == Guid.Empty ? Guid.NewGuid() : thread.Id)
+    {
+        thread.Id = EntityId;
+        SubjectId = thread.SubjectId;
+        SubjectType = thread.SubjectType;
+        Status = thread.Status;
+        AuthorId = thread.AuthorId;
+        AuthorName = thread.AuthorName;
+        CreatedAt = thread.CreatedAt == default ? DateTimeOffset.UtcNow : thread.CreatedAt;
+        UpdatedAt = thread.UpdatedAt == default ? CreatedAt : thread.UpdatedAt;
+    }
+
+    [JsonConstructor]
+    private CreateCommentThreadChange(Guid entityId, Guid subjectId, SubjectType subjectType) : base(entityId)
+    {
+        SubjectId = subjectId;
+        SubjectType = subjectType;
+    }
+
+    public Guid SubjectId { get; init; }
+    public SubjectType SubjectType { get; init; }
+    public ThreadStatus Status { get; set; }
+    public string? AuthorId { get; set; }
+    public string? AuthorName { get; set; }
+    public DateTimeOffset CreatedAt { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+
+    public override ValueTask<CommentThread> NewEntity(Commit commit, IChangeContext context)
+    {
+        return ValueTask.FromResult(new CommentThread
+        {
+            Id = EntityId,
+            SubjectId = SubjectId,
+            SubjectType = SubjectType,
+            Status = Status,
+            AuthorId = AuthorId,
+            AuthorName = AuthorName,
+            CreatedAt = CreatedAt,
+            UpdatedAt = UpdatedAt
+        });
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Changes/Comments/CreateUserCommentChange.cs b/backend/FwLite/LcmCrdt/Changes/Comments/CreateUserCommentChange.cs
new file mode 100644
index 0000000000..63d1f983d1
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Changes/Comments/CreateUserCommentChange.cs
@@ -0,0 +1,53 @@
+using System.Text.Json.Serialization;
+using SIL.Harmony;
+using SIL.Harmony.Changes;
+using SIL.Harmony.Core;
+using SIL.Harmony.Entities;
+
+namespace LcmCrdt.Changes.Comments;
+
+public class CreateUserCommentChange : CreateChange<UserComment>, ISelfNamedType<CreateUserCommentChange>
+{
+    public CreateUserCommentChange(UserComment comment) : base(comment.Id == Guid.Empty ? Guid.NewGuid() : comment.Id)
+    {
+        comment.Id = EntityId;
+        CommentThreadId = comment.CommentThreadId;
+        PreviousCommentId = comment.PreviousCommentId;
+        Text = comment.Text;
+        AuthorId = comment.AuthorId;
+        AuthorName = comment.AuthorName;
+        CreatedAt = comment.CreatedAt == default ? DateTimeOffset.UtcNow : comment.CreatedAt;
+        UpdatedAt = comment.UpdatedAt == default ? CreatedAt : comment.UpdatedAt;
+    }
+
+    [JsonConstructor]
+    private CreateUserCommentChange(Guid entityId, Guid commentThreadId, string text) : base(entityId)
+    {
+        CommentThreadId = commentThreadId;
+        Text = text;
+    }
+
+    public Guid CommentThreadId { get; init; }
+    public Guid? PreviousCommentId { get; set; }
+    public string Text { get; set; }
+    public string? AuthorId { get; set; }
+    public string? AuthorName { get; set; }
+    public DateTimeOffset CreatedAt { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+
+    public override async ValueTask<UserComment> NewEntity(Commit commit, IChangeContext context)
+    {
+        return new UserComment
+        {
+            Id = EntityId,
+            CommentThreadId = CommentThreadId,
+            PreviousCommentId = PreviousCommentId,
+            Text = Text,
+            AuthorId = AuthorId,
+            AuthorName = AuthorName,
+            CreatedAt = CreatedAt,
+            UpdatedAt = UpdatedAt,
+            DeletedAt = await context.IsObjectDeleted(CommentThreadId) ? commit.DateTime : null
+        };
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Changes/Comments/EditUserCommentChange.cs b/backend/FwLite/LcmCrdt/Changes/Comments/EditUserCommentChange.cs
new file mode 100644
index 0000000000..5a9738617a
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Changes/Comments/EditUserCommentChange.cs
@@ -0,0 +1,31 @@
+using System.Text.Json.Serialization;
+using SIL.Harmony.Changes;
+using SIL.Harmony.Core;
+using SIL.Harmony.Entities;
+
+namespace LcmCrdt.Changes.Comments;
+
+public class EditUserCommentChange : EditChange<UserComment>, ISelfNamedType<EditUserCommentChange>
+{
+    public EditUserCommentChange(Guid entityId, string text, DateTimeOffset updatedAt) : base(entityId)
+    {
+        Text = text;
+        UpdatedAt = updatedAt;
+    }
+
+    [JsonConstructor]
+    private EditUserCommentChange(Guid entityId, string text) : base(entityId)
+    {
+        Text = text;
+    }
+
+    public string Text { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+
+    public override ValueTask ApplyChange(UserComment entity, IChangeContext context)
+    {
+        entity.Text = Text;
+        entity.UpdatedAt = UpdatedAt;
+        return ValueTask.CompletedTask;
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Changes/Comments/SetCommentThreadStatusChange.cs b/backend/FwLite/LcmCrdt/Changes/Comments/SetCommentThreadStatusChange.cs
new file mode 100644
index 0000000000..fe1b26ab77
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Changes/Comments/SetCommentThreadStatusChange.cs
@@ -0,0 +1,31 @@
+using System.Text.Json.Serialization;
+using SIL.Harmony.Changes;
+using SIL.Harmony.Core;
+using SIL.Harmony.Entities;
+
+namespace LcmCrdt.Changes.Comments;
+
+public class SetCommentThreadStatusChange : EditChange<CommentThread>, ISelfNamedType<SetCommentThreadStatusChange>
+{
+    public SetCommentThreadStatusChange(Guid entityId, ThreadStatus status, DateTimeOffset updatedAt) : base(entityId)
+    {
+        Status = status;
+        UpdatedAt = updatedAt;
+    }
+
+    [JsonConstructor]
+    private SetCommentThreadStatusChange(Guid entityId, ThreadStatus status) : base(entityId)
+    {
+        Status = status;
+    }
+
+    public ThreadStatus Status { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+
+    public override ValueTask ApplyChange(CommentThread entity, IChangeContext context)
+    {
+        entity.Status = Status;
+        entity.UpdatedAt = UpdatedAt;
+        return ValueTask.CompletedTask;
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/CrdtMiniLcmApi.cs b/backend/FwLite/LcmCrdt/CrdtMiniLcmApi.cs
index 1aa48ada4a..72e3f85cc8 100644
--- a/backend/FwLite/LcmCrdt/CrdtMiniLcmApi.cs
+++ b/backend/FwLite/LcmCrdt/CrdtMiniLcmApi.cs
@@ -1,7 +1,9 @@
 using System.Data;
+using FluentValidation;
 using SIL.Harmony;
 using SIL.Harmony.Changes;
 using LcmCrdt.Changes;
+using LcmCrdt.Changes.Comments;
 using LcmCrdt.Changes.CustomJsonPatches;
 using LcmCrdt.Changes.Entries;
 using LcmCrdt.Changes.ExampleSentences;
@@ -30,6 +32,7 @@ public class CrdtMiniLcmApi(
     IOptions<LcmCrdtConfig> config,
     ILogger<CrdtMiniLcmApi> logger,
     LcmMediaService lcmMediaService,
+    LocalCommentReadStatusService commentReadStatusService,
     CommitMetadataInterceptor commitMetadataInterceptor,
     EntrySearchService? entrySearchService = null) : IMiniLcmApi
 {
@@ -1065,6 +1068,174 @@ private void AssertManagerRoleForCustomViewWrite()
             $"Only managers can manage custom views.");
     }
 
+    public async IAsyncEnumerable<CommentThread> GetCommentThreads(SubjectType subjectType, Guid subjectId, bool includeComments = false)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        var threads = repo.CommentThreads
+            .Where(t => t.SubjectType == subjectType && t.SubjectId == subjectId);
+        if (includeComments)
+        {
+            threads = Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.Include(threads, t => t.Comments!.OrderBy(c => c.CreatedAt).ThenBy(c => c.Id));
+        }
+
+        threads = threads.OrderBy(t => t.CreatedAt).ThenBy(t => t.Id);
+        await foreach (var thread in threads.AsAsyncEnumerable())
+        {
+            yield return thread;
+        }
+    }
+
+    public async Task<CommentThread?> GetCommentThread(Guid id)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        return await repo.GetCommentThread(id);
+    }
+
+    public async IAsyncEnumerable<UserComment> GetUserComments(Guid threadId)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        var comments = repo.UserComments
+            .Where(c => c.CommentThreadId == threadId)
+            .OrderBy(c => c.CreatedAt).ThenBy(c => c.Id);
+        await foreach (var comment in comments.AsAsyncEnumerable())
+        {
+            yield return comment;
+        }
+    }
+
+    public async Task<UserComment?> GetUserComment(Guid id)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        return await repo.GetUserComment(id);
+    }
+
+    public async IAsyncEnumerable<UserComment> GetUnreadComments(Guid? threadId = null)
+    {
+        foreach (var comment in await commentReadStatusService.GetUnreadComments(threadId))
+        {
+            yield return comment;
+        }
+    }
+
+    public async IAsyncEnumerable<UserComment> GetUnreadCommentsForSubject(SubjectType subjectType, Guid subjectId)
+    {
+        foreach (var comment in await commentReadStatusService.GetUnreadCommentsForSubject(subjectType, subjectId))
+        {
+            yield return comment;
+        }
+    }
+
+    public Task<int> CountUnreadComments(Guid? threadId = null)
+    {
+        return commentReadStatusService.CountUnreadComments(threadId);
+    }
+
+    public async Task<CommentThread> CreateCommentThread(CommentThread thread, UserComment firstComment)
+    {
+        if (thread.Id == Guid.Empty) thread.Id = Guid.NewGuid();
+        var now = DateTimeOffset.UtcNow;
+        StampCommentThreadAuthor(thread, now);
+        firstComment.CommentThreadId = thread.Id;
+        StampCommentAuthor(firstComment, now);
+
+        await AddChanges([
+            new CreateCommentThreadChange(thread),
+            new CreateUserCommentChange(firstComment)
+        ]);
+        return await GetCommentThread(thread.Id) ?? throw NotFoundException.ForType<CommentThread>(thread.Id);
+    }
+
+    public async Task<UserComment> AddUserComment(Guid threadId, UserComment comment)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        _ = await repo.GetCommentThread(threadId) ?? throw NotFoundException.ForType<CommentThread>(threadId);
+        comment.CommentThreadId = threadId;
+        StampCommentAuthor(comment, DateTimeOffset.UtcNow);
+
+        await AddChange(new CreateUserCommentChange(comment));
+        return await repo.GetUserComment(comment.Id) ?? throw NotFoundException.ForType<UserComment>(comment.Id);
+    }
+
+    public async Task<UserComment> EditUserComment(Guid commentId, string text)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        var comment = await repo.GetUserComment(commentId) ?? throw NotFoundException.ForType<UserComment>(commentId);
+        AssertCurrentUserCanChangeComment(comment);
+        await AddChange(new EditUserCommentChange(commentId, text, DateTimeOffset.UtcNow));
+        return await repo.GetUserComment(commentId) ?? throw NotFoundException.ForType<UserComment>(commentId);
+    }
+
+    public async Task<CommentThread> SetCommentThreadStatus(Guid threadId, ThreadStatus status)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        _ = await repo.GetCommentThread(threadId) ?? throw NotFoundException.ForType<CommentThread>(threadId);
+        await AddChange(new SetCommentThreadStatusChange(threadId, status, DateTimeOffset.UtcNow));
+        return await repo.GetCommentThread(threadId) ?? throw NotFoundException.ForType<CommentThread>(threadId);
+    }
+
+    public async Task DeleteUserComment(Guid commentId)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        var comment = await repo.GetUserComment(commentId) ?? throw NotFoundException.ForType<UserComment>(commentId);
+        AssertCurrentUserCanChangeComment(comment);
+        await AddChange(new DeleteChange<UserComment>(commentId));
+        await commentReadStatusService.RemoveUnreadComments([commentId]);
+    }
+
+    public async Task DeleteCommentThread(Guid threadId)
+    {
+        await using var repo = await repoFactory.CreateRepoAsync();
+        _ = await repo.GetCommentThread(threadId) ?? throw NotFoundException.ForType<CommentThread>(threadId);
+        await AddChange(new DeleteChange<CommentThread>(threadId));
+        await commentReadStatusService.MarkThreadRead(threadId);
+    }
+
+    public Task MarkCommentRead(Guid commentId)
+    {
+        return commentReadStatusService.MarkCommentRead(commentId);
+    }
+
+    public Task MarkCommentThreadRead(Guid threadId)
+    {
+        return commentReadStatusService.MarkThreadRead(threadId);
+    }
+
+    public Task MarkAllCommentsRead()
+    {
+        return commentReadStatusService.MarkAllRead();
+    }
+
+    private void StampCommentThreadAuthor(CommentThread thread, DateTimeOffset now)
+    {
+        if (thread.Id == Guid.Empty) thread.Id = Guid.NewGuid();
+        thread.AuthorId = RequireCommentUserId();
+        thread.AuthorName = ProjectData.LastUserName;
+        thread.CreatedAt = thread.CreatedAt == default ? now : thread.CreatedAt;
+        thread.UpdatedAt = thread.UpdatedAt == default ? thread.CreatedAt : thread.UpdatedAt;
+    }
+
+    private void StampCommentAuthor(UserComment comment, DateTimeOffset now)
+    {
+        if (comment.Id == Guid.Empty) comment.Id = Guid.NewGuid();
+        comment.AuthorId = RequireCommentUserId();
+        comment.AuthorName = ProjectData.LastUserName;
+        comment.CreatedAt = comment.CreatedAt == default ? now : comment.CreatedAt;
+        comment.UpdatedAt = comment.UpdatedAt == default ? comment.CreatedAt : comment.UpdatedAt;
+    }
+
+    private string RequireCommentUserId()
+    {
+        if (string.IsNullOrEmpty(ProjectData.LastUserId))
+            throw new ValidationException("Cannot create or modify comments without a known user identity.");
+        return ProjectData.LastUserId;
+    }
+
+    private void AssertCurrentUserCanChangeComment(UserComment comment)
+    {
+        if (comment.AuthorId == RequireCommentUserId()) return;
+        throw new UnauthorizedAccessException("Only the comment author can edit or delete this comment.");
+    }
+
     public void Dispose()
     {
     }
diff --git a/backend/FwLite/LcmCrdt/Data/LocalCommentReadStatusService.cs b/backend/FwLite/LcmCrdt/Data/LocalCommentReadStatusService.cs
new file mode 100644
index 0000000000..dd5a200b1b
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Data/LocalCommentReadStatusService.cs
@@ -0,0 +1,128 @@
+using LcmCrdt.Utils;
+using Microsoft.EntityFrameworkCore;
+
+namespace LcmCrdt.Data;
+
+public class LocalCommentReadStatusService(IDbContextFactory<LcmCrdtDbContext> dbContextFactory)
+{
+    public async Task<UserComment[]> GetUnreadComments(Guid? threadId = null)
+    {
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        var query = UnreadComments(dbContext);
+        if (threadId is not null)
+            query = query.Where(c => c.CommentThreadId == threadId);
+        return await query.ToArrayAsync();
+    }
+
+    public async Task<UserComment[]> GetUnreadCommentsForSubject(SubjectType subjectType, Guid subjectId)
+    {
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        var query =
+            from unreadComment in UnreadComments(dbContext)
+            join thread in dbContext.CommentThreads on unreadComment.CommentThreadId equals thread.Id
+            where thread.SubjectType == subjectType && thread.SubjectId == subjectId
+            select unreadComment;
+        return await query.ToArrayAsync();
+    }
+
+    public async Task<int> CountUnreadComments(Guid? threadId = null)
+    {
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        var query = UnreadComments(dbContext);
+        if (threadId is not null)
+            query = query.Where(c => c.CommentThreadId == threadId);
+        return await query.CountAsync();
+    }
+
+    public async Task MarkCommentRead(Guid commentId)
+    {
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        await dbContext.UnreadComments
+            .Where(c => c.CommentId == commentId)
+            .ExecuteDeleteAsync();
+    }
+
+    public async Task MarkThreadRead(Guid threadId)
+    {
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        await dbContext.UnreadComments
+            .Where(c => c.CommentThreadId == threadId)
+            .ExecuteDeleteAsync();
+    }
+
+    public async Task MarkAllRead()
+    {
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        await dbContext.UnreadComments.ExecuteDeleteAsync();
+    }
+
+    public async Task RemoveUnreadComments(IEnumerable<Guid> commentIds)
+    {
+        var ids = commentIds.Distinct().ToArray();
+        if (ids.Length == 0) return;
+
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        await dbContext.UnreadComments
+            .Where(c => ids.Contains(c.CommentId))
+            .ExecuteDeleteAsync();
+    }
+
+    public async Task MarkCommentsUnread(IEnumerable<(Guid CommentId, Guid CommentThreadId)> comments)
+    {
+        var commentsToMark = comments
+            .DistinctBy(c => c.CommentId)
+            .ToArray();
+        if (commentsToMark.Length == 0) return;
+
+        await using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        var commentIds = commentsToMark.Select(c => c.CommentId).ToArray();
+        var alreadyUnread = await dbContext.UnreadComments
+            .Where(c => commentIds.Contains(c.CommentId))
+            .Select(c => c.CommentId)
+            .ToArrayAsync();
+        var alreadyUnreadSet = alreadyUnread.ToHashSet();
+        var now = DateTimeOffset.UtcNow;
+        var toInsert = commentsToMark
+            .Where(comment => !alreadyUnreadSet.Contains(comment.CommentId))
+            .Select(comment => new UnreadComment
+            {
+                CommentId = comment.CommentId,
+                CommentThreadId = comment.CommentThreadId,
+                MarkedUnreadAt = now
+            })
+            .ToArray();
+        if (toInsert.Length == 0) return;
+
+        dbContext.UnreadComments.AddRange(toInsert);
+        try
+        {
+            await dbContext.SaveChangesAsync();
+        }
+        catch (DbUpdateException e) when (e.CausedByUniqueConstraintViolation())
+        {
+            // Concurrent callers can both pass the existence check; CommentId is the PK.
+            dbContext.ChangeTracker.Clear();
+            foreach (var unread in toInsert)
+            {
+                dbContext.UnreadComments.Add(unread);
+                try
+                {
+                    await dbContext.SaveChangesAsync();
+                }
+                catch (DbUpdateException ex) when (ex.CausedByUniqueConstraintViolation())
+                {
+                    dbContext.ChangeTracker.Clear();
+                }
+            }
+        }
+    }
+
+    private static IQueryable<UserComment> UnreadComments(LcmCrdtDbContext dbContext)
+    {
+        return
+            from unread in dbContext.UnreadComments
+            join comment in dbContext.UserComments on unread.CommentId equals comment.Id
+            orderby comment.CreatedAt, comment.Id
+            select comment;
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Data/MiniLcmRepository.cs b/backend/FwLite/LcmCrdt/Data/MiniLcmRepository.cs
index 4ed9fb5a2d..afbfe4aa2c 100644
--- a/backend/FwLite/LcmCrdt/Data/MiniLcmRepository.cs
+++ b/backend/FwLite/LcmCrdt/Data/MiniLcmRepository.cs
@@ -75,6 +75,8 @@ public void Dispose()
     public IQueryable<PartOfSpeech> PartsOfSpeech => dbContext.PartsOfSpeech;
     public IQueryable<Publication> Publications => dbContext.Publications;
     public IQueryable<CustomView> CustomViews => dbContext.CustomViews;
+    public IQueryable<CommentThread> CommentThreads => dbContext.CommentThreads;
+    public IQueryable<UserComment> UserComments => dbContext.UserComments;
 
