diff --git a/.turbo b/.turbo
new file mode 120000
index 00000000..0b7d9ca6
--- /dev/null
+++ b/.turbo
@@ -0,0 +1 @@
+/home/nathan/sandbox-agent/.turbo
\ No newline at end of file
diff --git a/Cargo.toml b/Cargo.toml
index 3907eee5..b4955a29 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -69,6 +69,8 @@ url = "2.5"
 regress = "0.10"
 include_dir = "0.7"
 base64 = "0.22"
+globset = "0.4"
+mime_guess = "2.0"
 
 # Code generation (build deps)
 typify = "0.4"
diff --git a/dist b/dist
new file mode 120000
index 00000000..f02d77f6
--- /dev/null
+++ b/dist
@@ -0,0 +1 @@
+/home/nathan/sandbox-agent/dist
\ No newline at end of file
diff --git a/node_modules b/node_modules
new file mode 120000
index 00000000..501480b2
--- /dev/null
+++ b/node_modules
@@ -0,0 +1 @@
+/home/nathan/sandbox-agent/node_modules
\ No newline at end of file
diff --git a/server/packages/sandbox-agent/Cargo.toml b/server/packages/sandbox-agent/Cargo.toml
index 5f45ad01..9690a7cc 100644
--- a/server/packages/sandbox-agent/Cargo.toml
+++ b/server/packages/sandbox-agent/Cargo.toml
@@ -36,6 +36,8 @@ tracing-logfmt.workspace = true
 tracing-subscriber.workspace = true
 include_dir.workspace = true
 base64.workspace = true
+globset.workspace = true
+mime_guess.workspace = true
 tempfile = { workspace = true, optional = true }
 
