From fe671d79fddd0b5b9f2d04b529de87025a4098c7 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Thu, 9 Jul 2026 13:49:47 +0000
Subject: [PATCH 1/6] Fix sign-in race in Playwright global setup (FE-1171)

The signin page fetches its Kratos login flow asynchronously after mount,
and submitting before the flow has loaded throws without retrying, so the
test's waitForURL never resolves.

- global-setup: wait for the /self-service/login flow response (registered
  before page.goto so it can't be missed) before clicking Submit
- signin page: disable the Submit button until the flow has loaded, so
  Playwright's actionability checks also cover this

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQLxSZtnPp3HfxFycFLwLY
---
 apps/hash-frontend/src/pages/signin.page.tsx |  3 +++
 tests/hash-playwright/global-setup.ts        | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/apps/hash-frontend/src/pages/signin.page.tsx b/apps/hash-frontend/src/pages/signin.page.tsx
index 9226bf85fab..4a59c29acce 100644
--- a/apps/hash-frontend/src/pages/signin.page.tsx
+++ b/apps/hash-frontend/src/pages/signin.page.tsx
@@ -571,6 +571,9 @@ const SigninPage: NextPageWithLayout = () => {
                       <Button
                         type="submit"
                         variant="tertiary_quiet"
+                        // The login flow is fetched asynchronously – submitting
+                        // before it has loaded cannot succeed.
+                        disabled={!flow}
                         sx={{
                           /** @todo: replace this with a blue from the design system */
                           color: "#2482FF",
diff --git a/tests/hash-playwright/global-setup.ts b/tests/hash-playwright/global-setup.ts
index 60ff553e083..9282dac452b 100644
--- a/tests/hash-playwright/global-setup.ts
+++ b/tests/hash-playwright/global-setup.ts
@@ -12,9 +12,22 @@ const signInAndSaveState = async (
   const context = await browser.newContext({ baseURL });
   const page = await context.newPage();
 
+  /**
+   * The signin page fetches a Kratos login flow asynchronously after mount
+   * (`createBrowserLoginFlow` hits `/self-service/login/browser`). Submitting
+   * before the flow has loaded throws "No sign in flow available" and no
+   * navigation ever happens. Register the wait before navigating so the
+   * response can't be missed, and await it before clicking Submit.
+   */
+  const loginFlowResponse = page.waitForResponse(
+    (response) =>
+      response.url().includes("/self-service/login") && response.ok(),
+  );
+
   await page.goto("/signin");
   await page.fill('[placeholder="Enter your email address"]', email);
   await page.fill('[type="password"]', "password");
+  await loginFlowResponse;
   await page.click("text=Submit");
   await page.waitForURL("/", { timeout: 30_000 });
 

From dddd988de8ef7b5c1ee97c850b0e7564ae071d63 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Thu, 9 Jul 2026 13:49:59 +0000
Subject: [PATCH 2/6] Allow time for type counts to load in types-page
 Playwright spec (FE-1174)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The tab counts only render once the types contexts finish loading all
types (a heavy all-versions query); until then the tabs show just their
title with a spinner. The default 5s expect timeout races that query –
give each tab-count assertion an explicit 30s timeout instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQLxSZtnPp3HfxFycFLwLY
---
 tests/hash-playwright/tests/features/types-page.spec.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tests/hash-playwright/tests/features/types-page.spec.ts b/tests/hash-playwright/tests/features/types-page.spec.ts
index d0de0b05fe3..26eec10eae5 100644
--- a/tests/hash-playwright/tests/features/types-page.spec.ts
+++ b/tests/hash-playwright/tests/features/types-page.spec.ts
@@ -20,11 +20,17 @@ test("/types page renders and loads types", async ({ page }) => {
   };
 
   /**
-   * Check that all tabs have a non-zero type count
+   * Check that all tabs have a non-zero type count.
+   *
+   * The counts render only once the types contexts have finished loading all
+   * types (a heavy all-versions query) – until then the tabs show just their
+   * title alongside a loading spinner, so allow a generous timeout rather
+   * than the default 5s.
    */
   for (const [tabTitle, href] of Object.entries(hrefByTabTitle)) {
     await expect(page.locator(`[href*="${href}"]`)).toHaveText(
       new RegExp(`^${tabTitle}[1-9]\\d*$`),
+      { timeout: 30_000 },
     );
   }
 });

From 6d1100fb12cc8dc1e999b46bde85b08eede1c579 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Thu, 9 Jul 2026 13:50:17 +0000
Subject: [PATCH 3/6] Make link target entity types honest and guard consumers
 (FE-1172)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

getOutgoingLinkAndTargetEntities / getIncomingLinkAndSourceEntities
return `undefined` for rightEntity / leftEntity when the link's
has-right-entity / has-left-entity edge is not resolved into the
subgraph, but LinkEntityAndRightEntity / LinkEntityAndLeftEntity
declared those properties as non-optional and an `as` cast hid the
mismatch. Consumers indexing `rightEntity[0]` then crash at runtime –
most visibly constructOrg, which runs via the auth context on every
page and turned a partially-consistent subgraph into an app-wide
crash loop.

- declare rightEntity / leftEntity as possibly undefined
- guard every consumer flagged by the compiler, skipping links whose
  target/source entity array is missing or empty instead of throwing
- add a changeset for @blockprotocol/graph

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQLxSZtnPp3HfxFycFLwLY
---
 .changeset/fe-1172-optional-link-targets.md   |  5 +++
 .../graphql/resolvers/knowledge/org/shared.ts |  2 +-
 .../src/components/hooks/use-account-pages.ts |  9 ++++--
 apps/hash-frontend/src/lib/user-and-org.ts    | 32 +++++++++++++------
 .../notifications-with-links-context.tsx      | 20 ++++++------
 .../linear/use-linear-integrations.ts         |  6 ++--
 .../pages/shared/block-collection-contents.ts |  2 +-
 .../block-select-data-modal.tsx               | 13 +++++---
 .../mention-view/mention-display.tsx          |  2 +-
 .../shared/mention-suggester.tsx              |  2 +-
 .../src/pages/shared/claims-table.tsx         |  4 +--
 .../links-section/incoming-links-section.tsx  |  2 +-
 .../incoming-links-table.tsx                  |  9 ++++--
 .../readonly-outgoing-links-table.tsx         |  9 ++++--
 .../outgoing-links-section/use-rows.ts        | 11 ++++---
 .../get-entity-multi-type-dependencies.ts     |  4 +--
 .../src/pages/shared/use-flow-runs-usage.ts   |  2 +-
 apps/plugin-browser/src/shared/get-user.ts    | 19 ++++++-----
 .../src/stdlib/subgraph/edge/link-entity.ts   | 14 ++++++--
 libs/@blockprotocol/graph/src/types/entity.ts | 14 ++++++--
 libs/@local/hash-isomorphic-utils/src/save.ts |  2 +-
 .../src/service-usage.ts                      |  8 ++++-
 22 files changed, 130 insertions(+), 61 deletions(-)
 create mode 100644 .changeset/fe-1172-optional-link-targets.md

diff --git a/.changeset/fe-1172-optional-link-targets.md b/.changeset/fe-1172-optional-link-targets.md
new file mode 100644
index 00000000000..dc49eb641b1
--- /dev/null
+++ b/.changeset/fe-1172-optional-link-targets.md
@@ -0,0 +1,5 @@
+---
+"@blockprotocol/graph": minor
+---
+
+Make `rightEntity` / `leftEntity` on `LinkEntityAndRightEntity` / `LinkEntityAndLeftEntity` possibly `undefined`, reflecting what `getOutgoingLinkAndTargetEntities` / `getIncomingLinkAndSourceEntities` actually return when a link's `has-right-entity` / `has-left-entity` edge is not resolved into the subgraph. Previously an unsafe cast hid this, allowing runtime crashes when consumers indexed into a missing target entity array.
diff --git a/apps/hash-api/src/graphql/resolvers/knowledge/org/shared.ts b/apps/hash-api/src/graphql/resolvers/knowledge/org/shared.ts
index e56150675e7..1e58782fea0 100644
--- a/apps/hash-api/src/graphql/resolvers/knowledge/org/shared.ts
+++ b/apps/hash-api/src/graphql/resolvers/knowledge/org/shared.ts
@@ -82,7 +82,7 @@ export const getPendingOrgInvitationsFromSubgraph = async (
       );
     }
 