 
     private WritingSystem? _defaultVernacularWs;
@@ -314,4 +316,14 @@ public async Task<int> GetEntryIndex(Guid entryId, string? query = null, IndexQu
             .AsQueryable(), cv => cv.Id == customViewId);
         return customView;
     }
+
+    public async Task<CommentThread?> GetCommentThread(Guid threadId)
+    {
+        return await AsyncExtensions.SingleOrDefaultAsync(CommentThreads.AsQueryable(), t => t.Id == threadId);
+    }
+
+    public async Task<UserComment?> GetUserComment(Guid commentId)
+    {
+        return await AsyncExtensions.SingleOrDefaultAsync(UserComments.AsQueryable(), c => c.Id == commentId);
+    }
 }
diff --git a/backend/FwLite/LcmCrdt/Data/UnreadComment.cs b/backend/FwLite/LcmCrdt/Data/UnreadComment.cs
new file mode 100644
index 0000000000..0618736a6a
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Data/UnreadComment.cs
@@ -0,0 +1,8 @@
+namespace LcmCrdt.Data;
+
+public class UnreadComment
+{
+    public Guid CommentId { get; set; }
+    public Guid CommentThreadId { get; set; }
+    public DateTimeOffset MarkedUnreadAt { get; set; }
+}
diff --git a/backend/FwLite/LcmCrdt/LcmCrdtDbContext.cs b/backend/FwLite/LcmCrdt/LcmCrdtDbContext.cs
index af8cd93174..e1fcf6eac3 100644
--- a/backend/FwLite/LcmCrdt/LcmCrdtDbContext.cs
+++ b/backend/FwLite/LcmCrdt/LcmCrdtDbContext.cs
@@ -1,4 +1,6 @@
+using System.ComponentModel;
 using System.Text.Json;
+using LcmCrdt.Data;
 using LcmCrdt.FullTextSearch;
 using SIL.Harmony;
 using SIL.Harmony.Db;
@@ -28,6 +30,9 @@ IOptions<CrdtConfig> options
     public IQueryable<PartOfSpeech> PartsOfSpeech => Set<PartOfSpeech>().AsNoTracking();
     public IQueryable<Publication> Publications => Set<Publication>().AsNoTracking();
     public IQueryable<CustomView> CustomViews => Set<CustomView>().AsNoTracking();
+    public IQueryable<CommentThread> CommentThreads => Set<CommentThread>().AsNoTracking();
+    public IQueryable<UserComment> UserComments => Set<UserComment>().AsNoTracking();
+    public DbSet<UnreadComment> UnreadComments => Set<UnreadComment>();
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
@@ -45,6 +50,10 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
         var morphTypeModel = modelBuilder.Entity<MorphType>();
         morphTypeModel.HasIndex(m => m.Kind).IsUnique();
 
+        var unreadCommentModel = modelBuilder.Entity<UnreadComment>();
+        unreadCommentModel.HasKey(c => c.CommentId);
+        unreadCommentModel.HasIndex(c => c.CommentThreadId);
+
         var senseModel = modelBuilder.Entity<Sense>();
         senseModel.Property(s => s.Pictures).HasColumnType("jsonb").HasDefaultValueSql("'[]'");
     }
@@ -62,6 +71,8 @@ protected override void ConfigureConventions(ModelConfigurationBuilder builder)
             .HaveConversion<RichMultiStringDbConverter>();
         builder.Properties<WritingSystemId>()
             .HaveConversion<WritingSystemIdConverter>();
+        builder.Properties<DateTimeOffset>()
+            .HaveConversion<DateTimeOffsetDbConverter>();
         builder.Properties<List<Picture>>()
             .HaveConversion<PictureListDbConverter>();
     }
@@ -97,6 +108,11 @@ private class WritingSystemIdConverter() : ValueConverter<WritingSystemId, strin
         id => id.Code,
         code => new WritingSystemId(code));
 
