feat(core): integrate remote agents with ExecutionLifecycleService for backgrounding

Wire RemoteAgentInvocation to use ExecutionLifecycleService.createExecution()
so remote agents can be backgrounded (Ctrl+B), subscribed to, and killed
through the same lifecycle system as shell commands.

- Create virtual execution on execute(), report ID via setExecutionIdCallback
- Stream output deltas via appendOutput() so lifecycle subscribers see live data
- Separate streaming into detached processStream() that settles the lifecycle
- Support backgrounding: handle.result resolves with backgrounded=true,
  stream continues running, returns BackgroundExecutionData
- Support kill: lifecycle onKill aborts the stream via AbortController

packages/cli/src/ui/AppContainer.tsx

@@ -83,6 +83,7 @@ import {
   ProjectIdRequiredError,
   CoreToolCallStatus,
   buildUserSteeringHintPrompt,
+  formatBackgroundCompletionForModel,
   logBillingEvent,
   ApiKeyUpdatedEvent,
   type InjectionSource,
@@ -1078,6 +1079,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
 
   const pendingHintsRef = useRef<string[]>([]);
   const [pendingHintCount, setPendingHintCount] = useState(0);
+  const pendingBgCompletionsRef = useRef<string[]>([]);
+  const [pendingBgCompletionCount, setPendingBgCompletionCount] = useState(0);
 
   const consumePendingHints = useCallback(() => {
     if (pendingHintsRef.current.length === 0) {
@@ -1090,16 +1093,18 @@ Logging in with Google... Restarting Gemini CLI to continue.
   }, []);
 
   useEffect(() => {
-    const hintListener = (text: string, source: InjectionSource) => {
-      if (source !== 'user_steering') {
-        return;
+    const injectionListener = (text: string, source: InjectionSource) => {
+      if (source === 'user_steering') {
+        pendingHintsRef.current.push(text);
+        setPendingHintCount((prev) => prev + 1);
+      } else if (source === 'background_completion') {
+        pendingBgCompletionsRef.current.push(text);
+        setPendingBgCompletionCount((prev) => prev + 1);
       }
-      pendingHintsRef.current.push(text);
-      setPendingHintCount((prev) => prev + 1);
     };
-    config.injectionService.onInjection(hintListener);
+    config.injectionService.onInjection(injectionListener);
     return () => {
-      config.injectionService.offInjection(hintListener);
+      config.injectionService.offInjection(injectionListener);
     };
   }, [config]);
 
@@ -2135,6 +2140,29 @@ Logging in with Google... Restarting Gemini CLI to continue.
     pendingHintCount,
   ]);
 
+  useEffect(() => {
+    if (
+      !isConfigInitialized ||
+      streamingState !== StreamingState.Idle ||
+      !isMcpReady ||
+      pendingBgCompletionsRef.current.length === 0
+    ) {
+      return;
+    }
+
+    const bgText = pendingBgCompletionsRef.current.join('\n');
+    pendingBgCompletionsRef.current = [];
+    setPendingBgCompletionCount(0);
+
+    void submitQuery([{ text: formatBackgroundCompletionForModel(bgText) }]);
+  }, [
+    isConfigInitialized,
+    isMcpReady,
+    streamingState,
+    submitQuery,
+    pendingBgCompletionCount,
+  ]);
+
   const allToolCalls = useMemo(
     () =>
       pendingHistoryItems

packages/cli/src/ui/hooks/shellCommandProcessor.test.tsx

@@ -35,6 +35,23 @@ const mockShellOnExit = vi.hoisted(() =>
     ) => () => void
   >(() => vi.fn()),
 );
+const mockLifecycleSubscribe = vi.hoisted(() =>
+  vi.fn<
+    (pid: number, listener: (event: ShellOutputEvent) => void) => () => void
+  >(() => vi.fn()),
+);
+const mockLifecycleOnExit = vi.hoisted(() =>
+  vi.fn<
+    (
+      pid: number,
+      callback: (exitCode: number, signal?: number) => void,
+    ) => () => void
+  >(() => vi.fn()),
+);
+const mockLifecycleKill = vi.hoisted(() => vi.fn());
+const mockLifecycleBackground = vi.hoisted(() => vi.fn());
+const mockLifecycleOnBackground = vi.hoisted(() => vi.fn());
+const mockLifecycleOffBackground = vi.hoisted(() => vi.fn());
 
 vi.mock('@google/gemini-cli-core', async (importOriginal) => {
   const actual =
@@ -48,6 +65,14 @@ vi.mock('@google/gemini-cli-core', async (importOriginal) => {
       subscribe: mockShellSubscribe,
       onExit: mockShellOnExit,
     },
+    ExecutionLifecycleService: {
+      subscribe: mockLifecycleSubscribe,
+      onExit: mockLifecycleOnExit,
+      kill: mockLifecycleKill,
+      background: mockLifecycleBackground,
+      onBackground: mockLifecycleOnBackground,
+      offBackground: mockLifecycleOffBackground,
+    },
     isBinary: mockIsBinary,
   };
 });
@@ -784,8 +809,11 @@ describe('useShellCommandProcessor', () => {
           output: 'initial',
         }),
       );
-      expect(mockShellOnExit).toHaveBeenCalledWith(1001, expect.any(Function));
-      expect(mockShellSubscribe).toHaveBeenCalledWith(
+      expect(mockLifecycleOnExit).toHaveBeenCalledWith(
+        1001,
+        expect.any(Function),
+      );
+      expect(mockLifecycleSubscribe).toHaveBeenCalledWith(
         1001,
         expect.any(Function),
       );
@@ -823,7 +851,7 @@ describe('useShellCommandProcessor', () => {
       expect(addItemToHistoryMock).toHaveBeenCalledWith(
         expect.objectContaining({
           type: 'info',
-          text: 'No background shells are currently active.',
+          text: 'No background tasks are currently active.',
         }),
         expect.any(Number),
       );
@@ -841,7 +869,7 @@ describe('useShellCommandProcessor', () => {
         await result.current.dismissBackgroundShell(1001);
       });
 