 [target.'cfg(unix)'.dependencies]
diff --git a/server/packages/sandbox-agent/src/filesystem.rs b/server/packages/sandbox-agent/src/filesystem.rs
new file mode 100644
index 00000000..12d3efc2
--- /dev/null
+++ b/server/packages/sandbox-agent/src/filesystem.rs
@@ -0,0 +1,448 @@
+use std::collections::VecDeque;
+use std::fs;
+use std::path::{Component, Path, PathBuf};
+use std::process::Command;
+use std::time::UNIX_EPOCH;
+
+use base64::{engine::general_purpose::STANDARD, Engine as _};
+use globset::{GlobBuilder, GlobSet, GlobSetBuilder};
+use mime_guess::MimeGuess;
+use serde::Serialize;
+
+use sandbox_agent_error::SandboxError;
+
+#[derive(Debug, Clone, Copy)]
+pub(crate) struct FileReadRange {
+    pub start: Option<u64>,
+    pub end: Option<u64>,
+}
+
+#[derive(Debug, Clone)]
+pub(crate) struct FileReadOptions {
+    pub path: String,
+    pub range: Option<FileReadRange>,
+}
+
+#[derive(Debug, Clone)]
+pub(crate) struct FileListOptions {
+    pub path: String,
+    pub glob: Option<String>,
+    pub depth: Option<usize>,
+    pub include_hidden: bool,
+    pub directories_only: bool,
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct WorkspaceFileNode {
+    pub name: String,
+    pub path: String,
+    pub absolute: String,
+    #[serde(rename = "type")]
+    pub entry_type: String,
+    pub ignored: bool,
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct WorkspaceFileContent {
+    #[serde(rename = "type")]
+    pub content_type: String,
+    pub content: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub encoding: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub mime_type: Option<String>,
+}
+
+#[derive(Debug, Serialize, Clone)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct WorkspaceVcsStatus {
+    pub status: String,
+    pub added: i64,
+    pub removed: i64,
+}
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct WorkspaceFileStatus {
+    pub path: String,
+    pub exists: bool,
+    #[serde(rename = "type")]
+    pub entry_type: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub size: Option<u64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub modified: Option<i64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub vcs: Option<WorkspaceVcsStatus>,
+}
+
+#[derive(Debug, Clone, Default)]
+pub(crate) struct WorkspaceFilesystemService;
+
+impl WorkspaceFilesystemService {
+    pub(crate) fn new() -> Self {
+        Self
+    }
+
+    pub(crate) fn scoped(
+        &self,
+        root: impl Into<PathBuf>,
+    ) -> Result<WorkspaceFilesystem, SandboxError> {
+        WorkspaceFilesystem::new(root.into())
+    }
+}
+
+#[derive(Debug, Clone)]
+pub(crate) struct WorkspaceFilesystem {
+    root: PathBuf,
+}
+
+impl WorkspaceFilesystem {
+    fn new(root: PathBuf) -> Result<Self, SandboxError> {
+        let root = fs::canonicalize(&root).unwrap_or(root);
+        if !root.exists() {
+            return Err(SandboxError::InvalidRequest {
+                message: "workspace root does not exist".to_string(),
+            });
+        }
+        if !root.is_dir() {
+            return Err(SandboxError::InvalidRequest {
+                message: "workspace root is not a directory".to_string(),
+            });
+        }
+        Ok(Self { root })
+    }
+
+    pub(crate) fn root(&self) -> &Path {
+        &self.root
+    }
+
+    pub(crate) fn list(
+        &self,
+        options: FileListOptions,
+    ) -> Result<Vec<WorkspaceFileNode>, SandboxError> {
+        let path = options.path.trim();
+        if path.is_empty() {
+            return Err(SandboxError::InvalidRequest {
+                message: "path is required".to_string(),
+            });
+        }
+        let directory = self.resolve_path(path, false)?;
+        let metadata = fs::metadata(&directory).map_err(|err| SandboxError::InvalidRequest {
+            message: format!("failed to access directory: {err}"),
+        })?;
+        if !metadata.is_dir() {
+            return Err(SandboxError::InvalidRequest {
+                message: "path is not a directory".to_string(),
+            });
+        }
+
+        let matcher = build_glob_matcher(options.glob.as_deref())?;
+        let max_depth = options.depth.unwrap_or(1);
+        let mut queue = VecDeque::new();
+        let mut entries = Vec::new();
+        queue.push_back((directory, 0usize));
+
+        while let Some((current_dir, depth)) = queue.pop_front() {
+            if depth >= max_depth {
+                continue;
+            }
+            let read_dir =
+                fs::read_dir(&current_dir).map_err(|err| SandboxError::InvalidRequest {
+                    message: format!("failed to read directory: {err}"),
+                })?;
+
+            for entry in read_dir {
+                let entry = entry.map_err(|err| SandboxError::InvalidRequest {
+                    message: format!("failed to read directory entry: {err}"),
+                })?;
+                let file_name = entry.file_name();
+                let name = file_name.to_string_lossy().to_string();
+                if !options.include_hidden && name.starts_with('.') {
+                    continue;
+                }
+                let file_type = entry
+                    .file_type()
+                    .map_err(|err| SandboxError::InvalidRequest {
+                        message: format!("failed to read file type: {err}"),
+                    })?;
+                let entry_path = entry.path();
+
+                if file_type.is_dir() && !options.include_hidden && is_hidden_dir(&entry_path) {
+                    continue;
+                }
+
+                let relative_path = path_relative_to_root(&self.root, &entry_path)?;
+                if let Some(matcher) = matcher.as_ref() {
+                    if !matcher.is_match(relative_path.as_str()) {
+                        if file_type.is_dir() {
+                            if depth + 1 < max_depth {
+                                queue.push_back((entry_path.clone(), depth + 1));
+                            }
+                        }
+                        continue;
+                    }
+                }
+
+                if options.directories_only && !file_type.is_dir() {
+                    continue;
+                }
+
+                let entry_type = if file_type.is_dir() {
+                    "directory"
+                } else {
+                    "file"
+                };
+
+                entries.push(WorkspaceFileNode {
+                    name,
+                    path: relative_path,
+                    absolute: entry_path.to_string_lossy().to_string(),
+                    entry_type: entry_type.to_string(),
+                    ignored: false,
+                });
+
+                if file_type.is_dir() && depth + 1 < max_depth {
+                    queue.push_back((entry_path, depth + 1));
+                }
+            }
+        }
+
+        entries.sort_by(|a, b| a.path.cmp(&b.path));
+        Ok(entries)
+    }
+
+    pub(crate) fn read(
+        &self,
+        options: FileReadOptions,
+    ) -> Result<WorkspaceFileContent, SandboxError> {
+        let path = options.path.trim();
+        if path.is_empty() {
+            return Err(SandboxError::InvalidRequest {
+                message: "path is required".to_string(),
+            });
+        }
+        let file_path = self.resolve_path(path, false)?;
+        let metadata = fs::metadata(&file_path).map_err(|err| SandboxError::InvalidRequest {