+    private class DateTimeOffsetDbConverter() : ValueConverter<DateTimeOffset, DateTime>(
+        d => d.UtcDateTime,
+        //need to use ticks here because the DateTime is stored as UTC, but the db records it as unspecified
+        d => new DateTimeOffset(d.Ticks, TimeSpan.Zero));
+
     private class PictureListDbConverter() : ValueConverter<List<Picture>, string>(
         pic => JsonSerializer.Serialize(pic, (JsonSerializerOptions?)null),
         json => JsonSerializer.Deserialize<List<Picture>>(json, (JsonSerializerOptions?)null) ?? new());
diff --git a/backend/FwLite/LcmCrdt/LcmCrdtKernel.cs b/backend/FwLite/LcmCrdt/LcmCrdtKernel.cs
index d6282371ed..970116a127 100644
--- a/backend/FwLite/LcmCrdt/LcmCrdtKernel.cs
+++ b/backend/FwLite/LcmCrdt/LcmCrdtKernel.cs
@@ -6,6 +6,7 @@
 using SIL.Harmony.Changes;
 using LcmCrdt.Changes;
 using LcmCrdt.Changes.CustomJsonPatches;
+using LcmCrdt.Changes.Comments;
 using LcmCrdt.Changes.Entries;
 using LcmCrdt.Changes.ExampleSentences;
 using LcmCrdt.Data;
@@ -75,6 +76,7 @@ public static IServiceCollection AddLcmCrdtClientCore(this IServiceCollection se
         services.AddSingleton<ProjectDataCache>();
         services.AddScoped<CurrentProjectService>();
         services.AddScoped<HistoryService>();
+        services.AddScoped<LocalCommentReadStatusService>();
         services.AddScoped<LcmMediaService>();
         services.AddScoped<SyncRepository>();
         services.AddSingleton<CrdtProjectsService>();
@@ -287,6 +289,20 @@ public static void ConfigureCrdt(CrdtConfig config)
                     .HasColumnType("jsonb")
                     .HasConversion(writingSystemArrayConverter);
             })
+            .Add<CommentThread>(builder =>
+            {
+                builder.HasIndex(t => new { t.SubjectType, t.SubjectId });
+                builder.HasIndex(t => t.CreatedAt);
+                builder.HasMany(t => t.Comments)
+                    .WithOne()
+                    .HasForeignKey(c => c.CommentThreadId)
+                    .OnDelete(DeleteBehavior.Cascade);
+            })
+            .Add<UserComment>(builder =>
+            {
+                builder.HasIndex(c => c.CommentThreadId);
+                builder.HasIndex(c => c.CreatedAt);
+            })
             .Add<MorphType>()
             .Add<ComplexFormComponent>(builder =>
             {
@@ -364,6 +380,12 @@ public static void ConfigureCrdt(CrdtConfig config)
             .Add<CreateCustomViewChange>()
             .Add<EditCustomViewChange>()
             .Add<DeleteChange<CustomView>>()
+            .Add<CreateCommentThreadChange>()
+            .Add<CreateUserCommentChange>()
+            .Add<EditUserCommentChange>()
+            .Add<SetCommentThreadStatusChange>()
+            .Add<DeleteChange<CommentThread>>()
+            .Add<DeleteChange<UserComment>>()
             .Add<CreateMorphTypeChange>()
             .Add<Changes.SetOrderChange<Sense>>()
             .Add<Changes.SetOrderChange<ComplexFormComponent>>()
diff --git a/backend/FwLite/LcmCrdt/Migrations/20260629042525_AddComments.Designer.cs b/backend/FwLite/LcmCrdt/Migrations/20260629042525_AddComments.Designer.cs
new file mode 100644
index 0000000000..7ab223c8e2
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Migrations/20260629042525_AddComments.Designer.cs
@@ -0,0 +1,969 @@
+// <auto-generated />
+using System;
+using System.Collections.Generic;
+using LcmCrdt;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace LcmCrdt.Migrations
+{
+    [DbContext(typeof(LcmCrdtDbContext))]
+    [Migration("20260629042525_AddComments")]
+    partial class AddComments
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
+
+            modelBuilder.Entity("LcmCrdt.Data.UnreadComment", b =>
+                {
+                    b.Property<Guid>("CommentId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommentThreadId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("MarkedUnreadAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("CommentId");
+
+                    b.HasIndex("CommentThreadId");
+
+                    b.ToTable("UnreadComments");
+                });
+
+            modelBuilder.Entity("LcmCrdt.FullTextSearch.EntrySearchRecord", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("CitationForm")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Definition")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Gloss")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Headword")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LexemeForm")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("EntrySearchRecord", null, t =>
+                        {
+                            t.ExcludeFromMigrations();
+                        });
+                });
+
+            modelBuilder.Entity("LcmCrdt.ProjectData", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ClientId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Code")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("FwProjectId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LastUserId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LastUserName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("OriginDomain")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasDefaultValue("Editor");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("ProjectData");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid>("SubjectId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("SubjectType")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("SubjectType", "SubjectId");
+
+                    b.ToTable("CommentThread");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormComponent", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ComplexFormEntryId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("ComplexFormHeadword")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ComponentEntryId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("ComponentHeadword")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("ComponentSenseId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("ComponentSenseId");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ComponentEntryId");
+
+                    b.HasIndex("ComponentSenseId");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("ComplexFormEntryId", "ComponentEntryId")
+                        .IsUnique()
+                        .HasFilter("ComponentSenseId IS NULL");
+
+                    b.HasIndex("ComplexFormEntryId", "ComponentEntryId", "ComponentSenseId")
+                        .IsUnique()
+                        .HasFilter("ComponentSenseId IS NOT NULL");
+
+                    b.ToTable("ComplexFormComponents", (string)null);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormType", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("ComplexFormType");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CustomView", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Analysis")
+                        .HasColumnType("jsonb");
+
+                    b.Property<int>("Base")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("EntryFields")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("ExampleFields")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("SenseFields")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Vernacular")
+                        .HasColumnType("jsonb");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("CustomView");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Entry", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("CitationForm")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("ComplexFormTypes")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("HomographNumber")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("LexemeForm")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("LiteralMeaning")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<int>("MorphType")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Note")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("PublishIn")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("Entry");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ExampleSentence", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<string>("Reference")
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid>("SenseId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Sentence")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Translations")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SenseId");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("ExampleSentence");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.MorphType", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Abbreviation")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<int>("Kind")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("Postfix")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Prefix")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("SecondaryOrder")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Kind")
+                        .IsUnique();
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("MorphType");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.PartOfSpeech", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<bool>("Predefined")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("PartOfSpeech");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Publication", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("Publication");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.SemanticDomain", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Code")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<bool>("Predefined")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("SemanticDomain");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Sense", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Definition")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("EntryId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Gloss")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<Guid?>("PartOfSpeechId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("SemanticDomains")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EntryId");
+
+                    b.HasIndex("PartOfSpeechId");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("Sense");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.UserComment", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommentThreadId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("PreviousCommentId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Text")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CommentThreadId");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("UserComment");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.WritingSystem", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Abbreviation")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Exemplars")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("Font")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("WsId")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("WsId", "Type")
+                        .IsUnique();
+
+                    b.ToTable("WritingSystem");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Commit", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ClientId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Hash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Metadata")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("ParentHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.ComplexProperty(typeof(Dictionary<string, object>), "HybridDateTime", "SIL.Harmony.Commit.HybridDateTime#HybridDateTime", b1 =>
+                        {
+                            b1.IsRequired();
+
+                            b1.Property<long>("Counter")
+                                .HasColumnType("INTEGER")
+                                .HasColumnName("Counter");
+
+                            b1.Property<DateTime>("DateTime")
+                                .HasColumnType("TEXT")
+                                .HasColumnName("DateTime");
+                        });
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Commits", (string)null);
+
+                    b.HasAnnotation("CustomIndex:CompositeIndexes", "[{\"paths\":[\"HybridDateTime.DateTime\",\"HybridDateTime.Counter\",\"Id\"],\"unique\":false,\"name\":\"IX_Commits_DateTime_Counter_Id\"}]");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Core.ChangeEntity<SIL.Harmony.Changes.IChange>", b =>
+                {
+                    b.Property<Guid>("CommitId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Index")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Change")
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid>("EntityId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("CommitId", "Index");
+
+                    b.ToTable("ChangeEntities", (string)null);
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Db.ObjectSnapshot", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommitId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Entity")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid>("EntityId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("EntityIsDeleted")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("IsRoot")
+                        .HasColumnType("INTEGER");
+
+                    b.PrimitiveCollection<string>("References")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("TypeName")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EntityId");
+
+                    b.HasIndex("CommitId", "EntityId")
+                        .IsUnique();
+
+                    b.ToTable("Snapshots", (string)null);
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Resource.LocalResource", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LocalPath")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("LocalResource");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Resource.RemoteResource", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("RemoteId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("RemoteResource");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.CommentThread", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormComponent", b =>
+                {
+                    b.HasOne("MiniLcm.Models.Entry", null)
+                        .WithMany("Components")
+                        .HasForeignKey("ComplexFormEntryId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MiniLcm.Models.Entry", null)
+                        .WithMany("ComplexForms")
+                        .HasForeignKey("ComponentEntryId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MiniLcm.Models.Sense", null)
+                        .WithMany()
+                        .HasForeignKey("ComponentSenseId")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.ComplexFormComponent", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormType", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.ComplexFormType", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CustomView", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.CustomView", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Entry", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.Entry", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ExampleSentence", b =>
+                {
+                    b.HasOne("MiniLcm.Models.Sense", null)
+                        .WithMany("ExampleSentences")
+                        .HasForeignKey("SenseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.ExampleSentence", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.MorphType", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.MorphType", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.PartOfSpeech", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.PartOfSpeech", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Publication", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.Publication", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.SemanticDomain", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.SemanticDomain", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Sense", b =>
+                {
+                    b.HasOne("MiniLcm.Models.Entry", null)
+                        .WithMany("Senses")
+                        .HasForeignKey("EntryId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MiniLcm.Models.PartOfSpeech", "PartOfSpeech")
+                        .WithMany()
+                        .HasForeignKey("PartOfSpeechId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.Sense", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("PartOfSpeech");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.UserComment", b =>
+                {
+                    b.HasOne("MiniLcm.Models.CommentThread", null)
+                        .WithMany()
+                        .HasForeignKey("CommentThreadId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.UserComment", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.WritingSystem", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.WritingSystem", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Core.ChangeEntity<SIL.Harmony.Changes.IChange>", b =>
+                {
+                    b.HasOne("SIL.Harmony.Commit", null)
+                        .WithMany("ChangeEntities")
+                        .HasForeignKey("CommitId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Db.ObjectSnapshot", b =>
+                {
+                    b.HasOne("SIL.Harmony.Commit", "Commit")
+                        .WithMany("Snapshots")
+                        .HasForeignKey("CommitId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Commit");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Resource.RemoteResource", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("SIL.Harmony.Resource.RemoteResource", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Entry", b =>
+                {
+                    b.Navigation("ComplexForms");
+
+                    b.Navigation("Components");
+
+                    b.Navigation("Senses");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Sense", b =>
+                {
+                    b.Navigation("ExampleSentences");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Commit", b =>
+                {
+                    b.Navigation("ChangeEntities");
+
+                    b.Navigation("Snapshots");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Migrations/20260629042525_AddComments.cs b/backend/FwLite/LcmCrdt/Migrations/20260629042525_AddComments.cs
new file mode 100644
index 0000000000..69e0d2266f
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Migrations/20260629042525_AddComments.cs
@@ -0,0 +1,134 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace LcmCrdt.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddComments : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "CommentThread",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "TEXT", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "TEXT", nullable: true),
+                    SubjectId = table.Column<Guid>(type: "TEXT", nullable: false),
+                    SubjectType = table.Column<int>(type: "INTEGER", nullable: false),
+                    Status = table.Column<int>(type: "INTEGER", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "TEXT", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "TEXT", nullable: false),
+                    SnapshotId = table.Column<Guid>(type: "TEXT", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_CommentThread", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_CommentThread_Snapshots_SnapshotId",
+                        column: x => x.SnapshotId,
+                        principalTable: "Snapshots",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.SetNull);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "UnreadComments",
+                columns: table => new
+                {
+                    CommentId = table.Column<Guid>(type: "TEXT", nullable: false),
+                    CommentThreadId = table.Column<Guid>(type: "TEXT", nullable: false),
+                    MarkedUnreadAt = table.Column<DateTime>(type: "TEXT", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_UnreadComments", x => x.CommentId);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "UserComment",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "TEXT", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "TEXT", nullable: true),
+                    CommentThreadId = table.Column<Guid>(type: "TEXT", nullable: false),
+                    PreviousCommentId = table.Column<Guid>(type: "TEXT", nullable: true),
+                    Text = table.Column<string>(type: "TEXT", nullable: false),
+                    AuthorId = table.Column<string>(type: "TEXT", nullable: true),
+                    AuthorName = table.Column<string>(type: "TEXT", nullable: true),
+                    CreatedAt = table.Column<DateTime>(type: "TEXT", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "TEXT", nullable: false),
+                    SnapshotId = table.Column<Guid>(type: "TEXT", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_UserComment", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_UserComment_CommentThread_CommentThreadId",
+                        column: x => x.CommentThreadId,
+                        principalTable: "CommentThread",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                    table.ForeignKey(
+                        name: "FK_UserComment_Snapshots_SnapshotId",
+                        column: x => x.SnapshotId,
+                        principalTable: "Snapshots",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.SetNull);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_CommentThread_CreatedAt",
+                table: "CommentThread",
+                column: "CreatedAt");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_CommentThread_SnapshotId",
+                table: "CommentThread",
+                column: "SnapshotId",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_CommentThread_SubjectType_SubjectId",
+                table: "CommentThread",
+                columns: new[] { "SubjectType", "SubjectId" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_UnreadComments_CommentThreadId",
+                table: "UnreadComments",
+                column: "CommentThreadId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_UserComment_CommentThreadId",
+                table: "UserComment",
+                column: "CommentThreadId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_UserComment_CreatedAt",
+                table: "UserComment",
+                column: "CreatedAt");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_UserComment_SnapshotId",
+                table: "UserComment",
+                column: "SnapshotId",
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "UnreadComments");
+
+            migrationBuilder.DropTable(
+                name: "UserComment");
+
+            migrationBuilder.DropTable(
+                name: "CommentThread");
+        }
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Migrations/20260706032956_AddCommentThreadAuthor.Designer.cs b/backend/FwLite/LcmCrdt/Migrations/20260706032956_AddCommentThreadAuthor.Designer.cs
new file mode 100644
index 0000000000..afb0da4f44
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Migrations/20260706032956_AddCommentThreadAuthor.Designer.cs
@@ -0,0 +1,989 @@
+// <auto-generated />
+using System;
+using System.Collections.Generic;
+using LcmCrdt;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace LcmCrdt.Migrations
+{
+    [DbContext(typeof(LcmCrdtDbContext))]
+    [Migration("20260706032956_AddCommentThreadAuthor")]
+    partial class AddCommentThreadAuthor
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
+
+            modelBuilder.Entity("LcmCrdt.Data.UnreadComment", b =>
+                {
+                    b.Property<Guid>("CommentId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommentThreadId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("MarkedUnreadAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("CommentId");
+
+                    b.HasIndex("CommentThreadId");
+
+                    b.ToTable("UnreadComments");
+                });
+
+            modelBuilder.Entity("LcmCrdt.FullTextSearch.EntrySearchRecord", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("CitationForm")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Definition")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Gloss")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Headword")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LexemeForm")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("EntrySearchRecord", null, t =>
+                        {
+                            t.ExcludeFromMigrations();
+                        });
+                });
+
+            modelBuilder.Entity("LcmCrdt.ProjectData", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ClientId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Code")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("FwProjectId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LastUserId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LastUserName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("OriginDomain")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasDefaultValue("Editor");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("ProjectData");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid>("SubjectId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("SubjectType")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("SubjectType", "SubjectId");
+
+                    b.ToTable("CommentThread");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormComponent", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ComplexFormEntryId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("ComplexFormHeadword")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ComponentEntryId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("ComponentHeadword")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("ComponentSenseId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("ComponentSenseId");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ComponentEntryId");
+
+                    b.HasIndex("ComponentSenseId");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("ComplexFormEntryId", "ComponentEntryId")
+                        .IsUnique()
+                        .HasFilter("ComponentSenseId IS NULL");
+
+                    b.HasIndex("ComplexFormEntryId", "ComponentEntryId", "ComponentSenseId")
+                        .IsUnique()
+                        .HasFilter("ComponentSenseId IS NOT NULL");
+
+                    b.ToTable("ComplexFormComponents", (string)null);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormType", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("ComplexFormType");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CustomView", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Analysis")
+                        .HasColumnType("jsonb");
+
+                    b.Property<int>("Base")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("EntryFields")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("ExampleFields")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("SenseFields")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Vernacular")
+                        .HasColumnType("jsonb");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("CustomView");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Entry", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("CitationForm")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("ComplexFormTypes")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("HomographNumber")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("LexemeForm")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("LiteralMeaning")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<int>("MorphType")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Note")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("PublishIn")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("Entry");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ExampleSentence", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<string>("Reference")
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid>("SenseId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Sentence")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Translations")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SenseId");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("ExampleSentence");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.MorphType", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Abbreviation")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<int>("Kind")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("Postfix")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Prefix")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("SecondaryOrder")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Kind")
+                        .IsUnique();
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("MorphType");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.PartOfSpeech", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<bool>("Predefined")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("PartOfSpeech");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Publication", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("IsMain")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("Publication");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.SemanticDomain", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Code")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<bool>("Predefined")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("SemanticDomain");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Sense", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Definition")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("EntryId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Gloss")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<Guid?>("PartOfSpeechId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Pictures")
+                        .IsRequired()
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("jsonb")
+                        .HasDefaultValueSql("'[]'");
+
+                    b.Property<string>("SemanticDomains")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EntryId");
+
+                    b.HasIndex("PartOfSpeechId");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("Sense");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.UserComment", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommentThreadId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("PreviousCommentId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Text")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CommentThreadId");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("UserComment");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.WritingSystem", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Abbreviation")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Exemplars")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("Font")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("Order")
+                        .HasColumnType("REAL");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("WsId")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("WsId", "Type")
+                        .IsUnique();
+
+                    b.ToTable("WritingSystem");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Commit", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ClientId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Hash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Metadata")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<string>("ParentHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.ComplexProperty(typeof(Dictionary<string, object>), "HybridDateTime", "SIL.Harmony.Commit.HybridDateTime#HybridDateTime", b1 =>
+                        {
+                            b1.IsRequired();
+
+                            b1.Property<long>("Counter")
+                                .HasColumnType("INTEGER")
+                                .HasColumnName("Counter");
+
+                            b1.Property<DateTime>("DateTime")
+                                .HasColumnType("TEXT")
+                                .HasColumnName("DateTime");
+                        });
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Commits", (string)null);
+
+                    b.HasAnnotation("CustomIndex:CompositeIndexes", "[{\"paths\":[\"HybridDateTime.DateTime\",\"HybridDateTime.Counter\",\"Id\"],\"unique\":false,\"name\":\"IX_Commits_DateTime_Counter_Id\"}]");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Core.ChangeEntity<SIL.Harmony.Changes.IChange>", b =>
+                {
+                    b.Property<Guid>("CommitId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Index")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Change")
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid>("EntityId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("CommitId", "Index");
+
+                    b.ToTable("ChangeEntities", (string)null);
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Db.ObjectSnapshot", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommitId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Entity")
+                        .IsRequired()
+                        .HasColumnType("jsonb");
+
+                    b.Property<Guid>("EntityId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("EntityIsDeleted")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("IsRoot")
+                        .HasColumnType("INTEGER");
+
+                    b.PrimitiveCollection<string>("References")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("TypeName")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EntityId");
+
+                    b.HasIndex("CommitId", "EntityId")
+                        .IsUnique();
+
+                    b.ToTable("Snapshots", (string)null);
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Resource.LocalResource", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("LocalPath")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("LocalResource");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Resource.RemoteResource", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("RemoteId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("RemoteResource");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.CommentThread", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormComponent", b =>
+                {
+                    b.HasOne("MiniLcm.Models.Entry", null)
+                        .WithMany("Components")
+                        .HasForeignKey("ComplexFormEntryId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MiniLcm.Models.Entry", null)
+                        .WithMany("ComplexForms")
+                        .HasForeignKey("ComponentEntryId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MiniLcm.Models.Sense", null)
+                        .WithMany()
+                        .HasForeignKey("ComponentSenseId")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.ComplexFormComponent", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ComplexFormType", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.ComplexFormType", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CustomView", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.CustomView", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Entry", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.Entry", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.ExampleSentence", b =>
+                {
+                    b.HasOne("MiniLcm.Models.Sense", null)
+                        .WithMany("ExampleSentences")
+                        .HasForeignKey("SenseId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.ExampleSentence", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.MorphType", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.MorphType", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.PartOfSpeech", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.PartOfSpeech", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Publication", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.Publication", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.SemanticDomain", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.SemanticDomain", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Sense", b =>
+                {
+                    b.HasOne("MiniLcm.Models.Entry", null)
+                        .WithMany("Senses")
+                        .HasForeignKey("EntryId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("MiniLcm.Models.PartOfSpeech", "PartOfSpeech")
+                        .WithMany()
+                        .HasForeignKey("PartOfSpeechId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.Sense", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("PartOfSpeech");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.UserComment", b =>
+                {
+                    b.HasOne("MiniLcm.Models.CommentThread", null)
+                        .WithMany("Comments")
+                        .HasForeignKey("CommentThreadId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.UserComment", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.WritingSystem", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.WritingSystem", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Core.ChangeEntity<SIL.Harmony.Changes.IChange>", b =>
+                {
+                    b.HasOne("SIL.Harmony.Commit", null)
+                        .WithMany("ChangeEntities")
+                        .HasForeignKey("CommitId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Db.ObjectSnapshot", b =>
+                {
+                    b.HasOne("SIL.Harmony.Commit", "Commit")
+                        .WithMany("Snapshots")
+                        .HasForeignKey("CommitId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Commit");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Resource.RemoteResource", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("SIL.Harmony.Resource.RemoteResource", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.Navigation("Comments");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Entry", b =>
+                {
+                    b.Navigation("ComplexForms");
+
+                    b.Navigation("Components");
+
+                    b.Navigation("Senses");
+                });
+
+            modelBuilder.Entity("MiniLcm.Models.Sense", b =>
+                {
+                    b.Navigation("ExampleSentences");
+                });
+
+            modelBuilder.Entity("SIL.Harmony.Commit", b =>
+                {
+                    b.Navigation("ChangeEntities");
+
+                    b.Navigation("Snapshots");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Migrations/20260706032956_AddCommentThreadAuthor.cs b/backend/FwLite/LcmCrdt/Migrations/20260706032956_AddCommentThreadAuthor.cs
new file mode 100644
index 0000000000..2e4a062d73
--- /dev/null
+++ b/backend/FwLite/LcmCrdt/Migrations/20260706032956_AddCommentThreadAuthor.cs
@@ -0,0 +1,38 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace LcmCrdt.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddCommentThreadAuthor : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "AuthorId",
+                table: "CommentThread",
+                type: "TEXT",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "AuthorName",
+                table: "CommentThread",
+                type: "TEXT",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "AuthorId",
+                table: "CommentThread");
+
+            migrationBuilder.DropColumn(
+                name: "AuthorName",
+                table: "CommentThread");
+        }
+    }
+}
diff --git a/backend/FwLite/LcmCrdt/Migrations/LcmCrdtDbContextModelSnapshot.cs b/backend/FwLite/LcmCrdt/Migrations/LcmCrdtDbContextModelSnapshot.cs
index 650a5b9420..ae72a45791 100644
--- a/backend/FwLite/LcmCrdt/Migrations/LcmCrdtDbContextModelSnapshot.cs
+++ b/backend/FwLite/LcmCrdt/Migrations/LcmCrdtDbContextModelSnapshot.cs
@@ -18,6 +18,25 @@ protected override void BuildModel(ModelBuilder modelBuilder)
 #pragma warning disable 612, 618
             modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
 