-    const orgEntity = linkAndOrgEntities[0]?.leftEntity[0];
+    const orgEntity = linkAndOrgEntities[0]?.leftEntity?.[0];
 
     if (!orgEntity) {
       throw new Error(
diff --git a/apps/hash-frontend/src/components/hooks/use-account-pages.ts b/apps/hash-frontend/src/components/hooks/use-account-pages.ts
index e261cc67334..b854c467edf 100644
--- a/apps/hash-frontend/src/components/hooks/use-account-pages.ts
+++ b/apps/hash-frontend/src/components/hooks/use-account-pages.ts
@@ -71,12 +71,17 @@ export const useAccountPages = (
       );
 
       const parentLink = pageOutgoingLinks.find(({ linkEntity }) =>
-        linkEntity[0]!.metadata.entityTypeIds.includes(
+        linkEntity[0]?.metadata.entityTypeIds.includes(
           systemLinkEntityTypes.hasParent.linkEntityTypeId,
         ),
       );
 
-      const parentPage = parentLink?.rightEntity[0] ?? null;
+      /**
+       * The right entity may be missing from the subgraph (e.g. if it was
+       * not resolved when the subgraph was produced) – treat the page as
+       * having no parent in that case.
+       */
+      const parentPage = parentLink?.rightEntity?.[0] ?? null;
 
       return {
         ...simplifyProperties(latestPage.properties as PageProperties),
diff --git a/apps/hash-frontend/src/lib/user-and-org.ts b/apps/hash-frontend/src/lib/user-and-org.ts
index 79821ea0962..6d21bb3f017 100644
--- a/apps/hash-frontend/src/lib/user-and-org.ts
+++ b/apps/hash-frontend/src/lib/user-and-org.ts
@@ -194,7 +194,11 @@ export const constructOrg = (params: {
       continue;
     }
 
-    const rightEntityRevision = rightEntity[0];
+    /**
+     * The right entity may be missing from the subgraph (e.g. if it was not
+     * resolved when the subgraph was produced) – skip the link in that case.
+     */
+    const rightEntityRevision = rightEntity?.[0];
 
     if (!rightEntityRevision) {
       continue;
@@ -269,12 +273,15 @@ export const constructOrg = (params: {
       continue;
     }
 
-    const userEntityRevision = leftEntity[0];
+    /**
+     * The left entity may be missing from the subgraph (e.g. if it was not
+     * resolved when the subgraph was produced) – skip the membership in that
+     * case rather than crashing.
+     */
+    const userEntityRevision = leftEntity?.[0];
 
     if (!userEntityRevision) {
-      throw new Error(
-        `Failed to find the current user entity associated with the membership with entity ID: ${linkEntityRevision.metadata.recordId.entityId}`,
-      );
+      continue;
     }
 
     if (!isEntityUserEntity(userEntityRevision)) {
@@ -457,7 +464,7 @@ export const constructUser = (params: {
 
   for (const linkAndEntity of outgoingLinkAndTargetEntities) {
     const linkEntity = linkAndEntity.linkEntity[0];
-    const rightEntity = linkAndEntity.rightEntity[0];
+    const rightEntity = linkAndEntity.rightEntity?.[0];
 
     if (!linkEntity || !rightEntity) {
       continue;
@@ -491,7 +498,7 @@ export const constructUser = (params: {
         systemLinkEntityTypes.hasServiceAccount.linkEntityTypeId,
       )
     ) {
-      const serviceAccountEntity = linkAndEntity.rightEntity[0]!;
+      const serviceAccountEntity = rightEntity;
 
       const { profileUrl } = simplifyProperties(
         serviceAccountEntity.properties as ServiceAccount["properties"],
@@ -510,12 +517,17 @@ export const constructUser = (params: {
     }
   }
 
+  /**
+   * Non-null assertions are safe below: entries are only pushed to these
+   * arrays after checking that both `linkEntity[0]` and `rightEntity[0]`
+   * are present.
+   */
   const hasAvatar = avatarLinkAndEntities[0]
     ? {
         // these are each arrays because each entity can have multiple revisions
         linkEntity: avatarLinkAndEntities[0].linkEntity[0]!,
         imageEntity: avatarLinkAndEntities[0]
-          .rightEntity[0]! as Entity<ImageFile>,
+          .rightEntity![0]! as Entity<ImageFile>,
       }
     : undefined;
 
@@ -524,7 +536,7 @@ export const constructUser = (params: {
         // these are each arrays because each entity can have multiple revisions
         linkEntity: coverImageLinkAndEntities[0].linkEntity[0]!,
         imageEntity: coverImageLinkAndEntities[0]
-          .rightEntity[0]! as Entity<ImageFile>,
+          .rightEntity![0]! as Entity<ImageFile>,
       }
     : undefined;
 
@@ -534,7 +546,7 @@ export const constructUser = (params: {
         linkEntity: hasBioLinkAndEntities[0]
           .linkEntity[0]! as LinkEntity<HasBio>,
         profileBioEntity: hasBioLinkAndEntities[0]
-          .rightEntity[0]! as Entity<ProfileBio>,
+          .rightEntity![0]! as Entity<ProfileBio>,
       }
     : undefined;
 
diff --git a/apps/hash-frontend/src/pages/notifications.page/notifications-with-links-context.tsx b/apps/hash-frontend/src/pages/notifications.page/notifications-with-links-context.tsx
index a5c2a7899e1..e312e0f068e 100644
--- a/apps/hash-frontend/src/pages/notifications.page/notifications-with-links-context.tsx
+++ b/apps/hash-frontend/src/pages/notifications.page/notifications-with-links-context.tsx
@@ -221,25 +221,25 @@ export const useNotificationsWithLinksContextValue =
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.occurredInEntity.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             const occurredInBlock = outgoingLinks.find(
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.occurredInBlock.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             const occurredInText = outgoingLinks.find(
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.occurredInText.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             const triggeredByUserEntity = outgoingLinks.find(
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.triggeredByUser.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             if (
               !occurredInEntity ||
@@ -260,7 +260,7 @@ export const useNotificationsWithLinksContextValue =
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.occurredInComment.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             if (occurredInComment) {
               return {
@@ -297,25 +297,25 @@ export const useNotificationsWithLinksContextValue =
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.occurredInEntity.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             const occurredInBlock = outgoingLinks.find(
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.occurredInBlock.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             const triggeredByComment = outgoingLinks.find(
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.triggeredByComment.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             const triggeredByUserEntity = outgoingLinks.find(
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.triggeredByUser.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             if (
               !occurredInEntity ||
@@ -336,7 +336,7 @@ export const useNotificationsWithLinksContextValue =
               isLinkAndRightEntityWithLinkType(
                 systemLinkEntityTypes.repliedToComment.linkEntityTypeId,
               ),
-            )?.rightEntity[0];
+            )?.rightEntity?.[0];
 