-      expect(mockShellKill).toHaveBeenCalledWith(1001);
+      expect(mockLifecycleKill).toHaveBeenCalledWith(1001);
       expect(result.current.backgroundShellCount).toBe(0);
       expect(result.current.backgroundShells.has(1001)).toBe(false);
     });
@@ -891,7 +919,7 @@ describe('useShellCommandProcessor', () => {
       expect(result.current.activeShellPtyId).toBeNull();
     });
 
-    it('should persist background shell on successful exit and mark as exited', async () => {
+    it('should auto-dismiss background task on successful exit', async () => {
       const { result } = renderProcessorHook();
 
       act(() => {
@@ -899,7 +927,7 @@ describe('useShellCommandProcessor', () => {
       });
 
       // Find the exit callback registered
-      const exitCallback = mockShellOnExit.mock.calls.find(
+      const exitCallback = mockLifecycleOnExit.mock.calls.find(
         (call) => call[0] === 888,
       )?.[1];
       expect(exitCallback).toBeDefined();
@@ -910,22 +938,19 @@ describe('useShellCommandProcessor', () => {
         });
       }
 
-      // Should NOT be removed, but updated
-      expect(result.current.backgroundShellCount).toBe(0); // Badge count is 0
-      expect(result.current.backgroundShells.has(888)).toBe(true); // Map has it
-      const shell = result.current.backgroundShells.get(888);
-      expect(shell?.status).toBe('exited');
-      expect(shell?.exitCode).toBe(0);
+      // Should be auto-dismissed from the panel
+      expect(result.current.backgroundShellCount).toBe(0);
+      expect(result.current.backgroundShells.has(888)).toBe(false);
     });
 
-    it('should persist background shell on failed exit', async () => {
+    it('should auto-dismiss background task on failed exit', async () => {
       const { result } = renderProcessorHook();
 
       act(() => {
         result.current.registerBackgroundShell(999, 'fail-exit', '');
       });
 
-      const exitCallback = mockShellOnExit.mock.calls.find(
+      const exitCallback = mockLifecycleOnExit.mock.calls.find(
         (call) => call[0] === 999,
       )?.[1];
       expect(exitCallback).toBeDefined();
@@ -936,17 +961,9 @@ describe('useShellCommandProcessor', () => {
         });
       }
 
-      // Should NOT be removed, but updated
-      expect(result.current.backgroundShellCount).toBe(0); // Badge count is 0
-      const shell = result.current.backgroundShells.get(999);
-      expect(shell?.status).toBe('exited');
-      expect(shell?.exitCode).toBe(1);
-
-      // Now dismiss it
-      await act(async () => {
-        await result.current.dismissBackgroundShell(999);
-      });
+      // Should be auto-dismissed from the panel
       expect(result.current.backgroundShellCount).toBe(0);
+      expect(result.current.backgroundShells.has(999)).toBe(false);
     });
 
     it('should NOT trigger re-render on background shell output when visible', async () => {
@@ -963,7 +980,7 @@ describe('useShellCommandProcessor', () => {
 
       const initialRenderCount = getRenderCount();
 
-      const subscribeCallback = mockShellSubscribe.mock.calls.find(
+      const subscribeCallback = mockLifecycleSubscribe.mock.calls.find(
         (call) => call[0] === 1001,
       )?.[1];
       expect(subscribeCallback).toBeDefined();
@@ -989,7 +1006,7 @@ describe('useShellCommandProcessor', () => {
       // Ensure background shells are hidden (default)
       const initialRenderCount = getRenderCount();
 
-      const subscribeCallback = mockShellSubscribe.mock.calls.find(
+      const subscribeCallback = mockLifecycleSubscribe.mock.calls.find(
         (call) => call[0] === 1001,
       )?.[1];
       expect(subscribeCallback).toBeDefined();
@@ -1019,7 +1036,7 @@ describe('useShellCommandProcessor', () => {
 
       const initialRenderCount = getRenderCount();
 