+            modelBuilder.Entity("LcmCrdt.Data.UnreadComment", b =>
+                {
+                    b.Property<Guid>("CommentId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommentThreadId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("MarkedUnreadAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("CommentId");
+
+                    b.HasIndex("CommentThreadId");
+
+                    b.ToTable("UnreadComments");
+                });
+
             modelBuilder.Entity("LcmCrdt.FullTextSearch.EntrySearchRecord", b =>
                 {
                     b.Property<Guid>("Id")
@@ -92,6 +111,51 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("ProjectData");
                 });
 
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid>("SubjectId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("SubjectType")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.HasIndex("SubjectType", "SubjectId");
+
+                    b.ToTable("CommentThread");
+                });
+
             modelBuilder.Entity("MiniLcm.Models.ComplexFormComponent", b =>
                 {
                     b.Property<Guid>("Id")
@@ -114,7 +178,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .HasColumnType("TEXT")
                         .HasColumnName("ComponentSenseId");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<double>("Order")
@@ -149,7 +213,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .ValueGeneratedOnAdd()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("Name")
@@ -179,7 +243,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.Property<int>("Base")
                         .HasColumnType("INTEGER");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("EntryFields")
@@ -226,7 +290,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .IsRequired()
                         .HasColumnType("jsonb");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<int>("HomographNumber")
@@ -268,7 +332,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .ValueGeneratedOnAdd()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<double>("Order")
@@ -311,7 +375,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .IsRequired()
                         .HasColumnType("jsonb");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("Description")
@@ -354,7 +418,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .ValueGeneratedOnAdd()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("Name")
@@ -381,7 +445,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .ValueGeneratedOnAdd()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<bool>("IsMain")
@@ -412,7 +476,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .IsRequired()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("Name")
@@ -443,7 +507,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .IsRequired()
                         .HasColumnType("jsonb");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<Guid>("EntryId")
@@ -484,6 +548,52 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("Sense");
                 });
 
+            modelBuilder.Entity("MiniLcm.Models.UserComment", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AuthorName")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("CommentThreadId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("PreviousCommentId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid?>("SnapshotId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Text")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CommentThreadId");
+
+                    b.HasIndex("CreatedAt");
+
+                    b.HasIndex("SnapshotId")
+                        .IsUnique();
+
+                    b.ToTable("UserComment");
+                });
+
             modelBuilder.Entity("MiniLcm.Models.WritingSystem", b =>
                 {
                     b.Property<Guid>("Id")
@@ -494,7 +604,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .IsRequired()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("Exemplars")
@@ -654,7 +764,7 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .ValueGeneratedOnAdd()
                         .HasColumnType("TEXT");
 
-                    b.Property<DateTimeOffset?>("DeletedAt")
+                    b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("TEXT");
 
                     b.Property<string>("RemoteId")
@@ -671,6 +781,14 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.ToTable("RemoteResource");
                 });
 
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.CommentThread", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
             modelBuilder.Entity("MiniLcm.Models.ComplexFormComponent", b =>
                 {
                     b.HasOne("MiniLcm.Models.Entry", null)
@@ -787,6 +905,20 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                     b.Navigation("PartOfSpeech");
                 });
 
+            modelBuilder.Entity("MiniLcm.Models.UserComment", b =>
+                {
+                    b.HasOne("MiniLcm.Models.CommentThread", null)
+                        .WithMany("Comments")
+                        .HasForeignKey("CommentThreadId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
+                        .WithOne()
+                        .HasForeignKey("MiniLcm.Models.UserComment", "SnapshotId")
+                        .OnDelete(DeleteBehavior.SetNull);
+                });
+
             modelBuilder.Entity("MiniLcm.Models.WritingSystem", b =>
                 {
                     b.HasOne("SIL.Harmony.Db.ObjectSnapshot", null)
@@ -823,6 +955,11 @@ protected override void BuildModel(ModelBuilder modelBuilder)
                         .OnDelete(DeleteBehavior.SetNull);
                 });
 
+            modelBuilder.Entity("MiniLcm.Models.CommentThread", b =>
+                {
+                    b.Navigation("Comments");
+                });
+
             modelBuilder.Entity("MiniLcm.Models.Entry", b =>
                 {
                     b.Navigation("ComplexForms");
diff --git a/backend/FwLite/MiniLcm/IMiniLcmReadApi.cs b/backend/FwLite/MiniLcm/IMiniLcmReadApi.cs
index 36523faf83..827482aa83 100644
--- a/backend/FwLite/MiniLcm/IMiniLcmReadApi.cs
+++ b/backend/FwLite/MiniLcm/IMiniLcmReadApi.cs
@@ -49,6 +49,34 @@ IAsyncEnumerable<CustomView> GetCustomViews()
     {
         throw new NotSupportedException("Custom views are only supported by CRDT projects");
     }
+    IAsyncEnumerable<CommentThread> GetCommentThreads(SubjectType subjectType, Guid subjectId, bool includeComments = false)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task<CommentThread?> GetCommentThread(Guid id)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    IAsyncEnumerable<UserComment> GetUserComments(Guid threadId)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task<UserComment?> GetUserComment(Guid id)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    IAsyncEnumerable<UserComment> GetUnreadComments(Guid? threadId = null)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    IAsyncEnumerable<UserComment> GetUnreadCommentsForSubject(SubjectType subjectType, Guid subjectId)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task<int> CountUnreadComments(Guid? threadId = null)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
 }
 
 public record IndexQueryOptions(
diff --git a/backend/FwLite/MiniLcm/IMiniLcmWriteApi.cs b/backend/FwLite/MiniLcm/IMiniLcmWriteApi.cs
index 310095dd30..a09f955573 100644
--- a/backend/FwLite/MiniLcm/IMiniLcmWriteApi.cs
+++ b/backend/FwLite/MiniLcm/IMiniLcmWriteApi.cs
@@ -174,6 +174,45 @@ Task DeleteCustomView(Guid id)
     }
     #endregion
 
+    #region Comments
+    Task<CommentThread> CreateCommentThread(CommentThread thread, UserComment firstComment)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task<UserComment> AddUserComment(Guid threadId, UserComment comment)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task<UserComment> EditUserComment(Guid commentId, string text)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task<CommentThread> SetCommentThreadStatus(Guid threadId, ThreadStatus status)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task DeleteUserComment(Guid commentId)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task DeleteCommentThread(Guid threadId)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task MarkCommentRead(Guid commentId)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task MarkCommentThreadRead(Guid threadId)
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    Task MarkAllCommentsRead()
+    {
+        throw new NotSupportedException("Comments are only supported by CRDT projects");
+    }
+    #endregion
+
 
     /// <summary>
     /// Imports the provided semantic domains in bulk.
diff --git a/backend/FwLite/MiniLcm/Models/Comments.cs b/backend/FwLite/MiniLcm/Models/Comments.cs
new file mode 100644
index 0000000000..3f1c9c3508
--- /dev/null
+++ b/backend/FwLite/MiniLcm/Models/Comments.cs
@@ -0,0 +1,79 @@
+using System.Text.Json.Serialization;
+
+namespace MiniLcm.Models;
+
+[JsonConverter(typeof(JsonStringEnumConverter))]
+public enum ThreadStatus
+{
+    Open,
+    Closed
+}
+
+[JsonConverter(typeof(JsonStringEnumConverter))]
+public enum SubjectType
+{
+    Unknown = 0,
+    Entry,
+    Sense,
+    ExampleSentence
+}
+
+public record CommentThread : IObjectWithId<CommentThread>
+{
+    public Guid Id { get; set; }
+    public DateTimeOffset? DeletedAt { get; set; }
+    public Guid SubjectId { get; set; }
+    public SubjectType SubjectType { get; set; }
+    public ThreadStatus Status { get; set; } = ThreadStatus.Open;
+    public string? AuthorId { get; set; }
+    public string? AuthorName { get; set; }
+    public DateTimeOffset CreatedAt { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+    public List<UserComment>? Comments { get; set; }
+
+    public Guid[] GetReferences()
+    {
+        return [];
+    }
+
+    public void RemoveReference(Guid id, DateTimeOffset time)
+    {
+    }
+
+    public CommentThread Copy()
+    {
+        return this with
+        {
+            Comments = Comments?.Select(comment => comment.Copy()).ToList()
+        };
+    }
+}
+
+public record UserComment : IObjectWithId<UserComment>
+{
+    public Guid Id { get; set; }
+    public DateTimeOffset? DeletedAt { get; set; }
+    public Guid CommentThreadId { get; set; }
+    public Guid? PreviousCommentId { get; set; }
+    public required string Text { get; set; }
+    public string? AuthorId { get; set; }
+    public string? AuthorName { get; set; }
+    public DateTimeOffset CreatedAt { get; set; }
+    public DateTimeOffset UpdatedAt { get; set; }
+
+    public Guid[] GetReferences()
+    {
+        return [CommentThreadId];
+    }
+
+    public void RemoveReference(Guid id, DateTimeOffset time)
+    {
+        if (id == CommentThreadId)
+            DeletedAt = time;
+    }
+
+    public UserComment Copy()
+    {
+        return this with { };
+    }
+}
diff --git a/backend/FwLite/MiniLcm/Models/IObjectWithId.cs b/backend/FwLite/MiniLcm/Models/IObjectWithId.cs
index 606dca4192..4fd7db364a 100644
--- a/backend/FwLite/MiniLcm/Models/IObjectWithId.cs
+++ b/backend/FwLite/MiniLcm/Models/IObjectWithId.cs
@@ -13,6 +13,8 @@ namespace MiniLcm.Models;
 [JsonDerivedType(typeof(ComplexFormType), nameof(ComplexFormType))]
 [JsonDerivedType(typeof(ComplexFormComponent), nameof(ComplexFormComponent))]
 [JsonDerivedType(typeof(CustomView), nameof(CustomView))]
+[JsonDerivedType(typeof(CommentThread), nameof(CommentThread))]
+[JsonDerivedType(typeof(UserComment), nameof(UserComment))]
 [JsonDerivedType(typeof(MorphType), nameof(MorphType))]
 public interface IObjectWithId
 {
diff --git a/backend/FwLite/MiniLcm/Normalization/MiniLcmApiWriteNormalizationWrapper.cs b/backend/FwLite/MiniLcm/Normalization/MiniLcmApiWriteNormalizationWrapper.cs
index dfb231e83d..a43847bb50 100644
--- a/backend/FwLite/MiniLcm/Normalization/MiniLcmApiWriteNormalizationWrapper.cs
+++ b/backend/FwLite/MiniLcm/Normalization/MiniLcmApiWriteNormalizationWrapper.cs
@@ -532,6 +532,63 @@ public Task DeleteCustomView(Guid id)
 
     #endregion
 
+    #region Comments
+
+    public Task<CommentThread> CreateCommentThread(CommentThread thread, UserComment firstComment)
+    {
+        return _api.CreateCommentThread(thread, NormalizeUserComment(firstComment));
+    }
+
+    public Task<UserComment> AddUserComment(Guid threadId, UserComment comment)
+    {
+        return _api.AddUserComment(threadId, NormalizeUserComment(comment));
+    }
+
+    public Task<UserComment> EditUserComment(Guid commentId, string text)
+    {
+        return _api.EditUserComment(commentId, StringNormalizer.Normalize(text));
+    }
+
+    public Task<CommentThread> SetCommentThreadStatus(Guid threadId, ThreadStatus status)
+    {
+        return _api.SetCommentThreadStatus(threadId, status);
+    }
+
+    public Task DeleteUserComment(Guid commentId)
+    {
+        return _api.DeleteUserComment(commentId);
+    }
+
+    public Task DeleteCommentThread(Guid threadId)
+    {
+        return _api.DeleteCommentThread(threadId);
+    }
+
+    public Task MarkCommentRead(Guid commentId)
+    {
+        return _api.MarkCommentRead(commentId);
+    }
+
+    public Task MarkCommentThreadRead(Guid threadId)
+    {
+        return _api.MarkCommentThreadRead(threadId);
+    }
+
+    public Task MarkAllCommentsRead()
+    {
+        return _api.MarkAllCommentsRead();
+    }
+
+    private static UserComment NormalizeUserComment(UserComment comment)
+    {
+        return comment with
+        {
+            Text = StringNormalizer.Normalize(comment.Text)
+        };
+    }
+
+    #endregion
+
     #region File Operations
 
