chore: import upstream snapshot with attribution

apps/sim/lib/copilot/request/go/stream.test.ts

@@ -0,0 +1,869 @@
+/**
+ * @vitest-environment node
+ */
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import {
+  MothershipStreamV1CompletionStatus,
+  MothershipStreamV1EventType,
+  MothershipStreamV1ToolExecutor,
+  MothershipStreamV1ToolMode,
+  MothershipStreamV1ToolOutcome,
+  MothershipStreamV1ToolPhase,
+} from '@/lib/copilot/generated/mothership-stream-v1'
+
+vi.mock('@/lib/copilot/request/session', async () => {
+  const actual = await vi.importActual<typeof import('@/lib/copilot/request/session')>(
+    '@/lib/copilot/request/session'
+  )
+  return {
+    ...actual,
+    hasAbortMarker: vi.fn().mockResolvedValue(false),
+    upsertFilePreviewSession: vi.fn(async (session) => session),
+  }
+})
+
+const resolveWorkspaceFileReferenceMock = vi.hoisted(() => vi.fn())
+
+vi.mock('@/lib/uploads/contexts/workspace/workspace-file-manager', () => ({
+  resolveWorkspaceFileReference: resolveWorkspaceFileReferenceMock,
+}))
+
+vi.mock('@/lib/copilot/tools/server/files/file-preview', async () => {
+  const actual = await vi.importActual<
+    typeof import('@/lib/copilot/tools/server/files/file-preview')
+  >('@/lib/copilot/tools/server/files/file-preview')
+  return {
+    ...actual,
+    loadWorkspaceFileTextForPreview: vi.fn().mockResolvedValue(''),
+  }
+})
+
+import {
+  buildPreviewContentUpdate,
+  decodeJsonStringPrefix,
+  extractEditContent,
+  runStreamLoop,
+} from '@/lib/copilot/request/go/stream'
+import { AbortReason, createEvent, hasAbortMarker } from '@/lib/copilot/request/session'
+import { RequestTraceV1Outcome, TraceCollector } from '@/lib/copilot/request/trace'
+import type { ExecutionContext, StreamingContext } from '@/lib/copilot/request/types'
+
+function createSseResponse(events: unknown[]): Response {
+  const payload = events.map((event) => `data: ${JSON.stringify(event)}\n\n`).join('')
+
+  return new Response(
+    new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(new TextEncoder().encode(payload))
+        controller.close()
+      },
+    }),
+    {
+      status: 200,
+      headers: {
+        'Content-Type': 'text/event-stream',
+      },
+    }
+  )
+}
+
+function createRawSseResponse(payload: string): Response {
+  return new Response(
+    new ReadableStream<Uint8Array>({
+      start(controller) {
+        controller.enqueue(new TextEncoder().encode(payload))
+        controller.close()
+      },
+    }),
+    {
+      status: 200,
+      headers: {
+        'Content-Type': 'text/event-stream',
+      },
+    }
+  )
+}
+
+function createStreamingContext(): StreamingContext {
+  return {
+    messageId: 'msg-1',
+    accumulatedContent: '',
+    finalAssistantContent: '',
+    sawMainToolCall: false,
+    contentBlocks: [],
+    toolCalls: new Map(),
+    pendingToolPromises: new Map(),
+    currentThinkingBlock: null,
+    subagentThinkingBlocks: new Map(),
+    isInThinkingBlock: false,
+    subAgentContent: {},
+    subAgentToolCalls: {},
+    pendingContent: '',
+    streamComplete: false,
+    wasAborted: false,
+    errors: [],
+    activeFileIntents: new Map(),
+    trace: new TraceCollector(),
+  }
+}
+
+describe('copilot go stream helpers', () => {
+  beforeEach(() => {
+    vi.stubGlobal('fetch', vi.fn())
+    resolveWorkspaceFileReferenceMock.mockReset()
+    resolveWorkspaceFileReferenceMock.mockResolvedValue(null)
+  })
+
+  afterEach(() => {
+    vi.unstubAllGlobals()
+  })
+
+  it('decodes complete escapes and stops at incomplete unicode escapes', () => {
+    expect(decodeJsonStringPrefix('hello\\nworld')).toBe('hello\nworld')
+    expect(decodeJsonStringPrefix('emoji \\u263A')).toBe('emoji ☺')
+    expect(decodeJsonStringPrefix('partial \\u26')).toBe('partial ')
+  })
+
+  it('extracts the streamed edit_content prefix from partial JSON', () => {
+    expect(extractEditContent('{"content":"hello\\nwor')).toBe('hello\nwor')
+    expect(extractEditContent('{"content":"tab\\tvalue"}')).toBe('tab\tvalue')
+  })
+
+  it('emits full snapshots for append (sidebar viewer uses replace mode; no delta merge)', () => {
+    expect(buildPreviewContentUpdate('hello', 'hello world', 100, 200, 'append')).toEqual({
+      content: 'hello world',
+      contentMode: 'snapshot',
+      lastSnapshotAt: 200,
+    })
+  })
+
+  it('emits deltas for update when the preview extends the previous text', () => {
+    expect(buildPreviewContentUpdate('hello', 'hello world', 100, 200, 'update')).toEqual({
+      content: ' world',