+            message: format!("failed to access file: {err}"),
+        })?;
+        if !metadata.is_file() {
+            return Err(SandboxError::InvalidRequest {
+                message: "path is not a file".to_string(),
+            });
+        }
+        let mut bytes = fs::read(&file_path).map_err(|err| SandboxError::InvalidRequest {
+            message: format!("failed to read file: {err}"),
+        })?;
+
+        if let Some(range) = options.range {
+            bytes = apply_byte_range(bytes, range)?;
+        }
+
+        let mime = MimeGuess::from_path(&file_path)
+            .first_or_octet_stream()
+            .essence_str()
+            .to_string();
+        if let Ok(text) = String::from_utf8(bytes.clone()) {
+            return Ok(WorkspaceFileContent {
+                content_type: "text".to_string(),
+                content: text,
+                encoding: None,
+                mime_type: Some(mime),
+            });
+        }
+
+        Ok(WorkspaceFileContent {
+            content_type: "binary".to_string(),
+            content: STANDARD.encode(bytes),
+            encoding: Some("base64".to_string()),
+            mime_type: Some(mime),
+        })
+    }
+
+    pub(crate) fn status(&self) -> Result<Vec<WorkspaceFileStatus>, SandboxError> {
+        if !self.root.join(".git").exists() {
+            return Ok(Vec::new());
+        }
+        let output = Command::new("git")
+            .arg("status")
+            .arg("--porcelain=v1")
+            .arg("-z")
+            .current_dir(&self.root)
+            .output()
+            .map_err(|err| SandboxError::StreamError {
+                message: format!("failed to run git status: {err}"),
+            })?;
+        if !output.status.success() {
+            return Err(SandboxError::StreamError {
+                message: format!("git status failed: {}", output.status),
+            });
+        }
+
+        let stdout = String::from_utf8_lossy(&output.stdout);
+        let mut entries = Vec::new();
+        for record in stdout.split('\0').filter(|line| !line.is_empty()) {
+            let (status_code, path) = parse_git_porcelain_entry(record);
+            let Some(path) = path else {
+                continue;
+            };
+            let status = map_git_status(status_code);
+            let absolute = self.root.join(&path);
+            let (exists, entry_type, size, modified) = file_metadata(&absolute);
+            entries.push(WorkspaceFileStatus {
+                path,
+                exists,
+                entry_type,
+                size,
+                modified,
+                vcs: Some(WorkspaceVcsStatus {
+                    status,
+                    added: 0,
+                    removed: 0,
+                }),
+            });
+        }
+
+        Ok(entries)
+    }
+
+    fn resolve_path(&self, input: &str, allow_missing: bool) -> Result<PathBuf, SandboxError> {
+        let input_path = PathBuf::from(input);
+        if input_path
+            .components()
+            .any(|component| matches!(component, Component::ParentDir))
+        {
+            return Err(SandboxError::InvalidRequest {
+                message: "path traversal is not allowed".to_string(),
+            });
+        }
+
+        let joined = if input_path.is_absolute() {
+            input_path
+        } else {
+            self.root.join(input_path)
+        };
+
+        let normalized = if allow_missing {
+            normalize_path(&joined)
+        } else {
+            fs::canonicalize(&joined).unwrap_or(joined.clone())
+        };
+
+        if !normalized.starts_with(&self.root) {
+            return Err(SandboxError::InvalidRequest {
+                message: "path is outside the workspace".to_string(),
+            });
+        }
+
+        Ok(normalized)
+    }
+}
+
+fn build_glob_matcher(glob: Option<&str>) -> Result<Option<GlobSet>, SandboxError> {
+    let Some(pattern) = glob else {
+        return Ok(None);
+    };
+    let mut builder = GlobSetBuilder::new();
+    let glob = GlobBuilder::new(pattern)
+        .literal_separator(true)
+        .build()
+        .map_err(|err| SandboxError::InvalidRequest {
+            message: format!("invalid glob pattern: {err}"),
+        })?;
+    builder.add(glob);
+    let set = builder
+        .build()
+        .map_err(|err| SandboxError::InvalidRequest {
+            message: format!("invalid glob matcher: {err}"),
+        })?;
+    Ok(Some(set))
+}
+
+fn apply_byte_range(bytes: Vec<u8>, range: FileReadRange) -> Result<Vec<u8>, SandboxError> {
+    let len = bytes.len() as u64;
+    let start = range.start.unwrap_or(0);
+    let end = range.end.unwrap_or(len);
+    if start > end || end > len {
+        return Err(SandboxError::InvalidRequest {
+            message: "invalid byte range".to_string(),
+        });
+    }
+    Ok(bytes[start as usize..end as usize].to_vec())
+}
+
+fn normalize_path(path: &Path) -> PathBuf {
+    let mut normalized = PathBuf::new();
+    for component in path.components() {
+        match component {
+            Component::Prefix(prefix) => normalized.push(prefix.as_os_str()),
+            Component::RootDir => normalized.push(Path::new(std::path::MAIN_SEPARATOR_STR)),
+            Component::CurDir => {}
+            Component::ParentDir => {
+                normalized.pop();
+            }
+            Component::Normal(value) => normalized.push(value),
+        }
+    }
+    normalized
+}
+
+fn path_relative_to_root(root: &Path, path: &Path) -> Result<String, SandboxError> {
+    let relative = path
+        .strip_prefix(root)
+        .map_err(|_| SandboxError::InvalidRequest {
+            message: "path is outside the workspace".to_string(),
+        })?;
+    Ok(relative.to_string_lossy().to_string())
+}
+
+fn is_hidden_dir(path: &Path) -> bool {
+    path.file_name()
+        .and_then(|name| name.to_str())
+        .map(|name| name.starts_with('.'))
+        .unwrap_or(false)
+}
+
+fn file_metadata(path: &Path) -> (bool, String, Option<u64>, Option<i64>) {
+    let Ok(metadata) = fs::metadata(path) else {
+        return (false, "file".to_string(), None, None);
+    };
+    let entry_type = if metadata.is_dir() {
+        "directory"
+    } else {
+        "file"
+    };
+    let modified = metadata
+        .modified()
+        .ok()
+        .and_then(|time| time.duration_since(UNIX_EPOCH).ok())
+        .map(|duration| duration.as_millis() as i64);
+    (true, entry_type.to_string(), Some(metadata.len()), modified)
+}
+
+fn parse_git_porcelain_entry(entry: &str) -> (&str, Option<String>) {
+    if entry.len() < 3 {
+        return ("", None);
+    }
+    let status = &entry[0..2];
+    let path = entry[3..].trim();
+    if path.is_empty() {
+        return (status, None);
+    }
+    if let Some((_, new_path)) = path.split_once(" -> ") {
+        return (status, Some(new_path.to_string()));
+    }
+    (status, Some(path.to_string()))
+}
+
+fn map_git_status(status: &str) -> String {
+    if status.contains('D') {
+        return "deleted".to_string();
+    }
+    if status.contains('A') || status.contains('?') {
+        return "added".to_string();
+    }
+    "modified".to_string()
+}
diff --git a/server/packages/sandbox-agent/src/lib.rs b/server/packages/sandbox-agent/src/lib.rs
index 8c113431..72361053 100644
--- a/server/packages/sandbox-agent/src/lib.rs
+++ b/server/packages/sandbox-agent/src/lib.rs
@@ -2,6 +2,7 @@
 