-      const subscribeCallback = mockShellSubscribe.mock.calls.find(
+      const subscribeCallback = mockLifecycleSubscribe.mock.calls.find(
         (call) => call[0] === 1001,
       )?.[1];
       expect(subscribeCallback).toBeDefined();

packages/cli/src/ui/hooks/shellCommandProcessor.ts

@@ -9,10 +9,16 @@ import type {
   IndividualToolCallDisplay,
 } from '../types.js';
 import { useCallback, useReducer, useRef, useEffect } from 'react';
-import type { AnsiOutput, Config, GeminiClient } from '@google/gemini-cli-core';
+import type {
+  AnsiOutput,
+  Config,
+  GeminiClient,
+  CompletionBehavior,
+} from '@google/gemini-cli-core';
 import {
   isBinary,
   ShellExecutionService,
+  ExecutionLifecycleService,
   CoreToolCallStatus,
 } from '@google/gemini-cli-core';
 import { type PartListUnion } from '@google/genai';
@@ -144,7 +150,7 @@ export const useShellCommandProcessor = (
 
   useEffect(
     () => () => {
-      // Unsubscribe from all background shell events on unmount
+      // Unsubscribe from all background task events on unmount
       for (const unsubscribe of m.subscriptions.values()) {
         unsubscribe();
       }
@@ -176,7 +182,7 @@ export const useShellCommandProcessor = (
       addItemToHistory(
         {
           type: 'info',
-          text: 'No background shells are currently active.',
+          text: 'No background tasks are currently active.',
         },
         Date.now(),
       );
@@ -191,12 +197,19 @@ export const useShellCommandProcessor = (
     dispatch,
   ]);
 
-  const backgroundCurrentShell = useCallback(() => {
+  const backgroundCurrentExecution = useCallback(() => {
     const pidToBackground =
       state.activeShellPtyId ?? activeBackgroundExecutionId;
     if (pidToBackground) {
-      ShellExecutionService.background(pidToBackground);
-      m.backgroundedPids.add(pidToBackground);
+      // Use ShellExecutionService for shell PTYs (handles log files, etc.),
+      // fall back to ExecutionLifecycleService for non-shell executions
+      // (e.g. remote agents, MCP tools, local agents).
+      if (state.activeShellPtyId) {
+        m.backgroundedPids.add(pidToBackground);
+        ShellExecutionService.background(pidToBackground);
+      } else {
+        ExecutionLifecycleService.background(pidToBackground);
+      }
       // Ensure backgrounding is silent and doesn't trigger restoration
       m.wasVisibleBeforeForeground = false;
       if (m.restoreTimeout) {
@@ -206,12 +219,14 @@ export const useShellCommandProcessor = (
     }
   }, [state.activeShellPtyId, activeBackgroundExecutionId, m]);
 
-  const dismissBackgroundShell = useCallback(
+  const dismissBackgroundTask = useCallback(
     async (pid: number) => {
       const shell = state.backgroundShells.get(pid);
       if (shell) {
         if (shell.status === 'running') {
-          await ShellExecutionService.kill(pid);
+          // ExecutionLifecycleService.kill handles both shell and non-shell
+          // executions. For shells, ShellExecutionService.kill delegates to it.
+          ExecutionLifecycleService.kill(pid);
         }
         dispatch({ type: 'DISMISS_SHELL', pid });
         m.backgroundedPids.delete(pid);
@@ -227,37 +242,69 @@ export const useShellCommandProcessor = (
     [state.backgroundShells, dispatch, m],
   );
 
-  const registerBackgroundShell = useCallback(
-    (pid: number, command: string, initialOutput: string | AnsiOutput) => {
-      dispatch({ type: 'REGISTER_SHELL', pid, command, initialOutput });
+  const registerBackgroundTask = useCallback(
+    (
+      pid: number,
+      command: string,
+      initialOutput: string | AnsiOutput,
+      completionBehavior?: CompletionBehavior,
+    ) => {
+      dispatch({
+        type: 'REGISTER_SHELL',
+        pid,
+        command,
+        initialOutput,
+        completionBehavior,
+      });
 
-      // Subscribe to process exit directly
-      const exitUnsubscribe = ShellExecutionService.onExit(pid, (code) => {
+      // Subscribe to exit via ExecutionLifecycleService (works for all execution types)
+      const exitUnsubscribe = ExecutionLifecycleService.onExit(pid, (code) => {
         dispatch({
           type: 'UPDATE_SHELL',
           pid,
           update: { status: 'exited', exitCode: code },
         });
+        // Auto-dismiss for inject/notify (output was delivered to conversation).
+        // Silent tasks stay in the UI until manually dismissed.
+        if (completionBehavior !== 'silent') {
+          dispatch({ type: 'DISMISS_SHELL', pid });
+        }
+        const unsub = m.subscriptions.get(pid);
+        if (unsub) {
+          unsub();
+          m.subscriptions.delete(pid);
+        }
         m.backgroundedPids.delete(pid);
       });
 
-      // Subscribe to future updates (data only)
-      const dataUnsubscribe = ShellExecutionService.subscribe(pid, (event) => {
-        if (event.type === 'data') {
-          dispatch({ type: 'APPEND_SHELL_OUTPUT', pid, chunk: event.chunk });
-        } else if (event.type === 'binary_detected') {
-          dispatch({ type: 'UPDATE_SHELL', pid, update: { isBinary: true } });
-        } else if (event.type === 'binary_progress') {
-          dispatch({
-            type: 'UPDATE_SHELL',
-            pid,
-            update: {
-              isBinary: true,
-              binaryBytesReceived: event.bytesReceived,
-            },
-          });
-        }
-      });
+      // Subscribe to output via ExecutionLifecycleService (works for all execution types)
+      const dataUnsubscribe = ExecutionLifecycleService.subscribe(
+        pid,
+        (event) => {
+          if (event.type === 'data') {
+            dispatch({
+              type: 'APPEND_SHELL_OUTPUT',
+              pid,
+              chunk: event.chunk,
+            });
+          } else if (event.type === 'binary_detected') {
+            dispatch({
+              type: 'UPDATE_SHELL',
+              pid,
+              update: { isBinary: true },
+            });
+          } else if (event.type === 'binary_progress') {
+            dispatch({
+              type: 'UPDATE_SHELL',
+              pid,
+              update: {
+                isBinary: true,
+                binaryBytesReceived: event.bytesReceived,
+              },
+            });
+          }
+        },
+      );
 
       m.subscriptions.set(pid, () => {
         exitUnsubscribe();
@@ -267,6 +314,34 @@ export const useShellCommandProcessor = (
     [dispatch, m],
   );
 