+      contentMode: 'delta',
+      lastSnapshotAt: 100,
+    })
+  })
+
+  it('falls back to snapshots for patches and divergent content', () => {
+    expect(buildPreviewContentUpdate('hello', 'goodbye', 100, 200, 'update')).toEqual({
+      content: 'goodbye',
+      contentMode: 'snapshot',
+      lastSnapshotAt: 200,
+    })
+
+    expect(buildPreviewContentUpdate('hello', 'hello world', 100, 200, 'patch')).toEqual({
+      content: 'hello world',
+      contentMode: 'snapshot',
+      lastSnapshotAt: 200,
+    })
+  })
+
+  it('hydrates path-based workspace_file edits into file preview events before edit_content streams', async () => {
+    resolveWorkspaceFileReferenceMock.mockResolvedValue({
+      id: 'file-1',
+      name: 'notes.md',
+    })
+
+    const workspaceFileCall = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'workspace-file-path-1',
+        toolName: 'workspace_file',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.call,
+        arguments: {
+          operation: 'update',
+          target: { kind: 'path', path: 'files/notes.md' },
+          title: 'Update notes',
+        },
+      },
+    })
+    const workspaceFileResult = createEvent({
+      streamId: 'stream-1',
+      cursor: '2',
+      seq: 2,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'workspace-file-path-1',
+        toolName: 'workspace_file',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.result,
+        success: true,
+        output: {
+          success: true,
+          data: { id: 'file-1', name: 'notes.md', operation: 'update' },
+        },
+      },
+    })
+    const editContentDelta = createEvent({
+      streamId: 'stream-1',
+      cursor: '3',
+      seq: 3,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'edit-content-path-1',
+        toolName: 'edit_content',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.args_delta,
+        argumentsDelta: '{"content":"hello world',
+      },
+    })
+    const editContentResult = createEvent({
+      streamId: 'stream-1',
+      cursor: '4',
+      seq: 4,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'edit-content-path-1',
+        toolName: 'edit_content',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.result,
+        success: true,
+        output: {
+          success: true,
+          data: { id: 'file-1', name: 'notes.md' },
+        },
+      },
+    })
+    const complete = createEvent({
+      streamId: 'stream-1',
+      cursor: '5',
+      seq: 5,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.complete,
+      payload: {
+        status: MothershipStreamV1CompletionStatus.complete,
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(
+      createSseResponse([
+        workspaceFileCall,
+        workspaceFileResult,
+        editContentDelta,
+        editContentResult,
+        complete,
+      ])
+    )
+
+    const onEvent = vi.fn()
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+      workspaceId: 'workspace-1',
+      messageId: 'msg-1',
+    }
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      onEvent,
+      timeout: 1000,
+    })
+
+    const previewEvents = onEvent.mock.calls
+      .map(([event]) => event)
+      .filter(
+        (event) =>
+          event.type === MothershipStreamV1EventType.tool && 'previewPhase' in event.payload
+      )
+
+    expect(previewEvents.map((event) => event.payload.previewPhase)).toEqual([
+      'file_preview_start',
+      'file_preview_target',
+      'file_preview_content',
+      'file_preview_complete',
+    ])
+    expect(previewEvents[1].payload).toMatchObject({
+      previewPhase: 'file_preview_target',
+      target: { kind: 'file_id', fileId: 'file-1', fileName: 'notes.md' },
+    })
+    expect(previewEvents[2].payload).toMatchObject({
+      previewPhase: 'file_preview_content',
+      fileId: 'file-1',
+      targetKind: 'file_id',
+      content: 'hello world',
+    })
+    expect(previewEvents[3].payload).toMatchObject({
+      previewPhase: 'file_preview_complete',
+      fileId: 'file-1',
+    })
+    expect(resolveWorkspaceFileReferenceMock).toHaveBeenCalledWith('workspace-1', 'files/notes.md')
+  })
+
+  it('resolves workflow alias paths to the backing file before streaming previews', async () => {
+    resolveWorkspaceFileReferenceMock.mockResolvedValue({
+      id: 'changelog-file-1',
+      name: 'workflow-1.md',
+    })
+
+    const workspaceFileCall = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'workspace-file-alias-1',