 mod agent_server_logs;
 pub mod credentials;
+pub(crate) mod filesystem;
 pub mod opencode_compat;
 pub mod router;
 pub mod server_logs;
diff --git a/server/packages/sandbox-agent/src/opencode_compat.rs b/server/packages/sandbox-agent/src/opencode_compat.rs
index 55b70505..7642ed18 100644
--- a/server/packages/sandbox-agent/src/opencode_compat.rs
+++ b/server/packages/sandbox-agent/src/opencode_compat.rs
@@ -13,7 +13,7 @@ use std::str::FromStr;
 use axum::extract::{Path, Query, State};
 use axum::http::{HeaderMap, StatusCode};
 use axum::response::sse::{Event, KeepAlive};
-use axum::response::{IntoResponse, Sse};
+use axum::response::{IntoResponse, Response, Sse};
 use axum::routing::{get, patch, post, put};
 use axum::{Json, Router};
 use futures::stream;
@@ -23,6 +23,7 @@ use tokio::sync::{broadcast, Mutex};
 use tokio::time::interval;
 use utoipa::{IntoParams, OpenApi, ToSchema};
 
+use crate::filesystem::{FileListOptions, FileReadOptions, FileReadRange, WorkspaceFileStatus};
 use crate::router::{AppState, CreateSessionRequest, PermissionReply};
 use sandbox_agent_error::SandboxError;
 use sandbox_agent_agent_management::agents::AgentId;
@@ -491,10 +492,22 @@ struct FindSymbolsQuery {
     query: Option<String>,
 }
 