+  // Auto-register any execution that gets backgrounded, regardless of type.
+  // This is the agnostic hook: any tool that calls
+  // ExecutionLifecycleService.createExecution() or attachExecution()
+  // automatically gets Ctrl+B support — no UI changes needed per tool.
+  useEffect(() => {
+    const listener = (info: {
+      executionId: number;
+      label: string;
+      output: string;
+      completionBehavior: CompletionBehavior;
+    }) => {
+      // Skip if already registered (e.g. shells register via their own flow)
+      if (m.backgroundedPids.has(info.executionId)) {
+        return;
+      }
+      registerBackgroundTask(
+        info.executionId,
+        info.label,
+        info.output,
+        info.completionBehavior,
+      );
+    };
+    ExecutionLifecycleService.onBackground(listener);
+    return () => {
+      ExecutionLifecycleService.offBackground(listener);
+    };
+  }, [registerBackgroundTask, m]);
+
   const handleShellCommand = useCallback(
     (rawQuery: PartListUnion, abortSignal: AbortSignal): boolean => {
       if (typeof rawQuery !== 'string' || rawQuery.trim() === '') {
@@ -439,7 +514,12 @@ export const useShellCommandProcessor = (
           setPendingHistoryItem(null);
 
           if (result.backgrounded && result.pid) {
-            registerBackgroundShell(result.pid, rawQuery, cumulativeStdout);
+            registerBackgroundTask(
+              result.pid,
+              rawQuery,
+              cumulativeStdout,
+              'notify',
+            );
             dispatch({ type: 'SET_ACTIVE_PTY', pid: null });
           }
 
@@ -531,7 +611,7 @@ export const useShellCommandProcessor = (
       setShellInputFocused,
       terminalHeight,
       terminalWidth,
-      registerBackgroundShell,
+      registerBackgroundTask,
       m,
       dispatch,
     ],
@@ -548,9 +628,9 @@ export const useShellCommandProcessor = (
     backgroundShellCount,
     isBackgroundShellVisible: state.isBackgroundShellVisible,
     toggleBackgroundShell,
-    backgroundCurrentShell,
-    registerBackgroundShell,
-    dismissBackgroundShell,
+    backgroundCurrentShell: backgroundCurrentExecution,
+    registerBackgroundShell: registerBackgroundTask,
+    dismissBackgroundShell: dismissBackgroundTask,
     backgroundShells: state.backgroundShells,
   };
 };

packages/cli/src/ui/hooks/shellReducer.ts

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import type { AnsiOutput } from '@google/gemini-cli-core';
+import type { AnsiOutput, CompletionBehavior } from '@google/gemini-cli-core';
 
 export interface BackgroundShell {
   pid: number;
@@ -14,6 +14,7 @@ export interface BackgroundShell {
   binaryBytesReceived: number;
   status: 'running' | 'exited';
   exitCode?: number;
+  completionBehavior?: CompletionBehavior;
 }
 
 export interface ShellState {
@@ -33,6 +34,7 @@ export type ShellAction =
       pid: number;
       command: string;
       initialOutput: string | AnsiOutput;
+      completionBehavior?: CompletionBehavior;
     }
   | { type: 'UPDATE_SHELL'; pid: number; update: Partial<BackgroundShell> }
   | { type: 'APPEND_SHELL_OUTPUT'; pid: number; chunk: string | AnsiOutput }
@@ -72,6 +74,7 @@ export function shellReducer(
         isBinary: false,
         binaryBytesReceived: 0,
         status: 'running',
+        completionBehavior: action.completionBehavior,
       });
       return { ...state, backgroundShells: nextShells };
     }

packages/core/src/agents/remote-invocation.test.ts

@@ -22,6 +22,7 @@ import type { RemoteAgentDefinition } from './types.js';
 import { createMockMessageBus } from '../test-utils/mock-message-bus.js';
 import { A2AAuthProviderFactory } from './auth-provider/factory.js';
 import type { A2AAuthProvider } from './auth-provider/types.js';
+import { ExecutionLifecycleService } from '../services/executionLifecycleService.js';
 
 // Mock A2AClientManager
 vi.mock('./a2a-client-manager.js', () => ({
@@ -58,6 +59,7 @@ describe('RemoteAgentInvocation', () => {
 
   beforeEach(() => {
     vi.clearAllMocks();
+    ExecutionLifecycleService.resetForTest();
     (A2AClientManager.getInstance as Mock).mockReturnValue(mockClientManager);
     (
       RemoteAgentInvocation as unknown as {
@@ -587,6 +589,264 @@ describe('RemoteAgentInvocation', () => {
     });
   });
 
