test(desktop): cover /btw prompt.btw dispatch and btw.complete

Pin the RPC route (not slash.exec), bare-/btw usage, older-gateway
fallback, and originating-session answer rendering.

Co-authored-by: SsSs <w-kwan@hotmail.com>
Co-authored-by: kokhlo <konstantin.khlopkov93@gmail.com>
Co-authored-by: xxxigm <tuancanhnguyen706@gmail.com>

apps/desktop/src/app/session/hooks/use-message-stream/btw-complete-event.test.tsx

@@ -0,0 +1,66 @@
+import { act, cleanup } from '@testing-library/react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+import type { RpcEvent } from '@/types/hermes'
+
+import { type MessageStreamHarness, renderMessageStream } from './test-harness'
+
+const SID = 'session-1'
+const OTHER_SID = 'session-2'
+
+let stream: MessageStreamHarness
+
+function mountStream() {
+  stream = renderMessageStream(SID)
+}
+
+function emit(type: RpcEvent['type'], payload: RpcEvent['payload'] = {}, sessionId = SID) {
+  act(() => stream.handleEvent({ payload, session_id: sessionId, type }))
+}
+
+function lastMessage(id = SID) {
+  return stream.state(id).messages.at(-1)
+}
+
+describe('btw.complete event', () => {
+  beforeEach(() => {
+    mountStream()
+  })
+
+  afterEach(() => {
+    cleanup()
+    vi.restoreAllMocks()
+  })
+
+  // #99065: prompt.btw delivers the answer here. The slash-worker route
+  // printed it after the stdout capture window closed, so only the ack rendered.
+  it('appends the answer to the originating session as a system message', () => {
+    emit('btw.complete', { task_id: 'btw_ab12cd', question: 'which file was that error in?', text: 'src/main.ts' })
+
+    const message = lastMessage()
+
+    expect(message?.role).toBe('system')
+    expect(message?.id).toBe('btw-complete-btw_ab12cd')
+    expect(stream.text()).toBe('[btw "which file was that error in?" (btw_ab12cd)]\nsrc/main.ts')
+  })
+
+  it('keeps another session untouched when the event targets this one', () => {
+    emit('btw.complete', { task_id: 'btw_1', text: 'for the other chat' }, OTHER_SID)
+
+    expect(lastMessage()).toBeUndefined()
+    expect(stream.text(OTHER_SID)).toBe('[btw (btw_1)]\nfor the other chat')
+  })
+
+  it('omits the question and task-id header bits when the backend omits them', () => {
+    emit('btw.complete', { text: 'the answer' })
+
+    expect(stream.text()).toBe('[btw]\nthe answer')
+  })
+
+  it('drops an empty completion instead of appending a blank line', () => {
+    emit('btw.complete', { task_id: 'btw_1', question: 'q', text: '   ' })
+
+    expect(lastMessage()).toBeUndefined()
+  })
+})
+)

apps/desktop/src/app/session/hooks/use-prompt-actions/index.test.tsx

@@ -1002,6 +1002,99 @@ describe('usePromptActions /compress', () => {
   })
 })
 
+describe('usePromptActions /btw', () => {
+  afterEach(() => {
+    cleanup()
+    vi.restoreAllMocks()
+  })
+
+  // #99065: slash.exec only captured the ack; the answer prints after the
+  // worker's stdout window. prompt.btw + btw.complete is the TUI path.
+  it('routes through prompt.btw (not slash.exec) and renders the start notice', async () => {
+    const seeds: Record<string, unknown>[] = []
+
+    const requestGateway = vi.fn(async (method: string) => {
+      if (method === 'prompt.btw') {
+        return { task_id: 'btw_ab12cd' } as never
+      }
+
+      return {} as never
+    })
+
+    let handle: HarnessHandle | null = null
+    await actRender(
+      <Harness
+        onReady={h => (handle = h)}
+        onSeedState={s => seeds.push(s)}
+        refreshSessions={async () => undefined}
+        requestGateway={requestGateway}
+      />
+    )
+
+    await handle!.submitText('/btw which file was that error in?')
+
+    expect(requestGateway).toHaveBeenCalledWith('prompt.btw', {
+      session_id: RUNTIME_SESSION_ID,
+      text: 'which file was that error in?'
+    })
+    expect(requestGateway).not.toHaveBeenCalledWith('slash.exec', expect.anything())
+    expect(requestGateway).not.toHaveBeenCalledWith('command.dispatch', expect.anything())
+    expect(renderedSeedTexts(seeds).some(text => text.includes('btw_ab12cd'))).toBe(true)
+  })
+
+  it('shows usage when no question is typed', async () => {
+    const seeds: Record<string, unknown>[] = []
+
+    const requestGateway = vi.fn(async () => ({} as never))
+
+    let handle: HarnessHandle | null = null
+    await actRender(
+      <Harness
+        onReady={h => (handle = h)}
+        onSeedState={s => seeds.push(s)}
+        refreshSessions={async () => undefined}
+        requestGateway={requestGateway}
+      />
+    )
+
+    await handle!.submitText('/btw')
+
+    expect(requestGateway).not.toHaveBeenCalled()
+    expect(renderedSeedTexts(seeds).some(text => text.includes('Usage: /btw'))).toBe(true)
+  })
+
+  it('falls back to the slash worker when an older gateway lacks prompt.btw', async () => {
+    const seeds: Record<string, unknown>[] = []
+
+    const requestGateway = vi.fn(async (method: string) => {
+      if (method === 'prompt.btw') {
+        throw new Error('method not found: prompt.btw')
+      }
+
+      if (method === 'slash.exec') {
+        return { output: 'Side question started by legacy gateway' } as never
+      }
+
+      throw new Error(`unexpected method: ${method}`)
+    })
+
+    let handle: HarnessHandle | null = null
+    await actRender(
+      <Harness
+        onReady={h => (handle = h)}
+        onSeedState={s => seeds.push(s)}
+        refreshSessions={async () => undefined}
+        requestGateway={requestGateway}
+      />
+    )
+
+    await handle!.submitText('/btw anything')
+
+    expect(requestGateway).toHaveBeenCalledWith('slash.exec', expect.objectContaining({ command: 'btw anything' }))
+    expect(renderedSeedTexts(seeds).some(text => text.includes('legacy gateway'))).toBe(true)
+  })
+})
+
 describe('usePromptActions exec fallback error reporting', () => {
   beforeEach(() => {
     setSessions(() => [sessionInfo()])

apps/desktop/src/lib/desktop-slash-commands.test.ts

@@ -232,9 +232,9 @@ describe('desktop slash command curation', () => {
   })
 
   it('still routes commands without dedicated RPCs through exec()', () => {
+    // /btw is an action (prompt.btw) — the slash-worker print never reached Desktop.
     const execNames = [
       '/bg',
-      '/btw',
       '/debug',
       '/goal',
       '/personality',
@@ -251,6 +251,13 @@ describe('desktop slash command curation', () => {
     }
   })
 
+  it('routes /btw to the prompt.btw side-question action', () => {
+    expect(resolveDesktopCommand('/btw')?.surface).toEqual({ kind: 'action', action: 'btw' })
+    expect(isDesktopSlashCommand('/btw')).toBe(true)
+    expect(isDesktopSlashSuggestion('/btw')).toBe(true)
+    expect(desktopSlashUnavailableMessage('/btw')).toBeNull()
+  })
+
   it('distinguishes free prose from finite slash option lists', () => {
     expect(desktopSlashCommandArgumentMode('/goal')).toBe('mixed')
     expect(desktopSlashCommandArgumentMode('/steer')).toBe('text')