+#[derive(Debug, Deserialize, IntoParams)]
+struct FileListQuery {
+    directory: Option<String>,
+    path: Option<String>,
+    glob: Option<String>,
+    depth: Option<usize>,
+    hidden: Option<bool>,
+    directories: Option<bool>,
+}
+
 #[derive(Debug, Deserialize, IntoParams)]
 struct FileContentQuery {
     directory: Option<String>,
     path: Option<String>,
+    start: Option<u64>,
+    end: Option<u64>,
 }
 
 #[derive(Debug, Serialize, Deserialize, ToSchema)]
@@ -769,6 +782,37 @@ fn sandbox_error_response(err: SandboxError) -> (StatusCode, Json<Value>) {
     }
 }
 
+fn filesystem_error_response(err: SandboxError) -> Response {
+    match err {
+        SandboxError::InvalidRequest { message } => bad_request(&message).into_response(),
+        SandboxError::StreamError { message } => internal_error(&message).into_response(),
+        other => internal_error(&other.to_string()).into_response(),
+    }
+}
+
+#[derive(Debug, Serialize)]
+struct OpenCodeFileStatusEntry {
+    path: String,
+    added: i64,
+    removed: i64,
+    status: String,
+}
+
+fn opencode_status_entries(entries: Vec<WorkspaceFileStatus>) -> Vec<OpenCodeFileStatusEntry> {
+    entries
+        .into_iter()
+        .filter_map(|entry| {
+            let vcs = entry.vcs?;
+            Some(OpenCodeFileStatusEntry {
+                path: entry.path,
+                added: vcs.added,
+                removed: vcs.removed,
+                status: vcs.status,
+            })
+        })
+        .collect()
+}
+
 fn parse_permission_reply_value(value: Option<&str>) -> Result<PermissionReply, String> {
     let value = value.unwrap_or("once").to_ascii_lowercase();
     match value.as_str() {
@@ -3754,8 +3798,35 @@ async fn oc_pty_connect(Path(_pty_id): Path<String>) -> impl IntoResponse {
     responses((status = 200)),
     tag = "opencode"
 )]
-async fn oc_file_list() -> impl IntoResponse {
-    (StatusCode::OK, Json(json!([])))
+async fn oc_file_list(
+    State(state): State<Arc<OpenCodeAppState>>,
+    headers: HeaderMap,
+    Query(query): Query<FileListQuery>,
+) -> impl IntoResponse {
+    let Some(path) = query.path else {
+        return bad_request("path is required").into_response();
+    };
+    let directory = state.opencode.directory_for(&headers, query.directory.as_ref());
+    let filesystem = match state
+        .inner
+        .session_manager()
+        .workspace_filesystem()
+        .scoped(directory)
+    {
+        Ok(filesystem) => filesystem,
+        Err(err) => return filesystem_error_response(err),
+    };
+    let options = FileListOptions {
+        path,
+        glob: query.glob,
+        depth: query.depth,
+        include_hidden: query.hidden.unwrap_or(false),
+        directories_only: query.directories.unwrap_or(false),
+    };
+    match filesystem.list(options) {
+        Ok(entries) => (StatusCode::OK, Json(entries)).into_response(),
+        Err(err) => filesystem_error_response(err),
+    }
 }
 
