diff --git a/packages/client/test-runtime/src/workspaces.ts b/packages/client/test-runtime/src/workspaces.ts
index 3505de0853..6c1a9d0aad 100644
--- a/packages/client/test-runtime/src/workspaces.ts
+++ b/packages/client/test-runtime/src/workspaces.ts
@@ -115,10 +115,13 @@ export class TestWorkspaces implements IWorkspaces {
    * @param path - absolute directory to list; absent lists the home level.
    * @returns the level's listing.
    */
-  async listDirectory(path?: string, _signal?: AbortSignal): Promise<DirectoryListing> {
-    this.calls.push({ method: 'listDirectory', args: [path] })
+  async listDirectory(path?: string, signal?: AbortSignal): Promise<DirectoryListing> {
+    // The signal is recorded and forwarded like the production face passes
+    // it to the wire, so cancellation integration tests can observe or
+    // reject on a superseded scan.
+    this.calls.push({ method: 'listDirectory', args: [path, signal] })
     const stub = this.stubs.get('listDirectory')
-    if (stub !== undefined) return await (stub(path) as Promise<DirectoryListing>)
+    if (stub !== undefined) return await (stub(path, signal) as Promise<DirectoryListing>)
     // The chain runs root-to-target inclusive, per the DirectoryListing
     // contract — a bare root crumb would mislabel the level in browsers
     // driven by this double.
diff --git a/packages/client/test-runtime/tests/runtime.spec.tsx b/packages/client/test-runtime/tests/runtime.spec.tsx
index a6f22a85fe..b170f69ba2 100644
--- a/packages/client/test-runtime/tests/runtime.spec.tsx
+++ b/packages/client/test-runtime/tests/runtime.spec.tsx
@@ -329,16 +329,22 @@ describe('workspaces', () => {
     await expect(runtime.workspaces.listDirectory()).resolves.toMatchObject({ path: '/home/test', entries: [] })
     await expect(runtime.workspaces.listDirectory('/home/test')).resolves.toMatchObject({ path: '/home/test' })
     await expect(runtime.workspaces.createDirectory('/home/test', 'fresh')).resolves.toBe('/home/test/fresh')
+    // The recorded signal seat mirrors the production face (undefined here;
+    // cancellation tests pass and observe a real one).
     expect(runtime.workspaces.calls).toEqual([
-      { method: 'listDirectory', args: [undefined] },
-      { method: 'listDirectory', args: ['/home/test'] },
+      { method: 'listDirectory', args: [undefined, undefined] },
+      { method: 'listDirectory', args: ['/home/test', undefined] },
       { method: 'createDirectory', args: ['/home/test', 'fresh'] },
     ])
     // Stubs replace the defaults like every sibling method.
     const listing = { path: '/x', home: '/x', crumbs: [], entries: [] }
-    runtime.workspaces.stub('listDirectory', vi.fn(() => Promise.resolve(listing as never)))
+    const listStub = vi.fn(() => Promise.resolve(listing as never))
+    runtime.workspaces.stub('listDirectory', listStub)
     runtime.workspaces.stub('createDirectory', vi.fn(() => Promise.resolve('/x/made' as never)))
-    await expect(runtime.workspaces.listDirectory('/x')).resolves.toBe(listing)
+    const scan = new AbortController()
+    await expect(runtime.workspaces.listDirectory('/x', scan.signal)).resolves.toBe(listing)
+    // The stub receives the signal too, like the production face gives the wire.
+    expect(listStub).toHaveBeenLastCalledWith('/x', scan.signal)
     await expect(runtime.workspaces.createDirectory('/x', 'made')).resolves.toBe('/x/made')
     await runtime.dispose()
   })