+        toolName: 'workspace_file',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.call,
+        arguments: {
+          operation: 'append',
+          target: { kind: 'path', path: 'workflows/My%20Workflow/changelog.md' },
+          title: 'Update changelog',
+        },
+      },
+    })
+    const editContentDelta = createEvent({
+      streamId: 'stream-1',
+      cursor: '2',
+      seq: 2,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'edit-content-alias-1',
+        toolName: 'edit_content',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.args_delta,
+        argumentsDelta: '{"content":"\\n- Added a workflow step',
+      },
+    })
+    const editContentResult = createEvent({
+      streamId: 'stream-1',
+      cursor: '3',
+      seq: 3,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'edit-content-alias-1',
+        toolName: 'edit_content',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.result,
+        success: true,
+        output: {
+          success: true,
+          data: { id: 'changelog-file-1', name: 'workflow-1.md' },
+        },
+      },
+    })
+    const complete = createEvent({
+      streamId: 'stream-1',
+      cursor: '4',
+      seq: 4,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.complete,
+      payload: {
+        status: MothershipStreamV1CompletionStatus.complete,
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(
+      createSseResponse([workspaceFileCall, editContentDelta, editContentResult, complete])
+    )
+
+    const onEvent = vi.fn()
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+      workspaceId: 'workspace-1',
+      messageId: 'msg-1',
+    }
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      onEvent,
+      timeout: 1000,
+    })
+
+    const previewEvents = onEvent.mock.calls
+      .map(([event]) => event)
+      .filter(
+        (event) =>
+          event.type === MothershipStreamV1EventType.tool && 'previewPhase' in event.payload
+      )
+
+    expect(previewEvents.map((event) => event.payload.previewPhase)).toEqual([
+      'file_preview_start',
+      'file_preview_target',
+      'file_preview_content',
+      'file_preview_complete',
+    ])
+    expect(previewEvents[1].payload).toMatchObject({
+      previewPhase: 'file_preview_target',
+      target: { kind: 'file_id', fileId: 'changelog-file-1', fileName: 'workflow-1.md' },
+    })
+    expect(previewEvents[2].payload).toMatchObject({
+      previewPhase: 'file_preview_content',
+      fileId: 'changelog-file-1',
+      targetKind: 'file_id',
+      content: '\n- Added a workflow step',
+    })
+    expect(previewEvents[3].payload).toMatchObject({
+      previewPhase: 'file_preview_complete',
+      fileId: 'changelog-file-1',
+    })
+    expect(resolveWorkspaceFileReferenceMock).toHaveBeenCalledWith(
+      'workspace-1',
+      'workflows/My%20Workflow/changelog.md'
+    )
+  })
+
+  it('drops duplicate tool_result events before forwarding them', async () => {
+    const toolResult = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.tool,
+      payload: {
+        toolCallId: 'tool-result-dedupe',
+        toolName: 'search_online',
+        executor: MothershipStreamV1ToolExecutor.sim,
+        mode: MothershipStreamV1ToolMode.async,
+        phase: MothershipStreamV1ToolPhase.result,
+        success: true,
+        output: { value: 'ok' },
+      },
+    })
+    const complete = createEvent({
+      streamId: 'stream-1',
+      cursor: '2',
+      seq: 2,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.complete,
+      payload: {
+        status: MothershipStreamV1CompletionStatus.complete,
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(createSseResponse([toolResult, toolResult, complete]))
+
+    const onEvent = vi.fn()
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      onEvent,
+      timeout: 1000,
+    })
+
+    expect(onEvent.mock.calls.map(([event]) => event.type)).toEqual([
+      MothershipStreamV1EventType.tool,
+      MothershipStreamV1EventType.complete,
+    ])
+    expect(onEvent).toHaveBeenCalledWith(
+      expect.objectContaining({
+        type: MothershipStreamV1EventType.tool,
+        payload: expect.objectContaining({
+          toolCallId: 'tool-result-dedupe',
+          phase: MothershipStreamV1ToolPhase.result,
+        }),
+      })
+    )
+    expect(context.toolCalls.get('tool-result-dedupe')).toEqual(
+      expect.objectContaining({
+        id: 'tool-result-dedupe',
+        name: 'search_online',
+        status: MothershipStreamV1ToolOutcome.success,