             if (repliedToComment) {
               return {
diff --git a/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts b/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
index 8eef0e84a1b..330b2327a6b 100644
--- a/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
+++ b/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
@@ -120,12 +120,14 @@ export const useLinearIntegrations = (): {
               !linkEntity.metadata.archived &&
               linkEntity.metadata.entityTypeIds.includes(
                 systemLinkEntityTypes.syncLinearDataWith.linkEntityTypeId,
-              )
+              ) &&
+              // the target web may be missing from the subgraph – skip the link
+              !!linkAndTarget.rightEntity?.[0]
             );
           })
           .map((linkAndTarget) => {
             const linkEntity = linkAndTarget.linkEntity[0]!;
-            const rightEntity = linkAndTarget.rightEntity[0]!;
+            const rightEntity = linkAndTarget.rightEntity![0]!;
 
             const { linearTeamId: linearTeamIds } = simplifyProperties(
               linkEntity.properties as SyncLinearDataWithProperties,
diff --git a/apps/hash-frontend/src/pages/shared/block-collection-contents.ts b/apps/hash-frontend/src/pages/shared/block-collection-contents.ts
index 57fcb9f572b..0cb23b28ff9 100644
--- a/apps/hash-frontend/src/pages/shared/block-collection-contents.ts
+++ b/apps/hash-frontend/src/pages/shared/block-collection-contents.ts
@@ -171,7 +171,7 @@ export const getBlockCollectionContents = (params: {
           linkEntityRevisions[0].metadata.entityTypeIds.includes(
             systemLinkEntityTypes.hasData.linkEntityTypeId,
           ),
-      )?.rightEntity[0];
+      )?.rightEntity?.[0];
 
       if (!blockChildEntity) {
         throw new Error("Error fetching block data");
diff --git a/apps/hash-frontend/src/pages/shared/block-collection/block-context-menu/block-select-data-modal.tsx b/apps/hash-frontend/src/pages/shared/block-collection/block-context-menu/block-select-data-modal.tsx
index 174b23174e4..87e80eb2eb5 100644
--- a/apps/hash-frontend/src/pages/shared/block-collection/block-context-menu/block-select-data-modal.tsx
+++ b/apps/hash-frontend/src/pages/shared/block-collection/block-context-menu/block-select-data-modal.tsx
@@ -81,12 +81,15 @@ export const BlockSelectDataModal: FunctionComponent<
       blockSubgraph,
       blockDataEntity.metadata.recordId.entityId,
     )
-      .filter(({ linkEntity: linkEntityRevisions }) =>
-        linkEntityRevisions[0]?.metadata.entityTypeIds.includes(
-          blockProtocolLinkEntityTypes.hasQuery.linkEntityTypeId,
-        ),
+      .filter(
+        ({ linkEntity: linkEntityRevisions, rightEntity }) =>
+          linkEntityRevisions[0]?.metadata.entityTypeIds.includes(
+            blockProtocolLinkEntityTypes.hasQuery.linkEntityTypeId,
+          ) &&
+          // the target entity may be missing from the subgraph – skip the link
+          !!rightEntity?.[0],
       )
-      .map(({ rightEntity }) => rightEntity[0] as HashEntity<Query>);
+      .map(({ rightEntity }) => rightEntity![0] as HashEntity<Query>);
 
     return existingQueries[0];
   }, [blockSubgraph, blockDataEntity]);
diff --git a/apps/hash-frontend/src/pages/shared/block-collection/mention-view/mention-display.tsx b/apps/hash-frontend/src/pages/shared/block-collection/mention-view/mention-display.tsx
index fc1c4a9f367..0c83aba73e0 100644
--- a/apps/hash-frontend/src/pages/shared/block-collection/mention-view/mention-display.tsx
+++ b/apps/hash-frontend/src/pages/shared/block-collection/mention-view/mention-display.tsx
@@ -139,7 +139,7 @@ export const MentionDisplay: FunctionComponent<MentionDisplayProps> = ({
           ),
       );
 
-      const targetEntity = outgoingLinkAndTargetEntities?.rightEntity[0];
+      const targetEntity = outgoingLinkAndTargetEntities?.rightEntity?.[0];
 
       const targetEntityLabel = targetEntity
         ? generateEntityLabel(entitySubgraph, targetEntity)
diff --git a/apps/hash-frontend/src/pages/shared/block-collection/shared/mention-suggester.tsx b/apps/hash-frontend/src/pages/shared/block-collection/shared/mention-suggester.tsx
index 508eca2dd6e..bfe23603db9 100644
--- a/apps/hash-frontend/src/pages/shared/block-collection/shared/mention-suggester.tsx
+++ b/apps/hash-frontend/src/pages/shared/block-collection/shared/mention-suggester.tsx
@@ -398,7 +398,7 @@ export const MentionSuggester: FunctionComponent<MentionSuggesterProps> = ({
         ).map<Extract<SubMenuItem, { kind: "outgoing-link" }>>(
           ({
             linkEntity: linkEntityRevisions,
-            rightEntity: rightEntityRevisions,
+            rightEntity: rightEntityRevisions = [],
           }) => {
             const [linkEntity] = linkEntityRevisions;
             const [rightEntity] = rightEntityRevisions;
diff --git a/apps/hash-frontend/src/pages/shared/claims-table.tsx b/apps/hash-frontend/src/pages/shared/claims-table.tsx
index 720f3db3581..c389d81697c 100644
--- a/apps/hash-frontend/src/pages/shared/claims-table.tsx
+++ b/apps/hash-frontend/src/pages/shared/claims-table.tsx
@@ -429,13 +429,13 @@ export const ClaimsTable = memo(
               systemLinkEntityTypes.hasObject.linkEntityTypeId,
             )
           ) {
-            objectEntityId = rightEntity[0]?.entityId;
+            objectEntityId = rightEntity?.[0]?.entityId;
           } else if (
             linkEntity[0]?.metadata.entityTypeIds.includes(
               systemLinkEntityTypes.hasSubject.linkEntityTypeId,
             )
           ) {
-            subjectEntityId = rightEntity[0]?.entityId;
+            subjectEntityId = rightEntity?.[0]?.entityId;
           }
         }
 
diff --git a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section.tsx b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section.tsx
index 4bbcbfacd02..03a3896a135 100644
--- a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section.tsx
+++ b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section.tsx
@@ -140,7 +140,7 @@ export const IncomingLinksSection = ({
         !draftLinksToArchive.includes(
           incomingLinkAndSource.linkEntity[0].entityId,
         ) &&
-        incomingLinkAndSource.leftEntity[0] &&
+        incomingLinkAndSource.leftEntity?.[0] &&
         !incomingLinkAndSource.leftEntity[0].metadata.entityTypeIds.includes(
           systemEntityTypes.claim.entityTypeId,
         )
diff --git a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section/incoming-links-table.tsx b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section/incoming-links-table.tsx
index cc3096f117e..785c63216b9 100644
--- a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section/incoming-links-table.tsx
+++ b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/incoming-links-section/incoming-links-table.tsx
@@ -362,9 +362,14 @@ export const IncomingLinksTable = memo(
           linkEntityTypeIds.add(linkType.$id);
         }
 
