feat(cli): add cancelled status for interrupted subagents

- Add cancelled status to AgentContentBlock type
- Show ⊘ cancelled indicator in red when user interrupts response
- Mark running subagents as cancelled on abort
- Clear streamingAgents set so cancelled status displays correctly

Author: brandonkachen

cli/src/hooks/helpers/__tests__/send-message.test.ts

@@ -101,6 +101,7 @@ describe('setupStreamingContext', () => {
         setIsRetrying: (value: boolean) => {
           isRetrying = value
         },
+        setStreamingAgents: () => {},
       })
 
       // Trigger abort
@@ -163,6 +164,7 @@ describe('setupStreamingContext', () => {
         isQueuePausedRef,
         updateChainInProgress: () => {},
         setIsRetrying: () => {},
+        setStreamingAgents: () => {},
       })
 
       // Trigger abort
@@ -192,6 +194,7 @@ describe('setupStreamingContext', () => {
         isProcessingQueueRef,
         updateChainInProgress: () => {},
         setIsRetrying: () => {},
+        setStreamingAgents: () => {},
       })
 
       // Verify ref starts as true
@@ -238,6 +241,7 @@ describe('setupStreamingContext', () => {
         setIsRetrying: (value) => {
           isRetrying = value
         },
+        setStreamingAgents: () => {},
       })
 
       // Sanity check initial state
@@ -278,6 +282,7 @@ describe('setupStreamingContext', () => {
         setCanProcessQueue: () => {},
         updateChainInProgress: () => {},
         setIsRetrying: () => {},
+        setStreamingAgents: () => {},
       })
 
       // Verify abortController is stored in ref
@@ -306,6 +311,7 @@ describe('setupStreamingContext', () => {
         setCanProcessQueue: () => {},
         updateChainInProgress: () => {},
         setIsRetrying: () => {},
+        setStreamingAgents: () => {},
       })
 
       // Verify streamRefs was reset

cli/src/hooks/helpers/send-message.ts

@@ -7,6 +7,7 @@ import {
 } from '../../utils/error-handling'
 import { invalidateActivityQuery } from '../use-activity-query'
 import { usageQueryKeys } from '../use-usage-query'
+import { markRunningAgentsAsCancelled } from '../../utils/block-operations'
 import { formatElapsedTime } from '../../utils/format-elapsed-time'
 import { processImagesForMessage } from '../../utils/image-processor'
 import { logger } from '../../utils/logger'
@@ -192,6 +193,7 @@ export const setupStreamingContext = (params: {
   isProcessingQueueRef?: MutableRefObject<boolean>
   updateChainInProgress: (value: boolean) => void
   setIsRetrying: (value: boolean) => void
+  setStreamingAgents: (updater: (prev: Set<string>) => Set<string>) => void
 }) => {
   const {
     aiMessageId,
@@ -205,6 +207,7 @@ export const setupStreamingContext = (params: {
     isProcessingQueueRef,
     updateChainInProgress,
     setIsRetrying,
+    setStreamingAgents,
   } = params
 
   streamRefs.reset()
@@ -229,7 +232,13 @@ export const setupStreamingContext = (params: {
     setIsRetrying(false)
     timerController.stop('aborted')
 
-    updater.updateAiMessageBlocks((blocks) => appendInterruptionNotice(blocks))
+    // Clear streaming agents so cancelled status displays correctly in UI
+    setStreamingAgents(() => new Set())
+
+    updater.updateAiMessageBlocks((blocks) => {
+      const cancelledBlocks = markRunningAgentsAsCancelled(blocks)
+      return appendInterruptionNotice(cancelledBlocks)
+    })
     updater.markComplete()
   })
 

cli/src/hooks/use-send-message.ts

@@ -343,6 +343,7 @@ export const useSendMessage = ({
           isProcessingQueueRef,
           updateChainInProgress,
           setIsRetrying,
+          setStreamingAgents,
         })
       setStreamStatus('waiting')
       setMessages((prev) => [...prev, aiMessage])

cli/src/types/chat.ts

@@ -49,7 +49,7 @@ export type AgentContentBlock = {
   agentName: string
   agentType: string
   content: string
-  status: 'running' | 'complete' | 'failed'
+  status: 'running' | 'complete' | 'failed' | 'cancelled'
   blocks?: ContentBlock[]
   initialPrompt?: string
   params?: Record<string, any>

cli/src/utils/agent-helpers.ts

@@ -19,6 +19,8 @@ export function getAgentStatusInfo(
       return { indicator: '✗', label: 'failed', color: 'red', text: '✗ failed' }
     case 'complete':
       return { indicator: '✓', label: 'completed', color: theme.foreground, text: 'completed ✓' }
+    case 'cancelled':
+      return { indicator: '⊘', label: 'cancelled', color: 'red', text: '⊘ cancelled' }
     default:
       return { indicator: '○', label: 'waiting', color: theme.muted, text: '○ waiting' }
   }

cli/src/utils/block-operations.ts

@@ -355,3 +355,35 @@ export const markAgentComplete = (blocks: ContentBlock[], agentId: string) =>
     }
     return { ...block, status: 'complete' as const }
   })
+
+/**
+ * Recursively marks all agent blocks with status 'running' as 'cancelled'.
+ * Used when the user interrupts a response to indicate subagents were stopped.
+ */
+export const markRunningAgentsAsCancelled = (
+  blocks: ContentBlock[],
+): ContentBlock[] => {
+  return blocks.map((block) => {
+    if (block.type !== 'agent') {
+      return block
+    }
+
+    const updatedBlocks = block.blocks
+      ? markRunningAgentsAsCancelled(block.blocks)
+      : undefined
+
+    if (block.status === 'running') {
+      return {
+        ...block,
+        status: 'cancelled' as const,
+        ...(updatedBlocks && { blocks: updatedBlocks }),
+      }
+    }
+
+    if (updatedBlocks && updatedBlocks !== block.blocks) {
+      return { ...block, blocks: updatedBlocks }
+    }
+
+    return block
+  })
+}