+        result: { success: true, output: { value: 'ok' } },
+      })
+    )
+  })
+
+  it('does not retry transient backend statuses because stream requests are not idempotent', async () => {
+    vi.mocked(fetch).mockResolvedValueOnce(new Response('bad gateway', { status: 502 }))
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toMatchObject({
+      name: 'CopilotBackendError',
+      status: 502,
+      body: 'bad gateway',
+    })
+
+    expect(fetch).toHaveBeenCalledTimes(1)
+  })
+
+  it('does not retry non-transient backend statuses before the SSE stream opens', async () => {
+    vi.mocked(fetch).mockResolvedValueOnce(new Response('limit reached', { status: 402 }))
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toThrow('Usage limit reached')
+
+    expect(fetch).toHaveBeenCalledTimes(1)
+  })
+
+  it('does not retry network errors because Go may already be executing the request', async () => {
+    vi.mocked(fetch).mockRejectedValueOnce(new TypeError('fetch failed'))
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toThrow('fetch failed')
+
+    expect(fetch).toHaveBeenCalledTimes(1)
+  })
+
+  it('fails closed when the shared stream ends before a terminal event', async () => {
+    const textEvent = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.text,
+      payload: {
+        channel: 'assistant',
+        text: 'partial response',
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(createSseResponse([textEvent]))
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toThrow('Copilot backend stream ended before a terminal event')
+    expect(
+      context.errors.some((message) =>
+        message.includes('Copilot backend stream ended before a terminal event')
+      )
+    ).toBe(true)
+  })
+
+  it('reclassifies as aborted when the body closes without terminal but the abort marker is set', async () => {
+    const textEvent = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.text,
+      payload: {
+        channel: 'assistant',
+        text: 'partial response',
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(createSseResponse([textEvent]))
+    vi.mocked(hasAbortMarker).mockResolvedValueOnce(true)
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      timeout: 1000,
+    })
+
+    expect(hasAbortMarker).toHaveBeenCalledWith(context.messageId)
+    expect(context.wasAborted).toBe(true)
+    expect(
+      context.errors.some((message) =>
+        message.includes('Copilot backend stream ended before a terminal event')
+      )
+    ).toBe(false)
+  })
+
+  it('invokes onAbortObserved with MarkerObservedAtBodyClose when reclassifying via the abort marker', async () => {
+    const textEvent = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.text,
+      payload: {
+        channel: 'assistant',
+        text: 'partial response',
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(createSseResponse([textEvent]))
+    vi.mocked(hasAbortMarker).mockResolvedValueOnce(true)
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+    const onAbortObserved = vi.fn()
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      timeout: 1000,
+      onAbortObserved,
+    })
+
+    expect(onAbortObserved).toHaveBeenCalledTimes(1)
+    expect(onAbortObserved).toHaveBeenCalledWith(AbortReason.MarkerObservedAtBodyClose)
+    expect(context.wasAborted).toBe(true)
+  })
+
+  it('does not invoke onAbortObserved when no abort marker is present at body close', async () => {
+    const textEvent = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.text,
+      payload: {
+        channel: 'assistant',
+        text: 'partial response',
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(createSseResponse([textEvent]))
+    vi.mocked(hasAbortMarker).mockResolvedValueOnce(false)
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+    const onAbortObserved = vi.fn()
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+        onAbortObserved,
+      })
+    ).rejects.toThrow('Copilot backend stream ended before a terminal event')
+
+    expect(onAbortObserved).not.toHaveBeenCalled()
+  })
+
+  it('still fails closed when the body closes without terminal and the abort marker check throws', async () => {
+    const textEvent = createEvent({
+      streamId: 'stream-1',
+      cursor: '1',
+      seq: 1,
+      requestId: 'req-1',
+      type: MothershipStreamV1EventType.text,
+      payload: {
+        channel: 'assistant',
+        text: 'partial response',
+      },
+    })
+
+    vi.mocked(fetch).mockResolvedValueOnce(createSseResponse([textEvent]))