     public Task<UploadFileResponse> SaveFile(Stream stream, LcmFileMetadata metadata)
diff --git a/frontend/viewer/src/lib/components/ui/input-group/index.ts b/frontend/viewer/src/lib/components/ui/input-group/index.ts
new file mode 100644
index 0000000000..dfde139344
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/index.ts
@@ -0,0 +1,22 @@
+import Root from './input-group.svelte';
+import Addon from './input-group-addon.svelte';
+import Button from './input-group-button.svelte';
+import Input from './input-group-input.svelte';
+import Text from './input-group-text.svelte';
+import Textarea from './input-group-textarea.svelte';
+
+export {
+  Root,
+  Addon,
+  Button,
+  Input,
+  Text,
+  Textarea,
+  //
+  Root as InputGroup,
+  Addon as InputGroupAddon,
+  Button as InputGroupButton,
+  Input as InputGroupInput,
+  Text as InputGroupText,
+  Textarea as InputGroupTextarea,
+};
diff --git a/frontend/viewer/src/lib/components/ui/input-group/input-group-addon.svelte b/frontend/viewer/src/lib/components/ui/input-group/input-group-addon.svelte
new file mode 100644
index 0000000000..8ce9e914ca
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/input-group-addon.svelte
@@ -0,0 +1,52 @@
+<script lang="ts" module>
+  import {tv, type VariantProps} from 'tailwind-variants';
+  export const inputGroupAddonVariants = tv({
+    base: "text-muted-foreground h-auto gap-2 py-1.5 text-sm font-medium group-data-[disabled=true]/input-group:opacity-50 [&>kbd]:rounded-[calc(var(--radius)-5px)] [&>svg:not([class*='size-'])]:size-4 flex cursor-text items-center justify-center select-none",
+    variants: {
+      align: {
+        'inline-start': 'pl-2 has-[>button]:ml-[-0.3rem] has-[>kbd]:ml-[-0.15rem] order-first',
+        'inline-end': 'pr-2 has-[>button]:mr-[-0.3rem] has-[>kbd]:mr-[-0.15rem] order-last',
+        'block-start':
+          'px-2.5 pt-2 group-has-[>input]/input-group:pt-2 [.border-b]:pb-2 order-first w-full justify-start',
+        'block-end': 'px-2.5 pb-2 group-has-[>input]/input-group:pb-2 [.border-t]:pt-2 order-last w-full justify-start',
+      },
+    },
+    defaultVariants: {
+      align: 'inline-start',
+    },
+  });
+
+  export type InputGroupAddonAlign = VariantProps<typeof inputGroupAddonVariants>['align'];
+</script>
+
+<script lang="ts">
+  import {cn, type WithElementRef} from '$lib/utils.js';
+  import type {HTMLAttributes} from 'svelte/elements';
+
+  let {
+    ref = $bindable(null),
+    class: className,
+    children,
+    align = 'inline-start',
+    ...restProps
+  }: WithElementRef<HTMLAttributes<HTMLDivElement>> & {
+    align?: InputGroupAddonAlign;
+  } = $props();
+</script>
+
+<div
+  bind:this={ref}
+  role="group"
+  data-slot="input-group-addon"
+  data-align={align}
+  class={cn(inputGroupAddonVariants({align}), className)}
+  onclick={(e) => {
+    if ((e.target as HTMLElement).closest('button')) {
+      return;
+    }
+    e.currentTarget.parentElement?.querySelector('input')?.focus();
+  }}
+  {...restProps}
+>
+  {@render children?.()}
+</div>
diff --git a/frontend/viewer/src/lib/components/ui/input-group/input-group-button.svelte b/frontend/viewer/src/lib/components/ui/input-group/input-group-button.svelte
new file mode 100644
index 0000000000..57be2a633d
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/input-group-button.svelte
@@ -0,0 +1,48 @@
+<script lang="ts" module>
+  import {tv, type VariantProps} from 'tailwind-variants';
+
+  const inputGroupButtonVariants = tv({
+    base: 'gap-2 text-sm flex items-center shadow-none',
+    variants: {
+      size: {
+        xs: "h-6 gap-1 rounded-[calc(var(--radius)-3px)] px-1.5 [&>svg:not([class*='size-'])]:size-3.5",
+        sm: 'cn-input-group-button-size-sm',
+        'icon-xs': 'size-6 rounded-[calc(var(--radius)-3px)] p-0 has-[>svg]:p-0',
+        'icon-sm': 'size-8 p-0 has-[>svg]:p-0',
+      },
+    },
+    defaultVariants: {
+      size: 'xs',
+    },
+  });
+
+  export type InputGroupButtonSize = VariantProps<typeof inputGroupButtonVariants>['size'];
+</script>
+
+<script lang="ts">
+  import {cn} from '$lib/utils.js';
+  import {Button, type ButtonProps} from '$lib/components/ui/button/index.js';
+
+  let {
+    ref = $bindable(null),
+    class: className,
+    children,
+    type = 'button',
+    variant = 'ghost',
+    size = 'xs',
+    ...restProps
+  }: Omit<ButtonProps, 'href' | 'size'> & {
+    size?: InputGroupButtonSize;
+  } = $props();
+</script>
+
+<Button
+  bind:ref
+  {type}
+  data-size={size}
+  {variant}
+  class={cn(inputGroupButtonVariants({size}), className)}
+  {...restProps}
+>
+  {@render children?.()}
+</Button>
diff --git a/frontend/viewer/src/lib/components/ui/input-group/input-group-input.svelte b/frontend/viewer/src/lib/components/ui/input-group/input-group-input.svelte
new file mode 100644
index 0000000000..d4403f6dd4
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/input-group-input.svelte
@@ -0,0 +1,18 @@
+<script lang="ts">
+  import {cn} from '$lib/utils.js';
+  import type {ComponentProps} from 'svelte';
+  import {Input} from '$lib/components/ui/input/index.js';
+
+  let {ref = $bindable(null), value = $bindable(), class: className, ...props}: ComponentProps<typeof Input> = $props();
+</script>
+
+<Input
+  bind:ref
+  data-slot="input-group-control"
+  class={cn(
+    'rounded-none border-0 bg-transparent shadow-none ring-0 focus-visible:ring-0 disabled:bg-transparent aria-invalid:ring-0 dark:bg-transparent dark:disabled:bg-transparent flex-1',
+    className,
+  )}
+  bind:value
+  {...props}
+/>
diff --git a/frontend/viewer/src/lib/components/ui/input-group/input-group-text.svelte b/frontend/viewer/src/lib/components/ui/input-group/input-group-text.svelte
new file mode 100644
index 0000000000..98491a2602
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/input-group-text.svelte
@@ -0,0 +1,22 @@
+<script lang="ts">
+  import {cn, type WithElementRef} from '$lib/utils.js';
+  import type {HTMLAttributes} from 'svelte/elements';
+
+  let {
+    ref = $bindable(null),
+    class: className,
+    children,
+    ...restProps
+  }: WithElementRef<HTMLAttributes<HTMLSpanElement>> = $props();
+</script>
+
+<span
+  bind:this={ref}
+  class={cn(
+    "text-muted-foreground gap-2 text-sm [&_svg:not([class*='size-'])]:size-4 flex items-center [&_svg]:pointer-events-none",
+    className,
+  )}
+  {...restProps}
+>
+  {@render children?.()}
+</span>
diff --git a/frontend/viewer/src/lib/components/ui/input-group/input-group-textarea.svelte b/frontend/viewer/src/lib/components/ui/input-group/input-group-textarea.svelte
new file mode 100644
index 0000000000..35e60ac244
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/input-group-textarea.svelte
@@ -0,0 +1,23 @@
+<script lang="ts">
+  import {cn} from '$lib/utils.js';
+  import {Textarea} from '$lib/components/ui/textarea/index.js';
+  import type {ComponentProps} from 'svelte';
+
+  let {
+    ref = $bindable(null),
+    value = $bindable(),
+    class: className,
+    ...props
+  }: ComponentProps<typeof Textarea> = $props();
+</script>
+
+<Textarea
+  bind:ref
+  data-slot="input-group-control"
+  class={cn(
+    'rounded-none border-0 bg-transparent py-2 shadow-none ring-0 focus-visible:ring-0 disabled:bg-transparent aria-invalid:ring-0 dark:bg-transparent dark:disabled:bg-transparent flex-1 resize-none',
+    className,
+  )}
+  bind:value
+  {...props}
+/>
diff --git a/frontend/viewer/src/lib/components/ui/input-group/input-group.svelte b/frontend/viewer/src/lib/components/ui/input-group/input-group.svelte
new file mode 100644
index 0000000000..725cef40b7
--- /dev/null
+++ b/frontend/viewer/src/lib/components/ui/input-group/input-group.svelte
@@ -0,0 +1,24 @@
+<script lang="ts">
+  import {cn, type WithElementRef} from '$lib/utils.js';
+  import type {HTMLAttributes} from 'svelte/elements';
+
+  let {
+    ref = $bindable(null),
+    class: className,
+    children,
+    ...props
+  }: WithElementRef<HTMLAttributes<HTMLDivElement>> = $props();
+</script>
+
+<div
+  bind:this={ref}
+  data-slot="input-group"
+  role="group"
+  class={cn(
+    'group/input-group border-input dark:bg-input/30 has-[[data-slot=input-group-control]:focus-visible]:border-ring has-[[data-slot=input-group-control]:focus-visible]:ring-ring/50 has-[[data-slot][aria-invalid=true]]:ring-destructive/20 has-[[data-slot][aria-invalid=true]]:border-destructive dark:has-[[data-slot][aria-invalid=true]]:ring-destructive/40 has-disabled:bg-input/50 dark:has-disabled:bg-input/80 h-8 rounded-lg border transition-colors in-data-[slot=combobox-content]:focus-within:border-inherit in-data-[slot=combobox-content]:focus-within:ring-0 has-disabled:opacity-50 has-[[data-slot=input-group-control]:focus-visible]:ring-3 has-[[data-slot][aria-invalid=true]]:ring-3 has-[>[data-align=block-end]]:h-auto has-[>[data-align=block-end]]:flex-col has-[>[data-align=block-start]]:h-auto has-[>[data-align=block-start]]:flex-col has-[>[data-align=block-end]]:[&>input]:pt-3 has-[>[data-align=block-start]]:[&>input]:pb-3 has-[>[data-align=inline-end]]:[&>input]:pr-1.5 has-[>[data-align=inline-start]]:[&>input]:pl-1.5 relative flex w-full min-w-0 items-center outline-none has-[>textarea]:h-auto',
+    className,
+  )}
+  {...props}
+>
+  {@render children?.()}
+</div>
diff --git a/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmFeatures.ts b/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmFeatures.ts
index fd779582b2..34e48f2f36 100644
--- a/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmFeatures.ts
+++ b/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmFeatures.ts
@@ -12,5 +12,6 @@ export interface IMiniLcmFeatures
 	sync?: boolean;
 	audio?: boolean;
 	customViews?: boolean;
+	comments?: boolean;
 }
 /* eslint-enable */
diff --git a/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmJsInvokable.ts b/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmJsInvokable.ts
index 5fedeb1bfc..805d4a62fb 100644
--- a/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmJsInvokable.ts
+++ b/frontend/viewer/src/lib/dotnet-types/generated-types/FwLiteShared/Services/IMiniLcmJsInvokable.ts
@@ -17,6 +17,10 @@ import type {IEntry} from '../../MiniLcm/Models/IEntry';
 import type {IQueryOptions} from '../../MiniLcm/IQueryOptions';
 import type {IWritingSystem} from '../../MiniLcm/Models/IWritingSystem';
 import type {WritingSystemType} from '../../MiniLcm/Models/WritingSystemType';
+import type {ICommentThread} from '../../MiniLcm/Models/ICommentThread';
+import type {SubjectType} from '../../MiniLcm/Models/SubjectType';
+import type {IUserComment} from '../../MiniLcm/Models/IUserComment';
+import type {ThreadStatus} from '../../MiniLcm/Models/ThreadStatus';
 import type {ICreateEntryOptions} from '../../MiniLcm/ICreateEntryOptions';
 import type {IComplexFormComponent} from '../../MiniLcm/Models/IComplexFormComponent';
 import type {ISense} from '../../MiniLcm/Models/ISense';
@@ -60,6 +64,22 @@ export interface IMiniLcmJsInvokable
 	createCustomView(customView: ICustomView) : Promise<ICustomView>;
 	updateCustomView(customView: ICustomView) : Promise<ICustomView>;
 	deleteCustomView(id: string) : Promise<void>;
+	getCommentThreads(subjectType: SubjectType, subjectId: string, includeComments?: boolean) : Promise<ICommentThread[]>;
+	getCommentThread(id: string) : Promise<ICommentThread | null>;
+	getUserComments(threadId: string) : Promise<IUserComment[]>;
+	getUserComment(id: string) : Promise<IUserComment | null>;
+	getUnreadComments(threadId?: string) : Promise<IUserComment[]>;
+	getUnreadCommentsForSubject(subjectType: SubjectType, subjectId: string) : Promise<IUserComment[]>;
+	countUnreadComments(threadId?: string) : Promise<number>;
+	createCommentThread(thread: ICommentThread, firstComment: IUserComment) : Promise<ICommentThread>;
+	addUserComment(threadId: string, comment: IUserComment) : Promise<IUserComment>;
+	editUserComment(commentId: string, text: string) : Promise<IUserComment>;
+	setCommentThreadStatus(threadId: string, status: ThreadStatus) : Promise<ICommentThread>;
+	deleteUserComment(commentId: string) : Promise<void>;
+	deleteCommentThread(threadId: string) : Promise<void>;
+	markCommentRead(commentId: string) : Promise<void>;
+	markCommentThreadRead(threadId: string) : Promise<void>;
+	markAllCommentsRead() : Promise<void>;
 	createEntry(entry: IEntry, options: ICreateEntryOptions) : Promise<IEntry>;
 	updateEntry(before: IEntry, after: IEntry) : Promise<IEntry>;
 	deleteEntry(id: string) : Promise<void>;
diff --git a/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/ICommentThread.ts b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/ICommentThread.ts
new file mode 100644
index 0000000000..f8d361a928
--- /dev/null
+++ b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/ICommentThread.ts
@@ -0,0 +1,24 @@
+/* eslint-disable */
+//     This code was generated by a Reinforced.Typings tool.
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+
+import type {IObjectWithId} from './IObjectWithId';
+import type {SubjectType} from './SubjectType';
+import type {ThreadStatus} from './ThreadStatus';
+import type {IUserComment} from './IUserComment';
+
+export interface ICommentThread extends IObjectWithId
+{
+	id: string;
+	deletedAt?: string;
+	subjectId: string;
+	subjectType: SubjectType;
+	status: ThreadStatus;
+	authorId?: string;
+	authorName?: string;
+	createdAt: string;
+	updatedAt: string;
+	comments?: IUserComment[];
+}
+/* eslint-enable */
diff --git a/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/IUserComment.ts b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/IUserComment.ts
new file mode 100644
index 0000000000..df3332a396
--- /dev/null
+++ b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/IUserComment.ts
@@ -0,0 +1,20 @@
+/* eslint-disable */
+//     This code was generated by a Reinforced.Typings tool.
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+
+import type {IObjectWithId} from './IObjectWithId';
+
+export interface IUserComment extends IObjectWithId
+{
+	id: string;
+	deletedAt?: string;
+	commentThreadId: string;
+	previousCommentId?: string;
+	text: string;
+	authorId?: string;
+	authorName?: string;
+	createdAt: string;
+	updatedAt: string;
+}
+/* eslint-enable */
diff --git a/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/SubjectType.ts b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/SubjectType.ts
new file mode 100644
index 0000000000..9c12060b92
--- /dev/null
+++ b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/SubjectType.ts
@@ -0,0 +1,12 @@
+/* eslint-disable */
+//     This code was generated by a Reinforced.Typings tool.
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+
+export enum SubjectType {
+	Unknown = "Unknown",
+	Entry = "Entry",
+	Sense = "Sense",
+	ExampleSentence = "ExampleSentence"
+}
+/* eslint-enable */
diff --git a/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/ThreadStatus.ts b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/ThreadStatus.ts
new file mode 100644
index 0000000000..4d088b83f6
--- /dev/null
+++ b/frontend/viewer/src/lib/dotnet-types/generated-types/MiniLcm/Models/ThreadStatus.ts
@@ -0,0 +1,10 @@
+/* eslint-disable */
+//     This code was generated by a Reinforced.Typings tool.
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+
+export enum ThreadStatus {
+	Open = "Open",
+	Closed = "Closed"
+}
+/* eslint-enable */
diff --git a/frontend/viewer/src/lib/dotnet-types/index.ts b/frontend/viewer/src/lib/dotnet-types/index.ts
index 811b6979d1..82ad4deef2 100644
--- a/frontend/viewer/src/lib/dotnet-types/index.ts
+++ b/frontend/viewer/src/lib/dotnet-types/index.ts
@@ -31,6 +31,10 @@ export * from './generated-types/MiniLcm/Models/ICustomView';
 export * from './generated-types/MiniLcm/Models/IViewField';
 export * from './generated-types/MiniLcm/Models/IViewWritingSystem';
 export * from './generated-types/MiniLcm/Models/ViewBase';
+export * from './generated-types/MiniLcm/Models/ICommentThread';
+export * from './generated-types/MiniLcm/Models/IUserComment';
+export * from './generated-types/MiniLcm/Models/SubjectType';
+export * from './generated-types/MiniLcm/Models/ThreadStatus';
 export * from './generated-types/MiniLcm/ICountQueryOptions';
 export * from './generated-types/MiniLcm/ICreateEntryOptions';
 export * from './generated-types/MiniLcm/IExemplarOptions';
diff --git a/frontend/viewer/src/lib/entry-editor/CommentDialog.svelte b/frontend/viewer/src/lib/entry-editor/CommentDialog.svelte
new file mode 100644
index 0000000000..fa187a4c8b
--- /dev/null
+++ b/frontend/viewer/src/lib/entry-editor/CommentDialog.svelte
@@ -0,0 +1,347 @@
+<script lang="ts">
+  import * as Drawer from '$lib/components/ui/drawer';
+  import * as Sheet from '$lib/components/ui/sheet';
+  import * as InputGroup from '$lib/components/ui/input-group';
+  import {Button, buttonVariants} from '$lib/components/ui/button';
+  import {Icon} from '$lib/components/ui/icon';
+  import {Label} from '$lib/components/ui/label';
+  import {Textarea} from '$lib/components/ui/textarea';
+  import {IsMobile} from '$lib/hooks/is-mobile.svelte';
+  import {useMiniLcmApi} from '$lib/services/service-provider';
+  import {useProjectContext} from '$project/project-context.svelte';
+  import {cn, randomId} from '$lib/utils';
+  import type {ICommentThread} from '$lib/dotnet-types/generated-types/MiniLcm/Models/ICommentThread';
+  import type {IUserComment} from '$lib/dotnet-types/generated-types/MiniLcm/Models/IUserComment';
+  import type {SubjectType} from '$lib/dotnet-types/generated-types/MiniLcm/Models/SubjectType';
+  import {ThreadStatus} from '$lib/dotnet-types/generated-types/MiniLcm/Models/ThreadStatus';
+  import type {ClassValue} from 'clsx';
+  import {resource} from 'runed';
+  import {MediaQuery} from 'svelte/reactivity';
+  import {t} from 'svelte-i18n-lingui';
+
+  type ThreadView = {
+    thread: ICommentThread;
+    comments: IUserComment[];
+  };
+
+  let {
+    open = $bindable(false),
+    subjectType,
+    subjectId,
+    subjectName,
+    inlineSidebar = false,
+    class: className,
+  }: {
+    open: boolean;
+    subjectType: SubjectType;
+    subjectId: string;
+    subjectName?: string;
+    inlineSidebar?: boolean;
+    class?: ClassValue;
+  } = $props();
+
+  const api = useMiniLcmApi();
+  const projectContext = useProjectContext();
+  const currentUserId = $derived(projectContext.projectData?.lastUserId);
+  const canComment = $derived(Boolean(currentUserId));
+  const isExtraLarge = new MediaQuery('min-width: 1280px');
+
+  let saving = $state(false);
+  let newThreadText = $state('');
+  let replyTextByThreadId = $state<Record<string, string>>({});
+  let editingCommentId = $state<string>();
+  let editTextByCommentId = $state<Record<string, string>>({});
+
+  const threadsResource = resource(
+    [() => open, () => subjectType, () => subjectId],
+    async ([isOpen, targetSubjectType, targetSubjectId]): Promise<ThreadView[]> => {
+      if (!isOpen) return [];
+      const threads = await api.getCommentThreads(targetSubjectType, targetSubjectId, true);
+      return threads.map((thread) => ({thread, comments: thread.comments ?? []}));
+    },
+    {initialValue: [] satisfies ThreadView[]},
+  );
+  const threadViews = $derived(threadsResource.current);
+  const loading = $derived(threadsResource.loading);
+
+  const title = $derived(subjectName ? $t`Comments for ${subjectName}` : $t`Comments`);
+  const hasThreads = $derived(threadViews.length > 0);
+  const shouldUseSidebar = $derived(inlineSidebar && isExtraLarge.current);
+
+  function onOpenChange(value: boolean): void {
+    open = value;
+  }
+
+  async function startThread(): Promise<void> {
+    const text = newThreadText.trim();
+    if (!text) return;
+
+    saving = true;
+    try {
+      const now = new Date().toISOString();
+      const threadId = randomId();
+      await api.createCommentThread({
+        id: threadId,
+        subjectId,
+        subjectType,
+        status: ThreadStatus.Open,
+        createdAt: now,
+        updatedAt: now,
+      }, {
+        id: randomId(),
+        commentThreadId: threadId,
+        text,
+        createdAt: now,
+        updatedAt: now,
+      });
+      newThreadText = '';
+      await threadsResource.refetch();
+    } finally {
+      saving = false;
+    }
+  }
+
+  async function replyToThread(threadView: ThreadView): Promise<void> {
+    const threadId = threadView.thread.id;
+    const text = replyTextByThreadId[threadId]?.trim();
+    if (!text) return;
+
+    saving = true;
+    try {
+      const now = new Date().toISOString();
+      await api.addUserComment(threadId, {
+        id: randomId(),
+        commentThreadId: threadId,
+        previousCommentId: threadView.comments.at(-1)?.id,
+        text,
+        createdAt: now,
+        updatedAt: now,
+      });
+      replyTextByThreadId[threadId] = '';
+      await threadsResource.refetch();
+    } finally {
+      saving = false;
+    }
+  }
+
+  function startEditing(comment: IUserComment): void {
+    editingCommentId = comment.id;
+    editTextByCommentId[comment.id] = comment.text;
+  }
+
+  function cancelEditing(commentId: string): void {
+    editingCommentId = undefined;
+    delete editTextByCommentId[commentId];
+  }
+
+  async function saveEdit(commentId: string): Promise<void> {
+    const text = editTextByCommentId[commentId]?.trim();
+    if (!text) return;
+
+    saving = true;
+    try {
+      await api.editUserComment(commentId, text);
+      cancelEditing(commentId);
+      await threadsResource.refetch();
+    } finally {
+      saving = false;
+    }
+  }
+
+  function submitOnCtrlEnter(event: KeyboardEvent): void {
+    if (event.key === 'Enter' && event.ctrlKey) {
+      const target = event.target as HTMLTextAreaElement | null;
+      target?.form?.requestSubmit();
+      event.preventDefault();
+    }
+  }
+</script>
+
+{#snippet commentContent()}
+  <div class="flex min-h-0 flex-1 flex-col overflow-hidden">
+    <div class="min-h-0 flex-1 space-y-4 overflow-y-auto px-4 pb-4">
+      <form onsubmit={(e) => { e.preventDefault(); void startThread(); }} class="space-y-2">
+        <Label for="new-comment-thread">{$t`Start a new thread`}</Label>
+        {#if canComment}
+          <InputGroup.Root>
+            <InputGroup.Textarea
+              id="new-comment-thread"
+              bind:value={newThreadText}
+              placeholder={$t`Write the first comment...`}
+              rows={2}
+              disabled={loading || saving}
+              onkeydown={submitOnCtrlEnter}
+              class="min-h-4 py-1"
+            />
+            <InputGroup.Addon align="block-end" class="flex-row-reverse">
+              <InputGroup.Button
+                variant="default"
+                size="icon-xs"
+                icon="i-mdi-send"
+                class="p-0! [&>.icon-wrapper]:flex [&>.icon-wrapper]:items-center [&>.icon-wrapper]:justify-center"
+                iconProps={{ class: 'size-4' }}
+                type="submit" disabled={!newThreadText.trim() || loading} loading={saving}
+              />
+            </InputGroup.Addon>
+          </InputGroup.Root>
+        {:else}
+          <p class="rounded-md border border-dashed p-3 text-sm text-muted-foreground">
+            {$t`Sign in to add comments.`}
+          </p>
+        {/if}
+      </form>
+
+      <div class="space-y-3">
+        {#if loading}
+          <p class="text-sm text-muted-foreground">{$t`Loading comments...`}</p>
+        {:else if !hasThreads}
+          <p class="rounded-md border border-dashed p-4 text-sm text-muted-foreground">
+            {$t`No comment threads yet.`}
+          </p>
+        {:else}
+          {#each threadViews as threadView (threadView.thread.id)}
+            <section class="space-y-3 rounded-md border p-3">
+              <div class="flex items-center justify-between gap-2">
+                <div class="min-w-0">
+                  <h3 class="text-sm font-semibold">{$t`Thread`}</h3>
+                  <span class="text-xs text-muted-foreground">
+                    {threadView.thread.authorName || $t`(unknown)`}
+                  </span>
+                </div>
+                <span class="shrink-0 text-xs text-muted-foreground">
+                  {threadView.thread.status === ThreadStatus.Closed ? $t`Closed` : $t`Open`}
+                </span>
+              </div>
+
+              <div class="space-y-2">
+                {#each threadView.comments as comment (comment.id)}
+                  <article class="rounded-md bg-muted/60 p-3">
+                    <div class="mb-2 flex items-center justify-between gap-2">
+                      <span class="text-xs font-medium text-muted-foreground">
+                        {comment.authorName || $t`(unknown)`}
+                      </span>
+                      {#if currentUserId && comment.authorId === currentUserId}
+                        <Button
+                          variant="ghost"
+                          size="xs"
+                          onclick={() => startEditing(comment)}
+                          disabled={saving || editingCommentId === comment.id}
+                        >
+                          {$t`Edit`}
+                        </Button>
+                      {/if}
+                    </div>
+
+                    {#if editingCommentId === comment.id}
+                      <div class="space-y-2">
+                        <Textarea
+                          bind:value={editTextByCommentId[comment.id]}
+                          aria-label={$t`Edit comment`}
+                          rows={3}
+                          disabled={saving}
+                        />
+                        <div class="flex justify-end gap-2">
+                          <Button variant="secondary" size="sm" onclick={() => cancelEditing(comment.id)} disabled={saving}>
+                            {$t`Cancel`}
+                          </Button>
+                          <Button
+                            size="sm"
+                            onclick={() => void saveEdit(comment.id)}
+                            disabled={!editTextByCommentId[comment.id]?.trim()}
+                            loading={saving}
+                          >
+                            {$t`Save`}
+                          </Button>
+                        </div>
+                      </div>
+                    {:else}
+                      <p class={cn('whitespace-pre-wrap text-sm', !comment.text && 'text-muted-foreground')}>
+                        {comment.text || $t`Empty comment`}
+                      </p>
+                    {/if}
+                  </article>
+                {/each}
+              </div>
+
+              <div class="space-y-2">
+                {#if canComment}
+                  <form onsubmit={(e) => { e.preventDefault(); void replyToThread(threadView); }} class="space-y-2">
+                    <InputGroup.Root>
+                      <InputGroup.Textarea
+                        id={`reply-${threadView.thread.id}`}
+                        bind:value={replyTextByThreadId[threadView.thread.id]}
+                        placeholder={$t`Write a reply...`}
+                        class="min-h-4 py-1"
+                        rows={1}
+                        disabled={saving}
+                        onkeydown={submitOnCtrlEnter}
+                      />
+                      <InputGroup.Addon align="block-end" class="flex-row-reverse">
+                        <InputGroup.Button
+                          variant="ghost"
+                          size="icon-xs"
+                          icon="i-mdi-send"
+                          class="p-0! [&>.icon-wrapper]:flex [&>.icon-wrapper]:items-center [&>.icon-wrapper]:justify-center"
+                          iconProps={{ class: 'size-4' }}
+                          type="submit"
+                          disabled={!replyTextByThreadId[threadView.thread.id]?.trim()}
+                          loading={saving}
+                        />
+                      </InputGroup.Addon>
+                    </InputGroup.Root>
+                  </form>
+                {/if}
+              </div>
+            </section>
+          {/each}
+        {/if}
+      </div>
+    </div>
+  </div>
+{/snippet}
+
+{#if shouldUseSidebar && open}
+  <aside
+    class={cn(
+      'flex h-full min-h-0 w-96 shrink-0 flex-col overflow-hidden rounded-lg border bg-background shadow-sm',
+      className,
+    )}
+  >
+    <div class="flex items-start gap-2 px-4 pt-4 pb-0">
+      <div class="min-w-0 flex-1">
+        <h2 class="truncate text-lg font-semibold" title={title}>{title}</h2>
+      </div>
+      <Button variant="ghost" size="icon" aria-label={$t`Close`} onclick={() => onOpenChange(false)}>
+        <Icon icon="i-mdi-close" />
+      </Button>
+    </div>
+    {@render commentContent()}
+  </aside>
+{:else if IsMobile.value}
+  <Drawer.Root bind:open={() => open, onOpenChange}>
+    <Drawer.Content class="max-h-[90dvh] overflow-hidden">
+      <Drawer.Close
+        class={buttonVariants({variant: 'ghost', size: 'icon', class: 'absolute top-4 right-4 z-10'})}
+        aria-label={$t`Close`}
+      >
+        <Icon icon="i-mdi-close" />
+      </Drawer.Close>
+
+      <div class="mx-auto flex max-h-[90dvh] w-full max-w-lg flex-1 flex-col overflow-hidden">
+        <Drawer.Header class="px-4 text-left">
+          <Drawer.Title class="max-w-[calc(100%-2rem)] truncate pr-2 text-left" title={title}>{title}</Drawer.Title>
+        </Drawer.Header>
+        {@render commentContent()}
+      </div>
+    </Drawer.Content>
+  </Drawer.Root>
+{:else}
+  <Sheet.Root bind:open={() => open, onOpenChange}>
+    <Sheet.Content side="right" class="w-full overflow-hidden p-0 sm:max-w-md">
+      <Sheet.Header class="px-4 pb-0">
+        <Sheet.Title class="max-w-[calc(100%-2rem)] truncate pr-2" title={title}>{title}</Sheet.Title>
+      </Sheet.Header>
+      {@render commentContent()}
+    </Sheet.Content>
+  </Sheet.Root>
+{/if}
diff --git a/frontend/viewer/src/lib/entry-editor/EntityListItemActions.svelte b/frontend/viewer/src/lib/entry-editor/EntityListItemActions.svelte
index ae9243ea49..9f6bbba5b6 100644
--- a/frontend/viewer/src/lib/entry-editor/EntityListItemActions.svelte
+++ b/frontend/viewer/src/lib/entry-editor/EntityListItemActions.svelte
@@ -27,6 +27,7 @@
   const features = useFeatures();
 
