fix(desktop): handle slash exec dispatch payloads (#49358)

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

@@ -205,6 +205,67 @@ describe('usePromptActions /title', () => {
   })
 })
 
+describe('usePromptActions slash.exec dispatch payloads', () => {
+  afterEach(() => {
+    cleanup()
+    $busy.set(false)
+    vi.restoreAllMocks()
+  })
+
+  it('submits /goal send directives returned directly by slash.exec instead of rendering no output', async () => {
+    const calls: { method: string; params?: Record<string, unknown> }[] = []
+    const states: Record<string, unknown>[] = []
+    const requestGateway = vi.fn(async (method: string, params?: Record<string, unknown>) => {
+      calls.push({ method, params })
+
+      if (method === 'slash.exec') {
+        return {
+          type: 'send',
+          notice: '⊙ Goal set. Starting now.',
+          message: 'write the implementation plan'
+        } as never
+      }
+
+      return {} as never
+    })
+
+    let handle: HarnessHandle | null = null
+    render(
+      <Harness
+        onReady={h => (handle = h)}
+        onSeedState={s => states.push(s)}
+        refreshSessions={async () => undefined}
+        requestGateway={requestGateway}
+      />
+    )
+
+    await handle!.submitText('/goal write the implementation plan')
+
+    expect(calls.map(c => c.method)).toEqual(['slash.exec', 'prompt.submit'])
+    expect(calls[0]?.params).toEqual({
+      command: 'goal write the implementation plan',
+      session_id: RUNTIME_SESSION_ID
+    })
+    expect(calls[1]?.params).toEqual({
+      session_id: RUNTIME_SESSION_ID,
+      text: 'write the implementation plan'
+    })
+
+    const renderedText = states
+      .flatMap(state => {
+        const messages = Array.isArray(state.messages)
+          ? (state.messages as Array<{ parts?: Array<{ text?: string }> }>)
+          : []
+
+        return messages.flatMap(message => (message.parts ?? []).map(part => part.text ?? ''))
+      })
+      .join('\n')
+
+    expect(renderedText).toContain('⊙ Goal set. Starting now.')
+    expect(renderedText).not.toContain('/goal: no output')
+  })
+})
+
 describe('usePromptActions desktop slash pickers', () => {
   beforeEach(() => {
     setSessions(() => [sessionInfo({ id: '20260610_120000_abcdef', title: 'Loaded session' })])

apps/desktop/src/app/session/hooks/use-prompt-actions.ts

@@ -915,31 +915,7 @@ export function usePromptActions({
           return
         }
 
-        try {
-          const result = await requestGateway<SlashExecResponse>('slash.exec', {
-            session_id: sessionId,
-            command: command.replace(/^\/+/, '')
-          })
-
-          const body = result?.output || `/${name}: no output`
-          renderSlashOutput(result?.warning ? `warning: ${result.warning}\n${body}` : body)
-
-          return
-        } catch {
-          // Fall back to command.dispatch for skill/send/alias directives.
-        }
-
-        try {
-          const dispatch = parseCommandDispatch(
-            await requestGateway<unknown>('command.dispatch', { session_id: sessionId, name, arg })
-          )
-
-          if (!dispatch) {
-            renderSlashOutput('error: invalid response: command.dispatch')
-
-            return
-          }
-
+        const handleDispatch = async (dispatch: NonNullable<ReturnType<typeof parseCommandDispatch>>): Promise<void> => {
           if (dispatch.type === 'exec' || dispatch.type === 'plugin') {
             renderSlashOutput(dispatch.output ?? '(no output)')
 
@@ -991,6 +967,43 @@ export function usePromptActions({
           }
 
           await submitPromptText(message)
+        }
+
+        try {
+          const result = await requestGateway<unknown>('slash.exec', {
+            session_id: sessionId,
+            command: command.replace(/^\/+/, '')
+          })
+
+          const dispatch = parseCommandDispatch(result)
+
+          if (dispatch) {
+            await handleDispatch(dispatch)
+
+            return
+          }
+
+          const output = result && typeof result === 'object' ? (result as SlashExecResponse) : null
+          const body = output?.output || `/${name}: no output`
+          renderSlashOutput(output?.warning ? `warning: ${output.warning}\n${body}` : body)
+
+          return
+        } catch {
+          // Fall back to command.dispatch for skill/send/alias directives.
+        }
+
+        try {
+          const dispatch = parseCommandDispatch(
+            await requestGateway<unknown>('command.dispatch', { session_id: sessionId, name, arg })
+          )
+
+          if (!dispatch) {
+            renderSlashOutput('error: invalid response: command.dispatch')
+
+            return
+          }
+
+          await handleDispatch(dispatch)
         } catch (err) {
           renderSlashOutput(`error: ${err instanceof Error ? err.message : String(err)}`)
         }