-        const leftEntity = leftEntityRevisions[0];
+        const leftEntity = leftEntityRevisions?.[0];
         if (!leftEntity) {
-          throw new Error("Expected at least one left entity revision");
+          /**
+           * The source entity may be missing from the subgraph (e.g. if it
+           * was not resolved when the subgraph was produced) – skip the link
+           * rather than crashing.
+           */
+          continue;
         }
 
         const leftEntityClosedMultiType = getClosedMultiEntityTypeFromMap(
diff --git a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/readonly-outgoing-links-table.tsx b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/readonly-outgoing-links-table.tsx
index 336903f8b02..cbd6924c2e2 100644
--- a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/readonly-outgoing-links-table.tsx
+++ b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/readonly-outgoing-links-table.tsx
@@ -341,9 +341,14 @@ export const OutgoingLinksTable = memo(
           linkEntityTypeIds.add(linkType.$id);
         }
 
-        const rightEntity = rightEntityRevisions[0];
+        const rightEntity = rightEntityRevisions?.[0];
         if (!rightEntity) {
-          throw new Error("Expected at least one right entity revision");
+          /**
+           * The target entity may be missing from the subgraph (e.g. if it
+           * was not resolved when the subgraph was produced) – skip the link
+           * rather than crashing.
+           */
+          continue;
         }
 
         const rightEntityClosedMultiType = getClosedMultiEntityTypeFromMap(
diff --git a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/use-rows.ts b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/use-rows.ts
index 11c69d00872..caa2ed268ad 100644
--- a/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/use-rows.ts
+++ b/apps/hash-frontend/src/pages/shared/entity/entity-editor/links-section/outgoing-links-section/use-rows.ts
@@ -145,7 +145,7 @@ export const useRows = ({
             );
           }
 
-          const targetEntityRevisions = [...entities.rightEntity];
+          const targetEntityRevisions = [...(entities.rightEntity ?? [])];
           targetEntityRevisions.sort((entityA, entityB) =>
             intervalCompareWithInterval(
               entityA.metadata.temporalVersioning[variableAxis],
@@ -156,9 +156,12 @@ export const useRows = ({
           const latestTargetEntityRevision = targetEntityRevisions.at(-1);
 
           if (!latestTargetEntityRevision) {
-            throw new Error(
-              `Couldn't find a target link entity revision from ${entity.metadata.recordId.entityId}, this is likely an implementation bug in the stdlib`,
-            );
+            /**
+             * The target entity may be missing from the subgraph (e.g. if it
+             * was not resolved when the subgraph was produced) – skip the
+             * link rather than crashing.
+             */
+            continue;
           }
 
           const { entityTypeIds, recordId } = latestLinkEntityRevision.metadata;
diff --git a/apps/hash-frontend/src/pages/shared/entity/get-entity-multi-type-dependencies.ts b/apps/hash-frontend/src/pages/shared/entity/get-entity-multi-type-dependencies.ts
index 797dedcf686..7c444bba1a7 100644
--- a/apps/hash-frontend/src/pages/shared/entity/get-entity-multi-type-dependencies.ts
+++ b/apps/hash-frontend/src/pages/shared/entity/get-entity-multi-type-dependencies.ts
@@ -83,7 +83,7 @@ export const getEntityMultiTypeDependencies = ({
       console.warn(`Link entity not found in subgraph`);
     }
 
-    const rightEntityRevision = rightEntity[0];
+    const rightEntityRevision = rightEntity?.[0];
 
     if (rightEntityRevision) {
       addEntityTypeIdsToSet(
@@ -110,7 +110,7 @@ export const getEntityMultiTypeDependencies = ({
       console.warn(`Link entity not found in subgraph`);
     }
 
-    const leftEntityRevision = leftEntity[0];
+    const leftEntityRevision = leftEntity?.[0];
 
     if (leftEntityRevision) {
       addEntityTypeIdsToSet(uniqueJoinedMultiEntityTypeIds, leftEntityRevision);
diff --git a/apps/hash-frontend/src/pages/shared/use-flow-runs-usage.ts b/apps/hash-frontend/src/pages/shared/use-flow-runs-usage.ts
index 57f13dd4818..864172aaea3 100644
--- a/apps/hash-frontend/src/pages/shared/use-flow-runs-usage.ts
+++ b/apps/hash-frontend/src/pages/shared/use-flow-runs-usage.ts
@@ -131,7 +131,7 @@ export const useFlowRunsUsage = ({
           );
         }
 
-        const incurredInEntity = incurredInLinkAndEntities[0]!.rightEntity[0];
+        const incurredInEntity = incurredInLinkAndEntities[0]!.rightEntity?.[0];
 
         if (!incurredInEntity) {
           return false;
diff --git a/apps/plugin-browser/src/shared/get-user.ts b/apps/plugin-browser/src/shared/get-user.ts
index 7adfa3e04fe..febf53e66d2 100644
--- a/apps/plugin-browser/src/shared/get-user.ts
+++ b/apps/plugin-browser/src/shared/get-user.ts
@@ -44,7 +44,7 @@ const getAvatarForEntity = (
       systemLinkEntityTypes.hasAvatar.linkEntityTypeId,
     ),
   );
-  return avatarLinkAndEntities[0]?.rightEntity[0] as
+  return avatarLinkAndEntities[0]?.rightEntity?.[0] as
     | Entity<ImageFile>
     | undefined;
 };
@@ -88,10 +88,13 @@ export const getUser = (): Promise<LocalStorage["user"] | null> => {
       const orgLinksAndEntities = getOutgoingLinkAndTargetEntities(
         subgraph,
         user.metadata.recordId.entityId,
-      ).filter(({ linkEntity }) =>
-        linkEntity[0]?.metadata.entityTypeIds.includes(
-          systemLinkEntityTypes.isMemberOf.linkEntityTypeId,
-        ),
+      ).filter(
+        ({ linkEntity, rightEntity }) =>
+          linkEntity[0]?.metadata.entityTypeIds.includes(
+            systemLinkEntityTypes.isMemberOf.linkEntityTypeId,
+          ) &&
+          // the org entity may be missing from the subgraph – skip the link
+          !!rightEntity?.[0],
       );
 
       const userBrowserPreferences = getOutgoingLinkAndTargetEntities(
@@ -102,10 +105,10 @@ export const getUser = (): Promise<LocalStorage["user"] | null> => {
           linkEntity[0]?.metadata.entityTypeIds.includes(
             systemLinkEntityTypes.has.linkEntityTypeId,
           ) &&
-          rightEntity[0]?.metadata.entityTypeIds.includes(
+          rightEntity?.[0]?.metadata.entityTypeIds.includes(
             systemEntityTypes.browserPluginSettings.entityTypeId,
           ),
-      )[0]?.rightEntity[0];
+      )[0]?.rightEntity?.[0];
 
       let settingsEntityId: EntityId;
 