   let showHistoryView = $state(false);
+  const item = $derived(items[i]);
 </script>
 
 {#if !readonly || features.history}
@@ -34,7 +35,7 @@
   {#if !readonly}
     <Reorderer
       direction="vertical"
-      item={items[i]}
+      {item}
       {items}
       {getDisplayName}
       onchange={(_newItems, _fromIndex, newIndex) => onmove?.(newIndex)}
diff --git a/frontend/viewer/src/lib/entry-editor/object-editors/EntryEditor.svelte b/frontend/viewer/src/lib/entry-editor/object-editors/EntryEditor.svelte
index 655ffef4f0..aaa36c051b 100644
--- a/frontend/viewer/src/lib/entry-editor/object-editors/EntryEditor.svelte
+++ b/frontend/viewer/src/lib/entry-editor/object-editors/EntryEditor.svelte
@@ -1,4 +1,6 @@
 <script lang="ts" module>
+  import type {IEntry, IExampleSentence, ISense} from '$lib/dotnet-types';
+
   export type Props = {
     entry: IEntry;
     readonly?: boolean;
@@ -12,7 +14,6 @@
   };
 </script>
 <script lang="ts">
-  import type {IEntry, IExampleSentence, ISense} from '$lib/dotnet-types';
   import {useDialogsService} from '$lib/services/dialogs-service';
   import {useViewService, hasVisibleFields} from '$lib/views/view-service.svelte';
   import {cn, defaultExampleSentence, defaultSense} from '$lib/utils';
@@ -167,9 +168,10 @@
   const showSenses = $derived(showExamples || hasVisibleFields(viewService.currentView.senseFields));
 </script>
 