+  describe('Lifecycle Integration', () => {
+    it('should call setExecutionIdCallback with lifecycle execution ID', async () => {
+      mockClientManager.getClient.mockReturnValue({});
+      mockClientManager.sendMessageStream.mockImplementation(
+        async function* () {
+          yield {
+            kind: 'message',
+            messageId: 'msg-1',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Response' }],
+          };
+        },
+      );
+
+      const callback = vi.fn();
+      const invocation = new RemoteAgentInvocation(
+        mockDefinition,
+        { query: 'hi' },
+        mockMessageBus,
+      );
+      await invocation.execute(
+        new AbortController().signal,
+        undefined,
+        undefined,
+        callback,
+      );
+
+      expect(callback).toHaveBeenCalledExactlyOnceWith(expect.any(Number));
+    });
+
+    it('should feed output deltas to lifecycle service subscribers', async () => {
+      mockClientManager.getClient.mockReturnValue({});
+      mockClientManager.sendMessageStream.mockImplementation(
+        async function* () {
+          yield {
+            kind: 'message',
+            messageId: 'msg-1',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Hello' }],
+          };
+          yield {
+            kind: 'message',
+            messageId: 'msg-1',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Hello World' }],
+          };
+        },
+      );
+
+      const receivedChunks: string[] = [];
+      const invocation = new RemoteAgentInvocation(
+        mockDefinition,
+        { query: 'hi' },
+        mockMessageBus,
+      );
+
+      await invocation.execute(
+        new AbortController().signal,
+        undefined,
+        undefined,
+        (id) => {
+          // Subscribe immediately when we get the execution ID
+          ExecutionLifecycleService.subscribe(id, (event) => {
+            if (event.type === 'data' && typeof event.chunk === 'string') {
+              receivedChunks.push(event.chunk);
+            }
+          });
+        },
+      );
+
+      // Lifecycle subscribers should have received output deltas
+      expect(receivedChunks.length).toBeGreaterThan(0);
+      expect(receivedChunks.join('')).toContain('Hello');
+      expect(receivedChunks.join('')).toContain('World');
+    });
+
+    it('should support backgrounding via lifecycle service (Ctrl+B)', async () => {
+      mockClientManager.getClient.mockReturnValue({});
+
+      // Create a controllable stream that blocks between chunks
+      let resolveStream!: () => void;
+      const streamBlocked = new Promise<void>((r) => {
+        resolveStream = r;
+      });
+
+      mockClientManager.sendMessageStream.mockImplementation(
+        async function* () {
+          yield {
+            kind: 'message',
+            messageId: 'msg-1',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Working...' }],
+          };
+          await streamBlocked;
+          yield {
+            kind: 'message',
+            messageId: 'msg-2',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Done' }],
+          };
+        },
+      );
+
+      let capturedId: number | undefined;
+      const invocation = new RemoteAgentInvocation(
+        mockDefinition,
+        { query: 'hi' },
+        mockMessageBus,
+      );
+
+      // Start execution (don't await — we need to background mid-stream)
+      const resultPromise = invocation.execute(
+        new AbortController().signal,
+        undefined,
+        undefined,
+        (id) => {
+          capturedId = id;
+        },
+      );
+
+      // setExecutionIdCallback is called synchronously before first await
+      expect(capturedId).toBeDefined();
+
+      // Flush microtasks so processStream processes the first chunk
+      await new Promise((resolve) => setTimeout(resolve, 0));
+
+      // Background the execution (simulates Ctrl+B)
+      ExecutionLifecycleService.background(capturedId!);
+
+      const result = await resultPromise;
+
+      // Should return backgrounded result with execution data
+      expect(result.data).toBeDefined();
+      expect((result.data as Record<string, unknown>)['pid']).toBe(capturedId);
+      expect(result.returnDisplay).toContain('background');
+      expect((result.llmContent as Array<{ text: string }>)[0].text).toContain(
+        'background',
+      );
+
+      // Let the stream finish cleanly in the background
+      resolveStream();
+      await new Promise((resolve) => setTimeout(resolve, 0));
+    });
+
+    it('should abort stream when killed via lifecycle service', async () => {
+      mockClientManager.getClient.mockReturnValue({});
+
+      let resolveStream!: () => void;
+      const streamBlocked = new Promise<void>((r) => {
+        resolveStream = r;
+      });
+
+      mockClientManager.sendMessageStream.mockImplementation(
+        async function* () {
+          yield {
+            kind: 'message',
+            messageId: 'msg-1',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Working...' }],
+          };
+          await streamBlocked;
+          yield {
+            kind: 'message',
+            messageId: 'msg-2',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Should not reach' }],
+          };
+        },
+      );
+
+      let capturedId: number | undefined;
+      const invocation = new RemoteAgentInvocation(
+        mockDefinition,
+        { query: 'hi' },
+        mockMessageBus,
+      );
+      const resultPromise = invocation.execute(
+        new AbortController().signal,
+        undefined,
+        undefined,
+        (id) => {
+          capturedId = id;
+        },
+      );
+
+      // Flush microtasks so processStream processes first chunk
+      await new Promise((resolve) => setTimeout(resolve, 0));
+
+      // Kill via lifecycle service
+      ExecutionLifecycleService.kill(capturedId!);
+
+      // Unblock stream so processStream can finish cleanup
+      resolveStream();
+
+      const result = await resultPromise;
+
+      // Kill produces an error result
+      expect(result.error).toBeDefined();
+      expect(result.error?.message).toContain('cancelled');
+
+      // Give processStream time to finish cleanup
+      await new Promise((resolve) => setTimeout(resolve, 0));
+    });
+
+    it('should report execution as active while stream is running', async () => {
+      mockClientManager.getClient.mockReturnValue({});
+
+      let resolveStream!: () => void;
+      const streamBlocked = new Promise<void>((r) => {
+        resolveStream = r;
+      });
+
+      mockClientManager.sendMessageStream.mockImplementation(
+        async function* () {
+          yield {
+            kind: 'message',
+            messageId: 'msg-1',
+            role: 'agent',
+            parts: [{ kind: 'text', text: 'Running' }],
+          };
+          await streamBlocked;
+        },
+      );
+
+      let capturedId: number | undefined;
+      const invocation = new RemoteAgentInvocation(
+        mockDefinition,
+        { query: 'hi' },
+        mockMessageBus,
+      );
+      const resultPromise = invocation.execute(
+        new AbortController().signal,
+        undefined,
+        undefined,
+        (id) => {
+          capturedId = id;
+        },
+      );
+
+      await new Promise((resolve) => setTimeout(resolve, 0));
+
+      // While stream is running, execution should be active
+      expect(ExecutionLifecycleService.isActive(capturedId!)).toBe(true);
+
+      // Complete the stream
+      resolveStream();
+      // Wait for processStream to complete — it calls completeExecution
+      // which emits 'exit' and cleans up. Need to let the for-await-of
+      // loop process the generator's {done: true} and the catch/finally
+      // blocks to run. Multiple microtask ticks may be needed.
+      await new Promise((resolve) => setTimeout(resolve, 0));
+      await resultPromise;
+
+      // After completion, execution should no longer be active
+      expect(ExecutionLifecycleService.isActive(capturedId!)).toBe(false);
+    });
+  });
+
   describe('Confirmations', () => {
     it('should return info confirmation details', async () => {
       const invocation = new RemoteAgentInvocation(