@@ -224,7 +227,7 @@ export const getUser = (): Promise<LocalStorage["user"] | null> => {
       }
 
       const orgs = orgLinksAndEntities.map(({ rightEntity }) => {
-        const org = rightEntity[0]!;
+        const org = rightEntity![0]!;
         const orgAvatar = getAvatarForEntity(
           subgraph,
           org.metadata.recordId.entityId,
diff --git a/libs/@blockprotocol/graph/src/stdlib/subgraph/edge/link-entity.ts b/libs/@blockprotocol/graph/src/stdlib/subgraph/edge/link-entity.ts
index 8fccf6fc359..e442790124f 100644
--- a/libs/@blockprotocol/graph/src/stdlib/subgraph/edge/link-entity.ts
+++ b/libs/@blockprotocol/graph/src/stdlib/subgraph/edge/link-entity.ts
@@ -330,6 +330,8 @@ export const getOutgoingLinkAndTargetEntities = <
     ([linkEntityId, linkEntityRevisions]) => {
       return {
         linkEntity: linkEntityRevisions,
+        // `undefined` if the link's `has-right-entity` edge is not resolved
+        // into the subgraph
         rightEntity: getRightEntityForLinkEntity(
           subgraph,
           linkEntityId,
@@ -337,7 +339,10 @@ export const getOutgoingLinkAndTargetEntities = <
         ),
       };
     },
-  ) as LinkAndRightEntities; // @todo consider fixing generics in functions called within
+    // The cast is only needed for the caller-provided generic – the mapped
+    // value is a valid `LinkEntityAndRightEntity[]`.
+    // @todo consider fixing generics in functions called within
+  ) as LinkAndRightEntities;
 };
 
 /**
@@ -386,6 +391,8 @@ export const getIncomingLinkAndSourceEntities = <
     ([linkEntityId, linkEntityRevisions]) => {
       return {
         linkEntity: linkEntityRevisions,
+        // `undefined` if the link's `has-left-entity` edge is not resolved
+        // into the subgraph
         leftEntity: getLeftEntityForLinkEntity(
           subgraph,
           linkEntityId,
@@ -393,5 +400,8 @@ export const getIncomingLinkAndSourceEntities = <
         ),
       };
     },
-  ) as LinkAndLeftEntities; // @todo consider fixing generics in functions called within
+    // The cast is only needed for the caller-provided generic – the mapped
+    // value is a valid `LinkEntityAndLeftEntity[]`.
+    // @todo consider fixing generics in functions called within
+  ) as LinkAndLeftEntities;
 };
diff --git a/libs/@blockprotocol/graph/src/types/entity.ts b/libs/@blockprotocol/graph/src/types/entity.ts
index 4c0344b22e7..96ab6b52848 100644
--- a/libs/@blockprotocol/graph/src/types/entity.ts
+++ b/libs/@blockprotocol/graph/src/types/entity.ts
@@ -36,7 +36,12 @@ export type LinkEntityAndRightEntity<
   LinkEntityImpl extends LinkEntity = LinkEntity,
 > = {
   linkEntity: LinkEntityImpl[];
-  rightEntity: EntityImpl[];
+  /**
+   * The revisions of the link's target entity, or `undefined` if the link's
+   * `has-right-entity` edge was not resolved into the subgraph (e.g. because
+   * of resolve depths, or because the subgraph is only partially consistent).
+   */
+  rightEntity?: EntityImpl[];
 };
 
 export type LinkEntityAndLeftEntity<
@@ -44,7 +49,12 @@ export type LinkEntityAndLeftEntity<
   LinkEntityImpl extends LinkEntity = LinkEntity,
 > = {
   linkEntity: LinkEntityImpl[];
-  leftEntity: EntityImpl[];
+  /**
+   * The revisions of the link's source entity, or `undefined` if the link's
+   * `has-left-entity` edge was not resolved into the subgraph (e.g. because
+   * of resolve depths, or because the subgraph is only partially consistent).
+   */
+  leftEntity?: EntityImpl[];
 };
 
 export type CreateEntityData = {
diff --git a/libs/@local/hash-isomorphic-utils/src/save.ts b/libs/@local/hash-isomorphic-utils/src/save.ts
index f1df878df69..817d39cae58 100644
--- a/libs/@local/hash-isomorphic-utils/src/save.ts
+++ b/libs/@local/hash-isomorphic-utils/src/save.ts
@@ -463,7 +463,7 @@ const mapEntityToGqlBlock = (
       linkEntityRevisions[0].metadata.entityTypeIds.includes(
         systemLinkEntityTypes.hasData.linkEntityTypeId,
       ),
-  )?.rightEntity[0];
+  )?.rightEntity?.[0];
 
   if (!blockChildEntity) {
     throw new Error(
diff --git a/libs/@local/hash-isomorphic-utils/src/service-usage.ts b/libs/@local/hash-isomorphic-utils/src/service-usage.ts
index 785c39b7e01..be23f03d6a1 100644
--- a/libs/@local/hash-isomorphic-utils/src/service-usage.ts
+++ b/libs/@local/hash-isomorphic-utils/src/service-usage.ts
@@ -48,7 +48,13 @@ const getServiceFeatureForUsage = ({
   }
 
   const serviceFeatureEntity = serviceFeatureLinkAndEntities[0]!
-    .rightEntity[0]! as HashEntity<ServiceFeature>;
+    .rightEntity?.[0] as HashEntity<ServiceFeature> | undefined;
+
+  if (!serviceFeatureEntity) {
+    throw new Error(
+      `Service feature entity missing from subgraph for service usage record ${usageRecord.metadata.recordId.entityId}.`,
+    );
+  }
 
   const { featureName, serviceName, serviceUnitCost } = simplifyProperties(
     serviceFeatureEntity.properties,

From fc64a12970775a5afb8a5fd711555c1b39d13448 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 10 Jul 2026 10:50:25 +0000
Subject: [PATCH 4/6] Throw invariant errors instead of silently skipping
 missing public entities (FE-1172)

Where a link's target is a public entity whose presence in the subgraph
is guaranteed by the query (user/org membership targets, parent pages,
linear-sync web targets), a missing entity now throws a descriptive
error referencing BE-644 instead of being silently skipped. The root
cause (subgraph reads not being snapshot-consistent) is being fixed
server-side; these errors keep the invariant violation loud if it ever
recurs. Genuinely-optional absences (notifications, mentions, links
tables, permission-filterable targets) remain graceful.
---
 .../src/components/hooks/use-account-pages.ts | 20 +++++++++-----
 apps/hash-frontend/src/lib/user-and-org.ts    | 16 +++++++-----
 .../linear/use-linear-integrations.ts         | 19 +++++++++++---
 apps/plugin-browser/src/shared/get-user.ts    | 26 ++++++++++++-------
 4 files changed, 56 insertions(+), 25 deletions(-)

diff --git a/apps/hash-frontend/src/components/hooks/use-account-pages.ts b/apps/hash-frontend/src/components/hooks/use-account-pages.ts
index b854c467edf..19ea4672624 100644
--- a/apps/hash-frontend/src/components/hooks/use-account-pages.ts
+++ b/apps/hash-frontend/src/components/hooks/use-account-pages.ts
@@ -76,12 +76,20 @@ export const useAccountPages = (
         ),
       );
 
-      /**
-       * The right entity may be missing from the subgraph (e.g. if it was
-       * not resolved when the subgraph was produced) – treat the page as
-       * having no parent in that case.
-       */
-      const parentPage = parentLink?.rightEntity?.[0] ?? null;
+      const parentPage = parentLink ? parentLink.rightEntity?.[0] : null;
+
+      if (parentLink && !parentPage) {
+        /**
+         * The query resolves one level of outgoing `has-parent` links, so if
+         * the link is in the subgraph its target page must be too. A missing
+         * parent page means the subgraph is internally inconsistent (e.g.
+         * produced by non snapshot-consistent reads – see BE-644), which we
+         * surface loudly rather than silently treating the page as parentless.
+         */
+        throw new Error(
+          `Invariant violation: has-parent link ${parentLink.linkEntity[0]?.metadata.recordId.entityId} on page ${latestPage.metadata.recordId.entityId} is missing its right (parent page) entity in the subgraph – see BE-644`,
+        );
+      }
 
       return {
         ...simplifyProperties(latestPage.properties as PageProperties),
diff --git a/apps/hash-frontend/src/lib/user-and-org.ts b/apps/hash-frontend/src/lib/user-and-org.ts
index 6d21bb3f017..acba33966ce 100644
--- a/apps/hash-frontend/src/lib/user-and-org.ts
+++ b/apps/hash-frontend/src/lib/user-and-org.ts
@@ -273,15 +273,19 @@ export const constructOrg = (params: {
       continue;
     }
 