 #[utoipa::path(
@@ -3764,18 +3835,37 @@ async fn oc_file_list() -> impl IntoResponse {
     responses((status = 200)),
     tag = "opencode"
 )]
-async fn oc_file_content(Query(query): Query<FileContentQuery>) -> impl IntoResponse {
-    if query.path.is_none() {
+async fn oc_file_content(
+    State(state): State<Arc<OpenCodeAppState>>,
+    headers: HeaderMap,
+    Query(query): Query<FileContentQuery>,
+) -> impl IntoResponse {
+    let Some(path) = query.path else {
         return bad_request("path is required").into_response();
+    };
+    let directory = state.opencode.directory_for(&headers, query.directory.as_ref());
+    let filesystem = match state
+        .inner
+        .session_manager()
+        .workspace_filesystem()
+        .scoped(directory)
+    {
+        Ok(filesystem) => filesystem,
+        Err(err) => return filesystem_error_response(err),
+    };
+    let range = if query.start.is_some() || query.end.is_some() {
+        Some(FileReadRange {
+            start: query.start,
+            end: query.end,
+        })
+    } else {
+        None
+    };
+    let options = FileReadOptions { path, range };
+    match filesystem.read(options) {
+        Ok(content) => (StatusCode::OK, Json(content)).into_response(),
+        Err(err) => filesystem_error_response(err),
     }
-    (
-        StatusCode::OK,
-        Json(json!({
-            "type": "text",
-            "content": "",
-        })),
-    )
-        .into_response()
 }
 
 #[utoipa::path(
@@ -3784,8 +3874,28 @@ async fn oc_file_content(Query(query): Query<FileContentQuery>) -> impl IntoResp
     responses((status = 200)),
     tag = "opencode"
 )]
-async fn oc_file_status() -> impl IntoResponse {
-    (StatusCode::OK, Json(json!([]))).into_response()
+async fn oc_file_status(
+    State(state): State<Arc<OpenCodeAppState>>,
+    headers: HeaderMap,
+    Query(query): Query<DirectoryQuery>,
+) -> impl IntoResponse {
+    let directory = state.opencode.directory_for(&headers, query.directory.as_ref());
+    let filesystem = match state
+        .inner
+        .session_manager()
+        .workspace_filesystem()
+        .scoped(directory)
+    {
+        Ok(filesystem) => filesystem,
+        Err(err) => return filesystem_error_response(err),
+    };
+    match filesystem.status() {
+        Ok(entries) => {
+            let files = opencode_status_entries(entries);
+            (StatusCode::OK, Json(json!(files))).into_response()
+        }
+        Err(err) => filesystem_error_response(err),
+    }
 }
 
 #[utoipa::path(
diff --git a/server/packages/sandbox-agent/src/router.rs b/server/packages/sandbox-agent/src/router.rs
index 3ca437a7..d273b084 100644
--- a/server/packages/sandbox-agent/src/router.rs
+++ b/server/packages/sandbox-agent/src/router.rs
@@ -39,6 +39,7 @@ use tracing::Span;
 use utoipa::{Modify, OpenApi, ToSchema};
 
 use crate::agent_server_logs::AgentServerLogs;
+use crate::filesystem::WorkspaceFilesystemService;
 use crate::opencode_compat::{build_opencode_router, OpenCodeAppState};
 use crate::ui;
 use sandbox_agent_agent_management::agents::{
@@ -818,6 +819,7 @@ pub(crate) struct SessionManager {
     sessions: Mutex<Vec<SessionState>>,
     server_manager: Arc<AgentServerManager>,
     http_client: Client,
+    filesystem: WorkspaceFilesystemService,
 }
 