packages/core/src/agents/remote-invocation.ts

@@ -9,6 +9,7 @@ import {
   type ToolConfirmationOutcome,
   type ToolResult,
   type ToolCallConfirmationDetails,
+  type BackgroundExecutionData,
 } from '../tools/tools.js';
 import {
   DEFAULT_QUERY_STRING,
@@ -28,6 +29,8 @@ import { safeJsonToMarkdown } from '../utils/markdownUtils.js';
 import type { AnsiOutput } from '../utils/terminalSerializer.js';
 import { A2AAuthProviderFactory } from './auth-provider/factory.js';
 import { A2AAgentError } from './a2a-errors.js';
+import { ExecutionLifecycleService } from '../services/executionLifecycleService.js';
+import type { ShellExecutionConfig } from '../services/shellExecutionService.js';
 
 /**
  * A tool invocation that proxies to a remote A2A agent.
@@ -116,13 +119,115 @@ export class RemoteAgentInvocation extends BaseToolInvocation<
   }
 
   async execute(
-    _signal: AbortSignal,
+    signal: AbortSignal,
     updateOutput?: (output: string | AnsiOutput) => void,
+    _shellExecutionConfig?: ShellExecutionConfig,
+    setExecutionIdCallback?: (executionId: number) => void,
   ): Promise<ToolResult> {
-    // 1. Ensure the agent is loaded (cached by manager)
-    // We assume the user has provided an access token via some mechanism (TODO),
-    // or we rely on ADC.
+    // Create an AbortController for lifecycle kill support.
+    // Parent abort and lifecycle kill both funnel through this controller.
+    const executionAbortController = new AbortController();
+    if (signal.aborted) {
+      executionAbortController.abort();
+    } else {
+      signal.addEventListener('abort', () => executionAbortController.abort(), {
+        once: true,
+      });
+    }
+
+    // Register with lifecycle service as a virtual execution so this
+    // invocation can be backgrounded, subscribed to, and killed.
+    const handle = ExecutionLifecycleService.createExecution(
+      '',
+      () => executionAbortController.abort(),
+      'remote_agent',
+    );
+    // createExecution always produces a valid numeric ID
+    const executionId = handle.pid!;
+
+    if (setExecutionIdCallback) {
+      setExecutionIdCallback(executionId);
+    }
+
+    // Guard: stop calling updateOutput after backgrounding since the
+    // tool call has already returned from the scheduler's perspective.
+    let backgrounded = false;
+
+    // Fire-and-forget: stream processing runs concurrently and settles the
+    // lifecycle execution on completion or error.
+    const streamingPromise = this.processStream(
+      executionId,
+      executionAbortController.signal,
+      (output) => {
+        if (!backgrounded && updateOutput) {
+          updateOutput(output);
+        }
+      },
+    );
+    // Errors are handled internally via completeExecution; prevent
+    // unhandled-rejection noise.
+    streamingPromise.catch(() => {});
+
+    // Resolves when either: (a) processStream completes/errors, or
+    // (b) the execution is backgrounded externally.
+    const result = await handle.result;
+
+    if (result.backgrounded) {
+      backgrounded = true;
+      const agentLabel = this.definition.displayName ?? this.definition.name;
+      const data: BackgroundExecutionData = {
+        pid: executionId,
+        command: `Remote agent: ${agentLabel}`,
+        initialOutput: result.output,
+      };
+      return {
+        llmContent: [
+          {
+            text: `Remote agent '${agentLabel}' moved to background (ID: ${executionId}). Use subscribe to view output.`,
+          },
+        ],
+        returnDisplay: `Remote agent moved to background (ID: ${executionId}).`,
+        data,
+      };
+    }
+
+    // Error path — the lifecycle result carries the original Error instance.
+    if (result.error) {
+      const errorMessage = this.formatExecutionError(result.error);
+      const fullDisplay = result.output
+        ? `${result.output}\n\n${errorMessage}`
+        : errorMessage;
+      return {
+        llmContent: [{ text: fullDisplay }],
+        returnDisplay: fullDisplay,
+        error: { message: errorMessage },
+      };
+    }
+
+    // Normal completion.
+    const finalOutput = result.output;
+    debugLogger.debug(
+      `[RemoteAgent] Final output from ${this.definition.name}: ${finalOutput.substring(0, 200)}`,
+    );
+    return {
+      llmContent: [{ text: finalOutput }],
+      returnDisplay: safeJsonToMarkdown(finalOutput),
+    };
+  }
+
+  /**
+   * Runs the A2A stream, feeding output deltas into the lifecycle service.
+   * On completion (or error) it settles the lifecycle execution so
+   * {@link execute}'s `handle.result` resolves.
+   */
+  private async processStream(
+    executionId: number,
+    signal: AbortSignal,
+    updateOutput?: (output: string | AnsiOutput) => void,
+  ): Promise<void> {
     const reassembler = new A2AResultReassembler();
+    let previousOutputLength = 0;
+
     try {
       const priorState = RemoteAgentInvocation.sessionState.get(
         this.definition.name,
@@ -150,21 +255,30 @@ export class RemoteAgentInvocation extends BaseToolInvocation<
         {
           contextId: this.contextId,
           taskId: this.taskId,
-          signal: _signal,
+          signal,
         },
       );
 