-    /**
-     * The left entity may be missing from the subgraph (e.g. if it was not
-     * resolved when the subgraph was produced) – skip the membership in that
-     * case rather than crashing.
-     */
     const userEntityRevision = leftEntity?.[0];
 
     if (!userEntityRevision) {
-      continue;
+      /**
+       * User entities are public – if the membership link is in the subgraph,
+       * its left (user) entity must be too. A missing user entity means the
+       * subgraph is internally inconsistent (e.g. produced by non
+       * snapshot-consistent reads – see BE-644), which we surface loudly
+       * rather than silently dropping the membership.
+       */
+      throw new Error(
+        `Invariant violation: membership link ${linkEntityRevision.metadata.recordId.entityId} is missing its left (user) entity in the subgraph – see BE-644`,
+      );
     }
 
     if (!isEntityUserEntity(userEntityRevision)) {
diff --git a/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts b/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
index 330b2327a6b..96d75f0e50c 100644
--- a/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
+++ b/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
@@ -120,14 +120,25 @@ export const useLinearIntegrations = (): {
               !linkEntity.metadata.archived &&
               linkEntity.metadata.entityTypeIds.includes(
                 systemLinkEntityTypes.syncLinearDataWith.linkEntityTypeId,
-              ) &&
-              // the target web may be missing from the subgraph – skip the link
-              !!linkAndTarget.rightEntity?.[0]
+              )
             );
           })
           .map((linkAndTarget) => {
             const linkEntity = linkAndTarget.linkEntity[0]!;
-            const rightEntity = linkAndTarget.rightEntity![0]!;
+            const rightEntity = linkAndTarget.rightEntity?.[0];
+
+            if (!rightEntity) {
+              /**
+               * The target of a `syncLinearDataWith` link is a user or org
+               * (web) entity, which is public – if the link is in the
+               * subgraph its target must be too. A missing target means the
+               * subgraph is internally inconsistent (e.g. produced by non
+               * snapshot-consistent reads – see BE-644).
+               */
+              throw new Error(
+                `Invariant violation: syncLinearDataWith link ${linkEntity.metadata.recordId.entityId} is missing its right (web) entity in the subgraph – see BE-644`,
+              );
+            }
 
             const { linearTeamId: linearTeamIds } = simplifyProperties(
               linkEntity.properties as SyncLinearDataWithProperties,
diff --git a/apps/plugin-browser/src/shared/get-user.ts b/apps/plugin-browser/src/shared/get-user.ts
index febf53e66d2..2177537ee2f 100644
--- a/apps/plugin-browser/src/shared/get-user.ts
+++ b/apps/plugin-browser/src/shared/get-user.ts
@@ -88,13 +88,10 @@ export const getUser = (): Promise<LocalStorage["user"] | null> => {
       const orgLinksAndEntities = getOutgoingLinkAndTargetEntities(
         subgraph,
         user.metadata.recordId.entityId,
-      ).filter(
-        ({ linkEntity, rightEntity }) =>
-          linkEntity[0]?.metadata.entityTypeIds.includes(
-            systemLinkEntityTypes.isMemberOf.linkEntityTypeId,
-          ) &&
-          // the org entity may be missing from the subgraph – skip the link
-          !!rightEntity?.[0],
+      ).filter(({ linkEntity }) =>
+        linkEntity[0]?.metadata.entityTypeIds.includes(
+          systemLinkEntityTypes.isMemberOf.linkEntityTypeId,
+        ),
       );
 
       const userBrowserPreferences = getOutgoingLinkAndTargetEntities(
@@ -226,8 +223,19 @@ export const getUser = (): Promise<LocalStorage["user"] | null> => {
         });
       }
 
-      const orgs = orgLinksAndEntities.map(({ rightEntity }) => {
-        const org = rightEntity![0]!;
+      const orgs = orgLinksAndEntities.map(({ linkEntity, rightEntity }) => {
+        const org = rightEntity?.[0];
+        if (!org) {
+          /**
+           * Org entities are public – if the membership link is in the
+           * subgraph, its right (org) entity must be too. A missing org
+           * entity means the subgraph is internally inconsistent (e.g.
+           * produced by non snapshot-consistent reads – see BE-644).
+           */
+          throw new Error(
+            `Invariant violation: membership link ${linkEntity[0]?.metadata.recordId.entityId} is missing its right (org) entity in the subgraph – see BE-644`,
+          );
+        }
         const orgAvatar = getAvatarForEntity(
           subgraph,
           org.metadata.recordId.entityId,

From 192c5d3c26ce1e12e80db883a481ed19730f8350 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 10 Jul 2026 10:50:36 +0000
Subject: [PATCH 5/6] Speed up /types page counts with a latest-only query
 instead of raising test timeout (FE-1174)

The /types page previously derived its entity type tab counts from the
entity types context, which fetches every version of every entity type
(including archived ones) with deep constraint resolution - a heavy
query that could take longer than the Playwright default expect timeout
to resolve. The page now runs its own latestOnly query with constraint
resolve depths zeroed (only the inheritance chain is needed to classify
link types), and classifies link vs non-link types locally.

The 30s expect timeout previously added to the types-page spec is
reverted: the default 5s timeout is the page's load budget.
---
 .../src/pages/types/[[...type-kind]].page.tsx | 99 +++++++++++++------
 .../tests/features/types-page.spec.ts         | 10 +-
 2 files changed, 72 insertions(+), 37 deletions(-)

diff --git a/apps/hash-frontend/src/pages/types/[[...type-kind]].page.tsx b/apps/hash-frontend/src/pages/types/[[...type-kind]].page.tsx
index dfdf28736cb..22ada4efe3c 100644
--- a/apps/hash-frontend/src/pages/types/[[...type-kind]].page.tsx
+++ b/apps/hash-frontend/src/pages/types/[[...type-kind]].page.tsx
@@ -2,11 +2,11 @@ import { Box, Container, Stack, Typography } from "@mui/material";
 import { NextSeo } from "next-seo";
 import { useCallback, useEffect, useMemo, useState } from "react";
 