-<Editor.Root bind:ref bind:this={editor}>
-  <Editor.Grid bind:ref={editorElem}>
-    <EntryEditorPrimitive class={ENTITY_FIELD_CONTAINER_CLASS} bind:entry {readonly} {autofocus} {modalMode} onchange={(entry) => onchange?.({entry})} />
+<div class="flex min-h-0 gap-4">
+  <Editor.Root bind:ref bind:this={editor} class="min-w-0 flex-1">
+    <Editor.Grid bind:ref={editorElem}>
+      <EntryEditorPrimitive class={ENTITY_FIELD_CONTAINER_CLASS} bind:entry {readonly} {autofocus} {modalMode} onchange={(entry) => onchange?.({entry})} />
 
     {#if showSenses}
       {#each entry.senses as sense, i (sense.id)}
@@ -195,11 +197,11 @@
                   <div id="example{i + 1}-{j + 1}"></div> <!-- shouldn't be in the sticky header -->
                   <ObjectHeader type="example" index={j + 1}>
                     <EntityListItemActions i={j} {readonly}
-                                          items={sense.exampleSentences}
-                                          getDisplayName={example => writingSystemService.firstSentenceOrTranslationVal(example)}
-                                          onmove={(newIndex) => moveExample(sense, example, newIndex)}
-                                          ondelete={() => deleteExample(sense, example)}
-                                          id={example.id} />
+                                           items={sense.exampleSentences}
+                                           getDisplayName={example => writingSystemService.firstSentenceOrTranslationVal(example)}
+                                           onmove={(newIndex) => moveExample(sense, example, newIndex)}
+                                           ondelete={() => deleteExample(sense, example)}
+                                           id={example.id}/>
                   </ObjectHeader>
 
                   <ExampleEditorPrimitive
@@ -243,8 +245,9 @@
         </code>
       </details>
     </DevContent>
-  </Editor.Grid>
-</Editor.Root>
+    </Editor.Grid>
+  </Editor.Root>
+</div>
 
 <style lang="postcss">
   @reference "#app.css";
diff --git a/frontend/viewer/src/lib/services/feature-service.ts b/frontend/viewer/src/lib/services/feature-service.ts
index a52719526b..6e8ed8cc9d 100644
--- a/frontend/viewer/src/lib/services/feature-service.ts
+++ b/frontend/viewer/src/lib/services/feature-service.ts
@@ -8,22 +8,28 @@ export function useFeatures(): LexboxFeatures {
   //need to do this as returning context.features would not be reactive
   return {
     get history() {
-      return context.features.history;
+      return !!context.features.history;
     },
     get feedback() {
-      return context.features.feedback;
+      return !!context.features.feedback;
     },
     get openWithFlex() {
-      return context.features.openWithFlex;
+      return !!context.features.openWithFlex;
     },
     get sync() {
-      return context.features.sync;
+      return !!context.features.sync;
     },
     get write() {
-      return context.features.write;
+      return !!context.features.write;
     },
     get audio() {
-      return context.features.audio;
-    }
-  };
+      return !!context.features.audio;
+    },
+    get comments() {
+      return !!context.features.comments;
+    },
+    get customViews() {
+      return !!context.features.customViews;
+    },
+  } satisfies Required<IMiniLcmFeatures>;
 }
diff --git a/frontend/viewer/src/locales/en.po b/frontend/viewer/src/locales/en.po
index 6b84bbad2d..492a91a935 100644
--- a/frontend/viewer/src/locales/en.po
+++ b/frontend/viewer/src/locales/en.po
@@ -20,6 +20,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} changes)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr "(unknown)"
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -340,6 +344,7 @@ msgstr "Browse view failed"
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -389,6 +394,8 @@ msgstr "clear"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Close"
@@ -399,6 +406,10 @@ msgstr "Close"
 msgid "Close Dictionary"
 msgstr "Close Dictionary"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr "Closed"
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -409,6 +420,15 @@ msgstr "Code"
 msgid "Color"
 msgstr "Color"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr "Comments"
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr "Comments for {0}"
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -702,6 +722,14 @@ msgstr "Downloading..."
 msgid "e.g. th, sw"
 msgstr "e.g. th, sw"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr "Edit"
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr "Edit comment"
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -712,6 +740,10 @@ msgstr "Edit Custom View"
 msgid "Editor"
 msgstr "Editor"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr "Empty comment"
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -873,7 +905,7 @@ msgstr "FieldWorks Lite version"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1157,6 +1189,10 @@ msgstr "Literal meaning"
 msgid "Loading activity"
 msgstr "Loading activity"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr "Loading comments..."
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1370,6 +1406,10 @@ msgstr "No audio"
 msgid "No authors"
 msgstr "No authors"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr "No comment threads yet."
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1496,6 +1536,7 @@ msgstr "One FieldWorks Classic commit may consist of changes to multiple entries
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Open"
 
@@ -1700,6 +1741,10 @@ msgstr "Review"
 msgid "rose"
 msgstr "rose"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr "Save"
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1828,6 +1873,10 @@ msgstr "Show"
 msgid "Show {0} more..."
 msgstr "Show {0} more..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr "Sign in to add comments."
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1852,6 +1901,10 @@ msgstr "Something went wrong"
 msgid "Specific field"
 msgstr "Specific field"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr "Start a new thread"
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2032,6 +2085,10 @@ msgstr "This task is complete"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr "Thread"
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2091,10 +2148,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "Unable to open in FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2269,6 +2323,14 @@ msgstr "Word or Display as is required"
 msgid "Word or meaning:"
 msgstr "Word or meaning:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr "Write a reply..."
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr "Write the first comment..."
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/es.po b/frontend/viewer/src/locales/es.po
index 4466e176aa..7ea9a0cc57 100644
--- a/frontend/viewer/src/locales/es.po
+++ b/frontend/viewer/src/locales/es.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} cambios)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "borrar"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Cerrar"
@@ -404,6 +411,10 @@ msgstr "Cerrar"
 msgid "Close Dictionary"
 msgstr "Cerrar Diccionario"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "Color"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "Descargando..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "Editar vista personalizada"
 msgid "Editor"
 msgstr "Editor"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "Versión de FieldWorks Lite"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "Significado literal"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "Sin audio"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "Un commit de FieldWorks Classic puede consistir en cambios en múltiples
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Abrir"
 
@@ -1705,6 +1746,10 @@ msgstr "Revisión"
 msgid "rose"
 msgstr "rosa"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "Mostrar"
 msgid "Show {0} more..."
 msgstr "Mostrar {0} más..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "Campo específico"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "Esta tarea está completa"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "Esto sincronizará las copias de FieldWorks Lite y FieldWorks Classic de su proyecto en Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "No se puede abrir en FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "Se requiere Palabra o Mostrar como"
 msgid "Word or meaning:"
 msgstr "Palabra o significado:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/fr.po b/frontend/viewer/src/locales/fr.po
index 11ac66807a..96692ea385 100644
--- a/frontend/viewer/src/locales/fr.po
+++ b/frontend/viewer/src/locales/fr.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} changements)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "effacer"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Fermer"
@@ -404,6 +411,10 @@ msgstr "Fermer"
 msgid "Close Dictionary"
 msgstr "Fermer le dictionnaire"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "Couleur"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "Téléchargement en cours..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "Modifier la vue personnalisée"
 msgid "Editor"
 msgstr "Editeur"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "Version de FieldWorks Lite"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "Sens littéral"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "Aucun contenu audio"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "Un commit FieldWorks Classic peut contenir des modifications à plusieur
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Ouvert"
 
@@ -1705,6 +1746,10 @@ msgstr "Évaluer"
 msgid "rose"
 msgstr "rose"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "Afficher"
 msgid "Show {0} more..."
 msgstr "Afficher {0} plus..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "Champ spécifique"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "Cette tâche est terminée"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "Cela synchronisera les copies FieldWorks Lite et FieldWorks Classic de votre projet dans Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "Impossible d'ouvrir FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "Mot ou affichage tel que requis"
 msgid "Word or meaning:"
 msgstr "Mot ou sens :"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/id.po b/frontend/viewer/src/locales/id.po
index cc4db4c822..ea708ce4b4 100644
--- a/frontend/viewer/src/locales/id.po
+++ b/frontend/viewer/src/locales/id.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "- ({0} perubahan)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "jelas"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Tutup"
@@ -404,6 +411,10 @@ msgstr "Tutup"
 msgid "Close Dictionary"
 msgstr "Tutup Kamus"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "Warna"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "Mengunduh..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "Edit Tampilan Khusus"
 msgid "Editor"
 msgstr "Editor"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "Versi FieldWorks Lite"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "Arti harfiah"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "Tidak ada audio"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "Satu komit FieldWorks Classic dapat terdiri dari perubahan pada beberapa
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Buka"
 
@@ -1705,6 +1746,10 @@ msgstr "Ulasan"
 msgid "rose"
 msgstr "naik"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "Tampilkan"
 msgid "Show {0} more..."
 msgstr "Tampilkan {0} selengkapnya..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "Bidang tertentu"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "Tugas ini selesai"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "Ini akan menyinkronkan salinan FieldWorks Lite dan FieldWorks Classic dari proyek Anda di Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "Tidak dapat dibuka di FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "Kata atau Tampilan sesuai kebutuhan"
 msgid "Word or meaning:"
 msgstr "Kata atau makna:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/ko.po b/frontend/viewer/src/locales/ko.po
index 463bc45c15..8730588f46 100644
--- a/frontend/viewer/src/locales/ko.po
+++ b/frontend/viewer/src/locales/ko.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "- ({0}개 변경)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "clear"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "닫기"
@@ -404,6 +411,10 @@ msgstr "닫기"
 msgid "Close Dictionary"
 msgstr "사전 닫기"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "색상"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "다운로드 중..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "사용자 지정 보기 편집"
 msgid "Editor"
 msgstr "편집기"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "FieldWorks Lite 버전"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "문자 그대로의 의미"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "오디오 없음"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "하나의 FieldWorks Classic 커밋은 여러 항목 또는 필드에 
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "열기"
 
@@ -1705,6 +1746,10 @@ msgstr "검토"
 msgid "rose"
 msgstr "rose"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "표시"
 msgid "Show {0} more..."
 msgstr "보기 {0} 더보기..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "특정 필드"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "이 작업이 완료되었습니다."
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "이렇게 하면 렉스박스에서 프로젝트의 FieldWorks Lite 및 FieldWorks Classic 사본이 동기화됩니다."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "FieldWorks에서 열 수 없음"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "단어 또는 표시 이름은 필수 입력 사항입니다."
 msgid "Word or meaning:"
 msgstr "단어 또는 의미:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/ms.po b/frontend/viewer/src/locales/ms.po
index 99a2ba01ca..322624da51 100644
--- a/frontend/viewer/src/locales/ms.po
+++ b/frontend/viewer/src/locales/ms.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} perubahan)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "padam"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Tutup"
@@ -404,6 +411,10 @@ msgstr "Tutup"
 msgid "Close Dictionary"
 msgstr "Tutup Kamus"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "Warna"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "Memuat turun..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "Sunting Tinjauan Tersuai"
 msgid "Editor"
 msgstr "Editor"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "Versi FieldWorks Lite"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "Makna harfiah"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "Tiada audio"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "Satu komit FieldWorks Classic mungkin terdiri daripada perubahan pada be
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Buka"
 
@@ -1705,6 +1746,10 @@ msgstr "Semak"
 msgid "rose"
 msgstr "merah jambu"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "Tunjukkan"
 msgid "Show {0} more..."
 msgstr "Tunjukkan {0} lagi..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "Medan tertentu"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "Tugasan ini selesai"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "Ini akan menyegerakkan salinan FieldWorks Lite dan FieldWorks Classic projek anda dalam Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "Tidak dapat membuka dalam FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "Perkataan atau Papar Sebagai diperlukan"
 msgid "Word or meaning:"
 msgstr "Perkataan atau makna:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/sw.po b/frontend/viewer/src/locales/sw.po
index 2dd287849e..dfb9372ea5 100644
--- a/frontend/viewer/src/locales/sw.po
+++ b/frontend/viewer/src/locales/sw.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} mabadiliko)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "futa"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Funga"
@@ -404,6 +411,10 @@ msgstr "Funga"
 msgid "Close Dictionary"
 msgstr "Funga Kamusi"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "Rangi"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "Inapakua..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "Hariri Muonekano Binafsi"
 msgid "Editor"
 msgstr "Mhariri"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "Toleo la FieldWorks Lite"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "Maana halisi"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "Hakuna sauti"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "Kumbuka moja ya FieldWorks Classic inaweza kuwa na mabadiliko kwa ingizo
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Fungua"
 
@@ -1705,6 +1746,10 @@ msgstr "Tathmini"
 msgid "rose"
 msgstr "waridi"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "Onyesha"
 msgid "Show {0} more..."
 msgstr "Onyesha {0} zaidi..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "Sehemu mahsusi"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "Jukumu hili limekamilika"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "Hii itaoanisha kopia za FieldWorks Lite na FieldWorks Classic za mradi wako kwenye Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "Haiwezi kufungua katika FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "Neno au Onyesha kulingana na inavyohitajika"
 msgid "Word or meaning:"
 msgstr "Neno au maana:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/locales/vi.po b/frontend/viewer/src/locales/vi.po
index 8a88c9fac6..ff639574b5 100644
--- a/frontend/viewer/src/locales/vi.po
+++ b/frontend/viewer/src/locales/vi.po
@@ -25,6 +25,10 @@ msgstr ""
 msgid "– ({0} changes)"
 msgstr "– ({0} thay đổi)"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "(unknown)"
+msgstr ""
+
 #. Generic placeholder for dynamic content
 #: src/home/HomeView.svelte
 #: src/lib/components/audio/audio-editor.svelte
@@ -345,6 +349,7 @@ msgstr ""
 #: src/lib/components/SubmitOrCancel.svelte
 #: src/lib/components/audio/AudioDialog.svelte
 #: src/lib/components/field-editors/select.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/lib/entry-editor/EditEntryDialog.svelte
 #: src/lib/entry-editor/NewEntryDialog.svelte
 #: src/lib/views/custom/CustomViewForm.svelte
@@ -394,6 +399,8 @@ msgstr "xóa"
 #: src/lib/about/AboutDialog.svelte
 #: src/lib/components/field-editors/multi-select.svelte
 #: src/lib/components/ui/button/x-button.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 #: src/project/tasks/SubjectPopup.svelte
 msgid "Close"
 msgstr "Đóng"
@@ -404,6 +411,10 @@ msgstr "Đóng"
 msgid "Close Dictionary"
 msgstr "Đóng Từ điển"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Closed"
+msgstr ""
+
 #. Field label in the create-project dialog. The project's short machine-readable identifier (slug), e.g. "my-dictionary".
 #: src/home/CreateProjectDialog.svelte
 msgid "Code"
@@ -414,6 +425,15 @@ msgstr ""
 msgid "Color"
 msgstr "Màu sắc"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+#: src/project/browse/EntryView.svelte
+msgid "Comments"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Comments for {0}"
+msgstr ""
+
 #. Field label
 #: src/lib/entry-editor/field-editors/ComplexFormComponents.svelte
 #: src/lib/entry-editor/field-editors/ComplexForms.svelte
@@ -707,6 +727,14 @@ msgstr "Đang tải xuống..."
 msgid "e.g. th, sw"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit"
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Edit comment"
+msgstr ""
+
 #. Dialog title when editing an existing custom view.
 #: src/lib/views/custom/EditCustomViewDialog.svelte
 msgid "Edit Custom View"
@@ -717,6 +745,10 @@ msgstr "Chỉnh sửa chế độ xem tùy chỉnh"
 msgid "Editor"
 msgstr "Biên tập viên"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Empty comment"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields ending with the search term
 #. Related operators: "Starts with", "Contains", "Equals"
@@ -878,7 +910,7 @@ msgstr "Phiên bản FieldWorks Lite"
 