       let finalResponse: SendMessageResult | undefined;
 
       for await (const chunk of stream) {
-        if (_signal.aborted) {
+        if (signal.aborted) {
           throw new Error('Operation aborted');
         }
         finalResponse = chunk;
         reassembler.update(chunk);
 
+        // Compute delta so lifecycle subscribers see incremental chunks.
+        const currentOutput = reassembler.toString();
+        const delta = currentOutput.substring(previousOutputLength);
+        previousOutputLength = currentOutput.length;
+
+        if (delta) {
+          ExecutionLifecycleService.appendOutput(executionId, delta);
+        }
+
         if (updateOutput) {
-          updateOutput(reassembler.toString());
+          updateOutput(currentOutput);
         }
 
         const {
@@ -184,33 +298,22 @@ export class RemoteAgentInvocation extends BaseToolInvocation<
         throw new Error('No response from remote agent.');
       }
 
-      const finalOutput = reassembler.toString();
-
       debugLogger.debug(
         `[RemoteAgent] Final response from ${this.definition.name}:\n${JSON.stringify(finalResponse, null, 2)}`,
       );
 
-      return {
-        llmContent: [{ text: finalOutput }],
-        returnDisplay: safeJsonToMarkdown(finalOutput),
-      };
+      ExecutionLifecycleService.completeExecution(executionId);
     } catch (error: unknown) {
-      const partialOutput = reassembler.toString();
-      // Surface structured, user-friendly error messages.
-      const errorMessage = this.formatExecutionError(error);
-      const fullDisplay = partialOutput
-        ? `${partialOutput}\n\n${errorMessage}`
-        : errorMessage;
-      return {
-        llmContent: [{ text: fullDisplay }],
-        returnDisplay: fullDisplay,
-        error: { message: errorMessage },
-      };
+      ExecutionLifecycleService.completeExecution(executionId, {
+        error: error instanceof Error ? error : new Error(String(error)),
+      });
     } finally {
-      // Persist state even on partial failures or aborts to maintain conversational continuity.
+      // Persist conversational state. On abort/kill the task was interrupted
+      // so clear taskId (next invocation starts a fresh task), but keep
+      // contextId to maintain the conversation with the remote agent.
       RemoteAgentInvocation.sessionState.set(this.definition.name, {
         contextId: this.contextId,
-        taskId: this.taskId,
+        taskId: signal.aborted ? undefined : this.taskId,
       });
     }
   }

packages/core/src/agents/subagent-tool.test.ts

@@ -189,6 +189,7 @@ describe('SubAgentInvocation', () => {
     expect(mockInnerInvocation.execute).toHaveBeenCalledWith(
       abortSignal,
       updateOutput,
+      undefined,
     );
 