-import { getRoots } from "@blockprotocol/graph/stdlib";
+import { getEntityTypes, getRoots } from "@blockprotocol/graph/stdlib";
 
 import { useBlockProtocolQueryDataTypes } from "../../components/hooks/block-protocol-functions/ontology/use-block-protocol-query-data-types";
-import { useLatestEntityTypesOptional } from "../../shared/entity-types-context/hooks";
-import { useEntityTypesContextRequired } from "../../shared/entity-types-context/hooks/use-entity-types-context-required";
+import { useBlockProtocolQueryEntityTypes } from "../../components/hooks/block-protocol-functions/ontology/use-block-protocol-query-entity-types";
+import { isSpecialEntityType } from "../../shared/entity-types-context/shared/is-special-entity-type";
 import { FilesLightIcon } from "../../shared/icons/files-light-icon";
 import { PlusRegularIcon } from "../../shared/icons/plus-regular";
 import { getLayoutWithSidebar } from "../../shared/layout";
@@ -22,7 +22,10 @@ import {
 
 import type { NextPageWithLayout } from "../../shared/layout";
 import type { DataTypeRootType } from "@blockprotocol/graph";
-import type { DataTypeWithMetadata } from "@blockprotocol/type-system";
+import type {
+  DataTypeWithMetadata,
+  EntityTypeWithMetadata,
+} from "@blockprotocol/type-system";
 import type { GetServerSideProps } from "next";
 
 type ParsedQueryKindParam =
@@ -52,33 +55,73 @@ export const getServerSideProps: GetServerSideProps<
 };
 
 const TypesPage: NextPageWithLayout<TypesPageProps> = ({ currentTab }) => {
-  const { latestEntityTypes } = useLatestEntityTypesOptional({
-    includeArchived: true,
-  });
+  const { queryEntityTypes } = useBlockProtocolQueryEntityTypes();
 
-  const { isSpecialEntityTypeLookup } = useEntityTypesContextRequired();
+  const [latestEntityTypesByKind, setLatestEntityTypesByKind] = useState<{
+    nonLink: EntityTypeWithMetadata[];
+    link: EntityTypeWithMetadata[];
+  }>();
 
-  const latestNonLinkEntityTypes = useMemo(
-    () =>
-      isSpecialEntityTypeLookup
-        ? latestEntityTypes?.filter(
-            (entityType) =>
-              !isSpecialEntityTypeLookup[entityType.schema.$id]?.isLink,
-          )
-        : undefined,
-    [isSpecialEntityTypeLookup, latestEntityTypes],
-  );
+  /**
+   * This page only lists the latest version of each entity type, so it runs
+   * its own `latestOnly` query rather than waiting on the entity types
+   * context, which fetches all versions of all entity types (including
+   * archived ones) – a much heavier query.
+   *
+   * Constraint resolve depths are zeroed because only the inheritance chain
+   * (`inheritsFrom`, kept at its default depth) is needed to decide whether a
+   * type is a link type.
+   */
+  const fetchEntityTypes = useCallback(async () => {
+    const { data: subgraph } = await queryEntityTypes({
+      data: {
+        latestOnly: true,
+        includeArchived: true,
+        graphResolveDepths: {
+          constrainsValuesOn: 0,
+          constrainsPropertiesOn: 0,
+          constrainsLinksOn: 0,
+          constrainsLinkDestinationsOn: 0,
+        },
+      },
+    });
 
-  const latestLinkEntityTypes = useMemo(
-    () =>
-      isSpecialEntityTypeLookup
-        ? latestEntityTypes?.filter(
-            (entityType) =>
-              isSpecialEntityTypeLookup[entityType.schema.$id]?.isLink,
-          )
-        : undefined,
-    [isSpecialEntityTypeLookup, latestEntityTypes],
-  );
+    if (!subgraph) {
+      return;
+    }
+
+    const latestEntityTypes = getRoots(subgraph);
+
+    /**
+     * All (transitive) parents of the latest entity types are resolved into
+     * the subgraph via its `inheritsFrom` depth, so the lookup by versioned
+     * URL contains everything `isSpecialEntityType` needs to walk each
+     * type's inheritance chain.
+     */
+    const typesByVersion = Object.fromEntries(
+      getEntityTypes(subgraph).map((type) => [type.schema.$id, type]),
+    );
+
+    const nonLink: EntityTypeWithMetadata[] = [];
+    const link: EntityTypeWithMetadata[] = [];
+
+    for (const entityType of latestEntityTypes) {
+      if (isSpecialEntityType(entityType.schema, typesByVersion).isLink) {
+        link.push(entityType);
+      } else {
+        nonLink.push(entityType);
+      }
+    }
+
+    setLatestEntityTypesByKind({ nonLink, link });
+  }, [queryEntityTypes]);
+
+  useEffect(() => {
+    void fetchEntityTypes();
+  }, [fetchEntityTypes]);
+
+  const latestNonLinkEntityTypes = latestEntityTypesByKind?.nonLink;
+  const latestLinkEntityTypes = latestEntityTypesByKind?.link;
 
   const { queryDataTypes } = useBlockProtocolQueryDataTypes();
 
diff --git a/tests/hash-playwright/tests/features/types-page.spec.ts b/tests/hash-playwright/tests/features/types-page.spec.ts
index 26eec10eae5..050d7beb980 100644
--- a/tests/hash-playwright/tests/features/types-page.spec.ts
+++ b/tests/hash-playwright/tests/features/types-page.spec.ts
@@ -19,18 +19,10 @@ test("/types page renders and loads types", async ({ page }) => {
     "Data Types": `${pathPrefix}data-type`,
   };
 
-  /**
-   * Check that all tabs have a non-zero type count.
-   *
-   * The counts render only once the types contexts have finished loading all
-   * types (a heavy all-versions query) – until then the tabs show just their
-   * title alongside a loading spinner, so allow a generous timeout rather
-   * than the default 5s.
-   */
+  // Check that all tabs have a non-zero type count
   for (const [tabTitle, href] of Object.entries(hrefByTabTitle)) {
     await expect(page.locator(`[href*="${href}"]`)).toHaveText(
       new RegExp(`^${tabTitle}[1-9]\\d*$`),
-      { timeout: 30_000 },
     );
   }
 });

From cda0c3413f2d83f730ac58e71fef4a9ab1bb6eba Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Fri, 10 Jul 2026 11:13:14 +0000
Subject: [PATCH 6/6] Address review: timeless error messages and bind checked
 entities to variables

Remove ticket references from invariant-error messages and comments -
the errors describe what is wrong, not which ticket tracks it. In
constructUser, collect the checked link/target entity revisions instead
of re-indexing the revision arrays with non-null assertions afterwards.
---
 .../src/components/hooks/use-account-pages.ts |  5 +-
 apps/hash-frontend/src/lib/user-and-org.ts    | 58 +++++++++----------
 .../linear/use-linear-integrations.ts         |  5 +-
 apps/plugin-browser/src/shared/get-user.ts    |  5 +-
 4 files changed, 33 insertions(+), 40 deletions(-)

diff --git a/apps/hash-frontend/src/components/hooks/use-account-pages.ts b/apps/hash-frontend/src/components/hooks/use-account-pages.ts
index 19ea4672624..2757b5b7b09 100644
--- a/apps/hash-frontend/src/components/hooks/use-account-pages.ts
+++ b/apps/hash-frontend/src/components/hooks/use-account-pages.ts
@@ -82,12 +82,11 @@ export const useAccountPages = (
         /**
          * The query resolves one level of outgoing `has-parent` links, so if
          * the link is in the subgraph its target page must be too. A missing
-         * parent page means the subgraph is internally inconsistent (e.g.
-         * produced by non snapshot-consistent reads – see BE-644), which we
+         * parent page means the subgraph is internally inconsistent, which we
          * surface loudly rather than silently treating the page as parentless.
          */
         throw new Error(
-          `Invariant violation: has-parent link ${parentLink.linkEntity[0]?.metadata.recordId.entityId} on page ${latestPage.metadata.recordId.entityId} is missing its right (parent page) entity in the subgraph – see BE-644`,
+          `Invariant violation: has-parent link ${parentLink.linkEntity[0]?.metadata.recordId.entityId} on page ${latestPage.metadata.recordId.entityId} is missing its right (parent page) entity in the subgraph`,
         );
       }
 
diff --git a/apps/hash-frontend/src/lib/user-and-org.ts b/apps/hash-frontend/src/lib/user-and-org.ts
index acba33966ce..7107fac6380 100644
--- a/apps/hash-frontend/src/lib/user-and-org.ts
+++ b/apps/hash-frontend/src/lib/user-and-org.ts
@@ -279,12 +279,11 @@ export const constructOrg = (params: {
       /**
        * User entities are public – if the membership link is in the subgraph,
        * its left (user) entity must be too. A missing user entity means the
-       * subgraph is internally inconsistent (e.g. produced by non
-       * snapshot-consistent reads – see BE-644), which we surface loudly
-       * rather than silently dropping the membership.
+       * subgraph is internally inconsistent, which we surface loudly rather
+       * than silently dropping the membership.
        */
       throw new Error(
-        `Invariant violation: membership link ${linkEntityRevision.metadata.recordId.entityId} is missing its left (user) entity in the subgraph – see BE-644`,
+        `Invariant violation: membership link ${linkEntityRevision.metadata.recordId.entityId} is missing its left (user) entity in the subgraph`,
       );
     }
 