 /// Shared Codex app-server process that handles multiple sessions via JSON-RPC.
@@ -1538,6 +1540,7 @@ impl SessionManager {
             sessions: Mutex::new(Vec::new()),
             server_manager,
             http_client: Client::new(),
+            filesystem: WorkspaceFilesystemService::new(),
         }
     }
 
@@ -1562,6 +1565,10 @@ impl SessionManager {
         logs.read_stderr()
     }
 
+    pub(crate) fn workspace_filesystem(&self) -> &WorkspaceFilesystemService {
+        &self.filesystem
+    }
+
     pub(crate) async fn create_session(
         self: &Arc<Self>,
         session_id: String,
diff --git a/server/packages/sandbox-agent/tests/opencode-compat/filesystem.test.ts b/server/packages/sandbox-agent/tests/opencode-compat/filesystem.test.ts
new file mode 100644
index 00000000..68f174dd
--- /dev/null
+++ b/server/packages/sandbox-agent/tests/opencode-compat/filesystem.test.ts
@@ -0,0 +1,73 @@
+import { describe, it, expect, beforeAll, afterEach, beforeEach } from "vitest";
+import { createOpencodeClient, type OpencodeClient } from "@opencode-ai/sdk";
+import { spawnSandboxAgent, buildSandboxAgent, type SandboxAgentHandle } from "./helpers/spawn";
+import { mkdtemp, mkdir, writeFile, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+describe("OpenCode-compatible filesystem API", () => {
+  let handle: SandboxAgentHandle;
+  let client: OpencodeClient;
+  let tempDir: string;
+
+  beforeAll(async () => {
+    await buildSandboxAgent();
+  });
+
+  beforeEach(async () => {
+    tempDir = await mkdtemp(join(tmpdir(), "opencode-fs-"));
+    await writeFile(join(tempDir, "hello.txt"), "hello world\n");
+    await mkdir(join(tempDir, "nested"), { recursive: true });
+    await writeFile(join(tempDir, "nested", "child.txt"), "child content\n");
+
+    handle = await spawnSandboxAgent({
+      opencodeCompat: true,
+      env: {
+        OPENCODE_COMPAT_DIRECTORY: tempDir,
+        OPENCODE_COMPAT_WORKTREE: tempDir,
+      },
+    });
+
+    client = createOpencodeClient({
+      baseUrl: `${handle.baseUrl}/opencode`,
+      headers: { Authorization: `Bearer ${handle.token}` },
+    });
+  });
+
+  afterEach(async () => {
+    await handle?.dispose();
+    if (tempDir) {
+      await rm(tempDir, { recursive: true, force: true });
+    }
+  });
+
+  it("lists files within the workspace", async () => {
+    const response = await client.file.list({
+      query: { path: "." },
+    });
+
+    expect(response.data).toBeDefined();
+    expect(Array.isArray(response.data)).toBe(true);
+    const paths = (response.data ?? []).map((entry) => entry.path);
+    expect(paths).toContain("hello.txt");
+    expect(paths).toContain("nested");
+  });
+
+  it("reads file content", async () => {
+    const response = await client.file.read({
+      query: { path: "hello.txt" },
+    });
+
+    expect(response.data).toBeDefined();
+    expect(response.data?.type).toBe("text");
+    expect(response.data?.content).toContain("hello world");
+  });
+
+  it("rejects paths outside the workspace", async () => {
+    const response = await client.file.read({
+      query: { path: "../outside.txt" },
+    });
+
+    expect(response.error).toBeDefined();
+  });
+});
diff --git a/target b/target
new file mode 120000
index 00000000..3d6ad8cf
--- /dev/null
+++ b/target
@@ -0,0 +1 @@
+/home/nathan/sandbox-agent/target
\ No newline at end of file