 #. Alt text for FieldWorks logo image
 #: src/home/HomeView.svelte
-#: src/lib/activity/ActivityFilter.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/components/OpenInFieldWorksButton.svelte
 #: src/project/ProjectDropdown.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -1162,6 +1194,10 @@ msgstr "Ý nghĩa đen"
 msgid "Loading activity"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Loading comments..."
+msgstr ""
+
 #. Loading state text shown in the project/dictionary dropdown while the list of dictionaries is being fetched.
 #: src/project/ProjectDropdown.svelte
 msgid "Loading Dictionaries..."
@@ -1375,6 +1411,10 @@ msgstr "Không có âm thanh"
 msgid "No authors"
 msgstr ""
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "No comment threads yet."
+msgstr ""
+
 #. Empty state message in the manage custom views dialog when none exist.
 #: src/lib/views/custom/ManageCustomViewsDialog.svelte
 msgid "No custom views yet."
@@ -1501,6 +1541,7 @@ msgstr "Một commit của FieldWorks Classic có thể gồm các thay đổi t
 
 #. Button to open downloaded project
 #: src/home/Server.svelte
+#: src/lib/entry-editor/CommentDialog.svelte
 msgid "Open"
 msgstr "Mở"
 
@@ -1705,6 +1746,10 @@ msgstr "Xem lại"
 msgid "rose"
 msgstr "hoa hồng"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Save"
+msgstr ""
+
 #. Dialog button to save audio with new name
 #: src/lib/components/field-editors/audio-input.svelte
 msgid "Save As"
@@ -1833,6 +1878,10 @@ msgstr "Hiển thị"
 msgid "Show {0} more..."
 msgstr "Hiển thị thêm {0}..."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Sign in to add comments."
+msgstr ""
+
 #. View option
 #: src/project/browse/EntryListViewOptions.svelte
 msgid "Simple"
@@ -1857,6 +1906,10 @@ msgstr ""
 msgid "Specific field"
 msgstr "Trường cụ thể"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Start a new thread"
+msgstr ""
+
 #. Filter operator
 #. Search operator: matches fields beginning with the search term
 #. Related operators: "Contains", "Ends with", "Equals"
@@ -2037,6 +2090,10 @@ msgstr "Nhiệm vụ này đã hoàn thành"
 msgid "This will synchronize the FieldWorks Lite and FieldWorks Classic copies of your project in Lexbox."
 msgstr "Điều này sẽ đồng bộ các bản sao FieldWorks Lite và FieldWorks Classic của dự án của bạn trong Lexbox."
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Thread"
+msgstr ""
+
 #. Button to show/hide filter panel
 #: src/project/browse/SearchFilter.svelte
 msgid "Toggle filters"
@@ -2096,10 +2153,7 @@ msgid "Unable to open in FieldWorks"
 msgstr "Không thể mở trong FieldWorks"
 
 #. Fallback value shown when author name or last-change date is unavailable (e.g., in activity history or the sync panel).
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityFilter.svelte
-#: src/lib/activity/ActivityItem.svelte
-#: src/lib/activity/ActivityView.svelte
+#: src/lib/activity/AuthorLabel.svelte
 #: src/lib/activity/utils.ts
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
 #: src/project/sync/FwLiteToFwMergeDetails.svelte
@@ -2274,6 +2328,14 @@ msgstr "Từ hoặc Hiển thị như là bắt buộc."
 msgid "Word or meaning:"
 msgstr "Từ hoặc ý nghĩa:"
 
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write a reply..."
+msgstr ""
+
+#: src/lib/entry-editor/CommentDialog.svelte
+msgid "Write the first comment..."
+msgstr ""
+
 #. Column header
 #: src/project/browse/filter/WsSelect.svelte
 msgid "Writing System"
diff --git a/frontend/viewer/src/project/browse/EntryView.svelte b/frontend/viewer/src/project/browse/EntryView.svelte
index bc302fd4a0..99919ce4c2 100644
--- a/frontend/viewer/src/project/browse/EntryView.svelte
+++ b/frontend/viewer/src/project/browse/EntryView.svelte
@@ -25,6 +25,9 @@
   import {pt} from '$lib/views/view-text';
   import {useViewService} from '$lib/views/view-service.svelte';
   import {useProjectStorage} from '$lib/storage/project-storage.svelte';
+  import CommentDialog from '$lib/entry-editor/CommentDialog.svelte';
+  import {SubjectType} from '$lib/dotnet-types/generated-types/MiniLcm/Models/SubjectType';
+  import DevContent from '$lib/layout/DevContent.svelte';
 
   type DictionaryPreviewMode = 'show' | 'hide' | 'sticky';
 
@@ -104,6 +107,7 @@
 
   let readonly = $state(false);
   let deleted = $state(false);
+  let showCommentDialog = $state(false);
 
   const loadedEntryId = $derived(entry?.id);
   let entryScrollViewportRef: HTMLElement | null = $state(null);
@@ -136,6 +140,17 @@
         {/if}
         <h2 class="ml-4 text-2xl font-semibold mb-2 inline">{headword}</h2>
         <div class="flex">
+          <DevContent>
+            {#if features.comments}
+              <Button
+                variant="ghost"
+                size="icon"
+                icon="i-mdi-comment-text-outline"
+                aria-label={$t`Comments`}
+                onclick={() => showCommentDialog = !showCommentDialog}
+              />
+            {/if}
+          </DevContent>
           <ViewPicker bind:dictionaryPreview={() => dictionaryPreview, (v) => void dictionaryPreviewStorage.set(v)} bind:readonly />
           <EntryMenu {entry} />
         </div>
@@ -158,29 +173,42 @@
           </Alert.Root>
         </div>
       {/if}
-      {#if dictionaryPreview === 'sticky'}
-        <div class="md:px-2">
-          {@render preview(entry)}
-        </div>
-      {/if}
     </header>
-    <ScrollArea bind:viewportRef={entryScrollViewportRef} class={cn('grow md:pr-2')}>
-      {#if dictionaryPreview === 'show'}
-        <div class="md:pl-2">
-          {@render preview(entry)}
-        </div>
-      {/if}
-      <div class="max-md:p-2 md:pt-1 md:pb-2 md:px-2">
-        {#key entry.id}
-          <EntryEditor
-            bind:this={editor}
-            bind:ref={editorRef}
-            bind:entry
-            readonly={readonly || !features.write || deleted}
-            {...entryPersistence.entryEditorProps} />
-        {/key}
+    <div class="flex min-h-0 grow gap-4">
+      <div class="flex min-h-0 min-w-0 grow flex-col">
+        {#if dictionaryPreview === 'sticky'}
+          <div class="shrink-0 md:px-2">
+            {@render preview(entry)}
+          </div>
+        {/if}
+        <ScrollArea bind:viewportRef={entryScrollViewportRef} class={cn('min-w-0 grow md:pr-2')}>
+          {#if dictionaryPreview === 'show'}
+            <div class="md:pl-2">
+              {@render preview(entry)}
+            </div>
+          {/if}
+          <div class="max-md:p-2 md:pt-1 md:pb-2 md:px-2">
+            {#key entry.id}
+              <EntryEditor
+                bind:this={editor}
+                bind:ref={editorRef}
+                bind:entry
+                readonly={readonly || !features.write || deleted}
+                {...entryPersistence.entryEditorProps} />
+            {/key}
+          </div>
+        </ScrollArea>
       </div>
-    </ScrollArea>
+      {#if showCommentDialog}
+        <CommentDialog
+          bind:open={showCommentDialog}
+          inlineSidebar
+          subjectType={SubjectType.Entry}
+          subjectId={entry.id}
+          subjectName={headword}
+        />
+      {/if}
+    </div>
   {/if}
   {#if loadingDebounced.current && entryResource.current?.id !== entryId}
     <div
diff --git a/frontend/viewer/src/project/demo/in-memory-demo-api.ts b/frontend/viewer/src/project/demo/in-memory-demo-api.ts
index 7eb2bbbf33..cfa42ed2e1 100644
--- a/frontend/viewer/src/project/demo/in-memory-demo-api.ts
+++ b/frontend/viewer/src/project/demo/in-memory-demo-api.ts
@@ -45,6 +45,10 @@ import {type EventBus, useEventBus, ProjectEventBus} from '$lib/services/event-b
 import type {IJsEventListener} from '$lib/dotnet-types/generated-types/FwLiteShared/Events/IJsEventListener';
 import {initProjectStorage} from '$lib/storage';
 import {MorphTypesService} from '$project/data/morph-types.svelte';
+import type {ICommentThread} from '$lib/dotnet-types/generated-types/MiniLcm/Models/ICommentThread';
+import type {IUserComment} from '$lib/dotnet-types/generated-types/MiniLcm/Models/IUserComment';
+import type {SubjectType} from '$lib/dotnet-types/generated-types/MiniLcm/Models/SubjectType';
+import type {ThreadStatus} from '$lib/dotnet-types/generated-types/MiniLcm/Models/ThreadStatus';
 
 function pickWs(ws: string, defaultWs: string): string {
   return ws === 'default' ? defaultWs : ws;
@@ -202,6 +206,137 @@ export class InMemoryDemoApi implements IMiniLcmJsInvokable {
 
   readonly projectName = projectName;
 
+  private _commentThreads: ICommentThread[] = [];
+  private _userComments: IUserComment[] = [];
+
+  getCommentThreads(subjectType: SubjectType, subjectId: string, includeComments = false): Promise<ICommentThread[]> {
+    return Promise.resolve(this._commentThreads
+      .filter(thread => !thread.deletedAt && thread.subjectType === subjectType && thread.subjectId === subjectId)
+      .map(thread => ({
+        ...thread,
+        comments: includeComments
+          ? this._userComments.filter(comment => !comment.deletedAt && comment.commentThreadId === thread.id).map(comment => ({...comment}))
+          : undefined,
+      })));
+  }
+
+  getCommentThread(id: string): Promise<ICommentThread | null> {
+    const thread = this._commentThreads.find(thread => thread.id === id && !thread.deletedAt);
+    return Promise.resolve(thread ? {...thread} : null);
+  }
+
+  getUserComments(threadId: string): Promise<IUserComment[]> {
+    return Promise.resolve(this._userComments
+      .filter(comment => !comment.deletedAt && comment.commentThreadId === threadId)
+      .map(comment => ({...comment})));
+  }
+
+  getUserComment(id: string): Promise<IUserComment | null> {
+    const comment = this._userComments.find(comment => comment.id === id && !comment.deletedAt);
+    return Promise.resolve(comment ? {...comment} : null);
+  }
+
+  getUnreadComments(_threadId?: string): Promise<IUserComment[]> {
+    return Promise.resolve([]);
+  }
+
+  getUnreadCommentsForSubject(_subjectType: SubjectType, _subjectId: string): Promise<IUserComment[]> {
+    return Promise.resolve([]);
+  }
+
+  countUnreadComments(_threadId?: string): Promise<number> {
+    return Promise.resolve(0);
+  }
+
+  createCommentThread(thread: ICommentThread, firstComment: IUserComment): Promise<ICommentThread> {
+    const now = new Date().toISOString();
+    const createdThread = {
+      ...thread,
+      authorId: thread.authorId ?? firstComment.authorId,
+      authorName: thread.authorName ?? firstComment.authorName,
+      createdAt: thread.createdAt || now,
+      updatedAt: thread.updatedAt || now,
+    };
+    const createdComment = {
+      ...firstComment,
+      commentThreadId: createdThread.id,
+      createdAt: firstComment.createdAt || now,
+      updatedAt: firstComment.updatedAt || now,
+    };
+    this._commentThreads = [...this._commentThreads, createdThread];
+    this._userComments = [...this._userComments, createdComment];
+    return Promise.resolve({...createdThread});
+  }
+
+  addUserComment(threadId: string, comment: IUserComment): Promise<IUserComment> {
+    const now = new Date().toISOString();
+    const createdComment = {
+      ...comment,
+      commentThreadId: threadId,
+      createdAt: comment.createdAt || now,
+      updatedAt: comment.updatedAt || now,
+    };
+    this._userComments = [...this._userComments, createdComment];
+    this.touchCommentThread(threadId, now);
+    return Promise.resolve({...createdComment});
+  }
+
+  editUserComment(commentId: string, text: string): Promise<IUserComment> {
+    const now = new Date().toISOString();
+    const index = this._userComments.findIndex(comment => comment.id === commentId);
+    if (index === -1) throw new Error(`Comment ${commentId} not found`);
+
+    const updatedComment = {...this._userComments[index], text, updatedAt: now};
+    this._userComments = this._userComments.map((comment, i) => i === index ? updatedComment : comment);
+    this.touchCommentThread(updatedComment.commentThreadId, now);
+    return Promise.resolve({...updatedComment});
+  }
+
+  setCommentThreadStatus(threadId: string, status: ThreadStatus): Promise<ICommentThread> {
+    const now = new Date().toISOString();
+    const index = this._commentThreads.findIndex(thread => thread.id === threadId);
+    if (index === -1) throw new Error(`Comment thread ${threadId} not found`);
+
+    const updatedThread = {...this._commentThreads[index], status, updatedAt: now};
+    this._commentThreads = this._commentThreads.map((thread, i) => i === index ? updatedThread : thread);
+    return Promise.resolve({...updatedThread});
+  }
+
+  deleteUserComment(commentId: string): Promise<void> {
+    const now = new Date().toISOString();
+    this._userComments = this._userComments.map(comment => comment.id === commentId
+      ? {...comment, deletedAt: now, updatedAt: now}
+      : comment);
+    return Promise.resolve();
+  }
+
+  deleteCommentThread(threadId: string): Promise<void> {
+    const now = new Date().toISOString();
+    this._commentThreads = this._commentThreads.map(thread => thread.id === threadId
+      ? {...thread, deletedAt: now, updatedAt: now}
+      : thread);
+    this._userComments = this._userComments.map(comment => comment.commentThreadId === threadId
+      ? {...comment, deletedAt: now, updatedAt: now}
+      : comment);
+    return Promise.resolve();
+  }
+
+  markCommentRead(_commentId: string): Promise<void> {
+    return Promise.resolve();
+  }
+
+  markCommentThreadRead(_threadId: string): Promise<void> {
+    return Promise.resolve();
+  }
+
+  markAllCommentsRead(): Promise<void> {
+    return Promise.resolve();
+  }
+
+  private touchCommentThread(threadId: string, updatedAt: string): void {
+    this._commentThreads = this._commentThreads.map(thread => thread.id === threadId ? {...thread, updatedAt} : thread);
+  }
+
   private _customViews: ICustomView[] = [{
     id: 'a1b2c3d4-e5f6-7890-abcd-ef1234567890',
     name: 'Portuguese and audio',