@@ -461,9 +460,15 @@ export const constructUser = (params: {
     intervalForTimestamp(currentTimestamp()),
   );
 
-  const avatarLinkAndEntities: LinkEntityAndRightEntity[] = [];
-  const coverImageLinkAndEntities: LinkEntityAndRightEntity[] = [];
-  const hasBioLinkAndEntities: LinkEntityAndRightEntity[] = [];
+  /**
+   * These hold the latest revision of each link and its target entity, taken
+   * from the revision arrays after checking that both are present.
+   */
+  type LinkAndTargetRevision = { linkEntity: LinkEntity; rightEntity: Entity };
+
+  const avatarLinkAndEntities: LinkAndTargetRevision[] = [];
+  const coverImageLinkAndEntities: LinkAndTargetRevision[] = [];
+  const hasBioLinkAndEntities: LinkAndTargetRevision[] = [];
   const hasServiceAccounts: User["hasServiceAccounts"] = [];
 
   for (const linkAndEntity of outgoingLinkAndTargetEntities) {
@@ -479,7 +484,7 @@ export const constructUser = (params: {
     if (
       entityTypeIds.includes(systemLinkEntityTypes.hasAvatar.linkEntityTypeId)
     ) {
-      avatarLinkAndEntities.push(linkAndEntity);
+      avatarLinkAndEntities.push({ linkEntity, rightEntity });
       continue;
     }
 
@@ -488,12 +493,12 @@ export const constructUser = (params: {
         systemLinkEntityTypes.hasCoverImage.linkEntityTypeId,
       )
     ) {
-      coverImageLinkAndEntities.push(linkAndEntity);
+      coverImageLinkAndEntities.push({ linkEntity, rightEntity });
       continue;
     }
 
     if (entityTypeIds.includes(systemLinkEntityTypes.hasBio.linkEntityTypeId)) {
-      hasBioLinkAndEntities.push(linkAndEntity);
+      hasBioLinkAndEntities.push({ linkEntity, rightEntity });
       continue;
     }
 
@@ -521,36 +526,27 @@ export const constructUser = (params: {
     }
   }
 
-  /**
-   * Non-null assertions are safe below: entries are only pushed to these
-   * arrays after checking that both `linkEntity[0]` and `rightEntity[0]`
-   * are present.
-   */
-  const hasAvatar = avatarLinkAndEntities[0]
+  const [avatarLinkAndEntity] = avatarLinkAndEntities;
+  const hasAvatar = avatarLinkAndEntity
     ? {
-        // these are each arrays because each entity can have multiple revisions
-        linkEntity: avatarLinkAndEntities[0].linkEntity[0]!,
-        imageEntity: avatarLinkAndEntities[0]
-          .rightEntity![0]! as Entity<ImageFile>,
+        linkEntity: avatarLinkAndEntity.linkEntity,
+        imageEntity: avatarLinkAndEntity.rightEntity as Entity<ImageFile>,
       }
     : undefined;
 
-  const hasCoverImage = coverImageLinkAndEntities[0]
+  const [coverImageLinkAndEntity] = coverImageLinkAndEntities;
+  const hasCoverImage = coverImageLinkAndEntity
     ? {
-        // these are each arrays because each entity can have multiple revisions
-        linkEntity: coverImageLinkAndEntities[0].linkEntity[0]!,
-        imageEntity: coverImageLinkAndEntities[0]
-          .rightEntity![0]! as Entity<ImageFile>,
+        linkEntity: coverImageLinkAndEntity.linkEntity,
+        imageEntity: coverImageLinkAndEntity.rightEntity as Entity<ImageFile>,
       }
     : undefined;
 
-  const hasBio = hasBioLinkAndEntities[0]
+  const [hasBioLinkAndEntity] = hasBioLinkAndEntities;
+  const hasBio = hasBioLinkAndEntity
     ? {
-        // these are each arrays because each entity can have multiple revisions
-        linkEntity: hasBioLinkAndEntities[0]
-          .linkEntity[0]! as LinkEntity<HasBio>,
-        profileBioEntity: hasBioLinkAndEntities[0]
-          .rightEntity![0]! as Entity<ProfileBio>,
+        linkEntity: hasBioLinkAndEntity.linkEntity as LinkEntity<HasBio>,
+        profileBioEntity: hasBioLinkAndEntity.rightEntity as Entity<ProfileBio>,
       }
     : undefined;
 
diff --git a/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts b/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
index 96d75f0e50c..a6142357b93 100644
--- a/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
+++ b/apps/hash-frontend/src/pages/settings/integrations/linear/use-linear-integrations.ts
@@ -132,11 +132,10 @@ export const useLinearIntegrations = (): {
                * The target of a `syncLinearDataWith` link is a user or org
                * (web) entity, which is public – if the link is in the
                * subgraph its target must be too. A missing target means the
-               * subgraph is internally inconsistent (e.g. produced by non
-               * snapshot-consistent reads – see BE-644).
+               * subgraph is internally inconsistent.
                */
               throw new Error(
-                `Invariant violation: syncLinearDataWith link ${linkEntity.metadata.recordId.entityId} is missing its right (web) entity in the subgraph – see BE-644`,
+                `Invariant violation: syncLinearDataWith link ${linkEntity.metadata.recordId.entityId} is missing its right (web) entity in the subgraph`,
               );
             }
 
diff --git a/apps/plugin-browser/src/shared/get-user.ts b/apps/plugin-browser/src/shared/get-user.ts
index 2177537ee2f..2726173a553 100644
--- a/apps/plugin-browser/src/shared/get-user.ts
+++ b/apps/plugin-browser/src/shared/get-user.ts
@@ -229,11 +229,10 @@ export const getUser = (): Promise<LocalStorage["user"] | null> => {
           /**
            * Org entities are public – if the membership link is in the
            * subgraph, its right (org) entity must be too. A missing org
-           * entity means the subgraph is internally inconsistent (e.g.
-           * produced by non snapshot-consistent reads – see BE-644).
+           * entity means the subgraph is internally inconsistent.
            */
           throw new Error(
-            `Invariant violation: membership link ${linkEntity[0]?.metadata.recordId.entityId} is missing its right (org) entity in the subgraph – see BE-644`,
+            `Invariant violation: membership link ${linkEntity[0]?.metadata.recordId.entityId} is missing its right (org) entity in the subgraph`,
           );
         }
         const orgAvatar = getAvatarForEntity(