fix: stop V4 polling on cancellation

Author: MagMueller

apps/sim/blocks/blocks/browser_use.ts

@@ -17,6 +17,10 @@ export const BrowserUseBlock: BlockConfig<BrowserUseResponse> = {
   canvasPresentation: {
     defaultTitle: 'Browser Use',
     sentences: {
+      default: [
+        { text: 'Run the browser task', field: 'task', core: true },
+        { text: ', starting at', field: 'startUrl' },
+      ],
       byOperation: {
         browser_use_run_task: [
           { text: 'Run the legacy browser task', field: 'task', core: true },

apps/sim/tools/browser_use/run_v4.test.ts

@@ -114,6 +114,37 @@ describe('Browser Use V4 tool', () => {
     expect(fetchMock.mock.calls[2]?.[0]).toBe('https://api.browser-use.com/api/v4/runs/run-1')
   })
 
+  it('stops polling when the workflow is aborted', async () => {
+    const controller = new AbortController()
+    const fetchMock = vi
+      .fn<typeof fetch>()
+      .mockResolvedValueOnce(
+        jsonResponse({
+          id: 'run-1',
+          status: 'queued',
+          model: 'gpt-5.6-luna',
+          sessionId: 'session-1',
+          workspaceId: 'workspace-1',
+        })
+      )
+      .mockImplementationOnce(async (_input, init) => {
+        expect(init?.signal).toBe(controller.signal)
+        controller.abort(new Error('Workflow cancelled'))
+        return jsonResponse({ status: 'running' })
+      })
+    vi.stubGlobal('fetch', fetchMock)
+
+    const result = await runV4Tool.directExecution?.(
+      { task: 'Check the latest invoice', apiKey: 'test-key' },
+      controller.signal
+    )
+
+    expect(result?.success).toBe(false)
+    expect(result?.error).toBe('Error running V4 agent: Workflow cancelled')
+    expect(fetchMock).toHaveBeenCalledTimes(2)
+    expect(fetchMock.mock.calls[0]?.[1]?.signal).toBe(controller.signal)
+  })
+
   it('returns the upstream create error without polling', async () => {
     const fetchMock = vi.fn<typeof fetch>().mockResolvedValueOnce(
       new Response('Insufficient credits', {

apps/sim/tools/browser_use/run_v4.ts

@@ -87,14 +87,17 @@ async function readError(response: Response): Promise<string> {
 
 async function pollForCompletion(
   runId: string,
-  apiKey: string
+  apiKey: string,
+  signal?: AbortSignal
 ): Promise<{ summary?: V4RunSummary; error?: string }> {
   const deadline = Date.now() + MAX_POLL_TIME_MS
 
   for (;;) {
+    signal?.throwIfAborted()
     const statusResponse = await fetch(`${API_BASE}/runs/${runId}/status`, {
       method: 'GET',
       headers: { 'X-Browser-Use-API-Key': apiKey },
+      signal,
     })
     if (!statusResponse.ok) {
       return { error: `Failed to read run status: ${await readError(statusResponse)}` }
@@ -105,6 +108,7 @@ async function pollForCompletion(
       const runResponse = await fetch(`${API_BASE}/runs/${runId}`, {
         method: 'GET',
         headers: { 'X-Browser-Use-API-Key': apiKey },
+        signal,
       })
       if (!runResponse.ok) {
         return { error: `Failed to read completed run: ${await readError(runResponse)}` }
@@ -115,6 +119,7 @@ async function pollForCompletion(
     if (Date.now() >= deadline) {
       return { error: `Run did not complete within ${MAX_POLL_TIME_MS / 1000}s` }
     }
+    signal?.throwIfAborted()
     await sleep(POLL_INTERVAL_MS)
   }
 }
@@ -201,7 +206,10 @@ export const runV4Tool: ToolConfig<BrowserUseRunV4Params, BrowserUseRunV4Respons
     },
   },
 
-  directExecution: async (params: BrowserUseRunV4Params): Promise<ToolResponse> => {
+  directExecution: async (
+    params: BrowserUseRunV4Params,
+    signal?: AbortSignal
+  ): Promise<ToolResponse> => {
     const body: Record<string, unknown> = { task: params.task }
     if (params.model) body.model = params.model
     if (params.sessionId) body.sessionId = params.sessionId
@@ -226,6 +234,7 @@ export const runV4Tool: ToolConfig<BrowserUseRunV4Params, BrowserUseRunV4Respons
           'X-Browser-Use-API-Key': params.apiKey,
         },
         body: JSON.stringify(body),
+        signal,
       })
       if (!response.ok) {
         return {
@@ -237,7 +246,7 @@ export const runV4Tool: ToolConfig<BrowserUseRunV4Params, BrowserUseRunV4Respons
 
       const created = (await response.json()) as V4RunCreateResponse
       logger.info(`Created Browser Use V4 run ${created.id}`)
-      const completed = await pollForCompletion(created.id, params.apiKey)
+      const completed = await pollForCompletion(created.id, params.apiKey, signal)
       if (!completed.summary) {
         return { success: false, output: emptyOutput(created), error: completed.error }
       }