+    vi.mocked(hasAbortMarker).mockRejectedValueOnce(new Error('redis unavailable'))
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toThrow('Copilot backend stream ended before a terminal event')
+    expect(context.wasAborted).toBe(false)
+  })
+
+  it('fails closed when the shared stream receives an invalid event', async () => {
+    vi.mocked(fetch).mockResolvedValueOnce(
+      createSseResponse([
+        {
+          v: 1,
+          type: MothershipStreamV1EventType.tool,
+          seq: 1,
+          ts: '2026-01-01T00:00:00.000Z',
+          stream: { streamId: 'stream-1', cursor: '1' },
+          payload: {
+            phase: MothershipStreamV1ToolPhase.result,
+          },
+        },
+      ])
+    )
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toThrow('Received invalid stream event on shared path')
+    expect(
+      context.errors.some((message) =>
+        message.includes('Received invalid stream event on shared path')
+      )
+    ).toBe(true)
+  })
+
+  it('fails closed when the shared stream receives malformed JSON', async () => {
+    vi.mocked(fetch).mockResolvedValueOnce(
+      createRawSseResponse('data: {"v":1,"type":"text","payload":\n\n')
+    )
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await expect(
+      runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+        timeout: 1000,
+      })
+    ).rejects.toThrow('Failed to parse SSE event JSON')
+    expect(
+      context.errors.some((message) => message.includes('Failed to parse SSE event JSON'))
+    ).toBe(true)
+  })
+
+  it('records a split canonical request id and go trace id from the stream envelope', async () => {
+    vi.mocked(fetch).mockResolvedValueOnce(
+      createSseResponse([
+        {
+          v: 1,
+          type: MothershipStreamV1EventType.text,
+          seq: 1,
+          ts: '2026-01-01T00:00:00.000Z',
+          stream: { streamId: 'stream-1', cursor: '1' },
+          trace: {
+            requestId: 'sim-request-1',
+            goTraceId: 'go-trace-1',
+          },
+          payload: {
+            channel: 'assistant',
+            text: 'hello',
+          },
+        },
+        createEvent({
+          streamId: 'stream-1',
+          cursor: '2',
+          seq: 2,
+          requestId: 'sim-request-1',
+          type: MothershipStreamV1EventType.complete,
+          payload: {
+            status: MothershipStreamV1CompletionStatus.complete,
+          },
+        }),
+      ])
+    )
+
+    const context = createStreamingContext()
+    context.requestId = 'sim-request-1'
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      timeout: 1000,
+    })
+
+    expect(context.requestId).toBe('sim-request-1')
+    expect(
+      context.trace.build({
+        outcome: RequestTraceV1Outcome.success,
+        simRequestId: 'sim-request-1',
+      }).goTraceId
+    ).toBe('go-trace-1')
+  })
+
+  it('records span identity on the subagent block from the scope', async () => {
+    vi.mocked(fetch).mockResolvedValueOnce(
+      createSseResponse([
+        createEvent({
+          streamId: 'stream-1',
+          cursor: '1',
+          seq: 1,
+          requestId: 'req-1',
+          type: MothershipStreamV1EventType.span,
+          scope: {
+            lane: 'subagent',
+            agentId: 'deploy',
+            parentToolCallId: 'tc-deploy-inner',
+            spanId: 'S2',
+            parentSpanId: 'S1',
+          },
+          payload: {
+            kind: 'subagent',
+            event: 'start',
+            agent: 'deploy',
+            data: { tool_call_id: 'tc-deploy-inner', nested: true },
+          },
+        }),
+        createEvent({
+          streamId: 'stream-1',
+          cursor: '2',
+          seq: 2,
+          requestId: 'req-1',
+          type: MothershipStreamV1EventType.complete,
+          payload: { status: MothershipStreamV1CompletionStatus.complete },
+        }),
+      ])
+    )
+
+    const context = createStreamingContext()
+    const execContext: ExecutionContext = {
+      userId: 'user-1',
+      workflowId: 'workflow-1',
+    }
+
+    await runStreamLoop('https://example.com/mothership/stream', {}, context, execContext, {
+      timeout: 1000,
+    })
+
+    const subagentBlock = context.contentBlocks.find((block) => block.type === 'subagent')
+    expect(subagentBlock).toBeDefined()
+    expect(subagentBlock?.spanId).toBe('S2')
+    expect(subagentBlock?.parentSpanId).toBe('S1')
+    expect(subagentBlock?.parentToolCallId).toBe('tc-deploy-inner')
+  })
+})