     expect(runInDevTraceSpan).toHaveBeenCalledWith(

packages/core/src/agents/subagent-tool.ts

@@ -13,6 +13,7 @@ import {
   type ToolCallConfirmationDetails,
   isTool,
   type ToolLiveOutput,
+  type ExecuteOptions,
 } from '../tools/tools.js';
 import type { Config } from '../config/config.js';
 import { type AgentLoopContext } from '../config/agent-loop-context.js';
@@ -161,6 +162,7 @@ class SubAgentInvocation extends BaseToolInvocation<AgentInputs, ToolResult> {
   async execute(
     signal: AbortSignal,
     updateOutput?: (output: ToolLiveOutput) => void,
+    options?: ExecuteOptions,
   ): Promise<ToolResult> {
     const validationError = SchemaValidator.validate(
       this.definition.inputConfig.inputSchema,
@@ -188,7 +190,7 @@ class SubAgentInvocation extends BaseToolInvocation<AgentInputs, ToolResult> {
       },
       async ({ metadata }) => {
         metadata.input = this.params;
-        const result = await invocation.execute(signal, updateOutput);
+        const result = await invocation.execute(signal, updateOutput, options);
         metadata.output = result;
         return result;
       },

packages/core/src/index.ts

@@ -162,6 +162,12 @@ export * from './services/executionLifecycleService.js';
 // Export Injection Service
 export * from './config/injectionService.js';
 
+// Export Execution Lifecycle Service
+export * from './services/executionLifecycleService.js';
+
+// Export Injection Service
+export * from './config/injectionService.js';
+
 // Export base tool definitions
 export * from './tools/tools.js';
 export * from './tools/tool-error.js';

packages/core/src/services/executionLifecycleService.test.ts

@@ -10,6 +10,7 @@ import {
   type ExecutionHandle,
   type ExecutionResult,
 } from './executionLifecycleService.js';
+import { InjectionService } from '../config/injectionService.js';
 
 function createResult(
   overrides: Partial<ExecutionResult> = {},
@@ -296,6 +297,81 @@ describe('ExecutionLifecycleService', () => {
     }).toThrow('Execution 4324 is already attached.');
   });
 
+  describe('Background Start Listeners', () => {
+    it('fires onBackground when an execution is backgrounded', async () => {
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackground(listener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'remote_agent',
+        undefined,
+        'My Remote Agent',
+      );
+      const executionId = handle.pid!;
+
+      ExecutionLifecycleService.appendOutput(executionId, 'some output');
+      ExecutionLifecycleService.background(executionId);
+      await handle.result;
+
+      expect(listener).toHaveBeenCalledTimes(1);
+      const info = listener.mock.calls[0][0];
+      expect(info.executionId).toBe(executionId);
+      expect(info.executionMethod).toBe('remote_agent');
+      expect(info.label).toBe('My Remote Agent');
+      expect(info.output).toBe('some output');
+
+      ExecutionLifecycleService.offBackground(listener);
+    });
+
+    it('uses fallback label when none is provided', async () => {
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackground(listener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'none',
+      );
+      const executionId = handle.pid!;
+
+      ExecutionLifecycleService.background(executionId);
+      await handle.result;
+
+      const info = listener.mock.calls[0][0];
+      expect(info.label).toContain('none');
+      expect(info.label).toContain(String(executionId));
+
+      ExecutionLifecycleService.offBackground(listener);
+    });
+
+    it('does not fire onBackground for non-backgrounded completions', async () => {
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackground(listener);
+
+      const handle = ExecutionLifecycleService.createExecution();
+      ExecutionLifecycleService.completeExecution(handle.pid!);
+      await handle.result;
+
+      expect(listener).not.toHaveBeenCalled();
+
+      ExecutionLifecycleService.offBackground(listener);
+    });
+
+    it('offBackground removes the listener', async () => {
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackground(listener);
+      ExecutionLifecycleService.offBackground(listener);
+
+      const handle = ExecutionLifecycleService.createExecution();
+      ExecutionLifecycleService.background(handle.pid!);
+      await handle.result;
+
+      expect(listener).not.toHaveBeenCalled();
+    });
+  });
+
   describe('Background Completion Listeners', () => {
     it('fires onBackgroundComplete with formatInjection text when backgrounded execution settles', async () => {
       const listener = vi.fn();
@@ -327,6 +403,7 @@ describe('ExecutionLifecycleService', () => {
       expect(info.output).toBe('agent output');
       expect(info.error).toBeNull();
       expect(info.injectionText).toBe('[Agent completed]\nagent output');
+      expect(info.completionBehavior).toBe('inject');
 
       ExecutionLifecycleService.offBackgroundComplete(listener);
     });
@@ -358,7 +435,7 @@ describe('ExecutionLifecycleService', () => {
       ExecutionLifecycleService.offBackgroundComplete(listener);
     });
 
-    it('sets injectionText to null when no formatInjection callback is provided', async () => {
+    it('sets injectionText to null and completionBehavior to silent when no formatInjection is provided', async () => {
       const listener = vi.fn();
       ExecutionLifecycleService.onBackgroundComplete(listener);
 
@@ -377,6 +454,7 @@ describe('ExecutionLifecycleService', () => {
 
       expect(listener).toHaveBeenCalledTimes(1);
       expect(listener.mock.calls[0][0].injectionText).toBeNull();
+      expect(listener.mock.calls[0][0].completionBehavior).toBe('silent');
 
       ExecutionLifecycleService.offBackgroundComplete(listener);
     });
@@ -443,5 +521,167 @@ describe('ExecutionLifecycleService', () => {
 
       expect(listener).not.toHaveBeenCalled();
     });
+
+    it('explicit notify behavior includes injectionText and auto-dismiss signal', async () => {
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackgroundComplete(listener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'child_process',
+        () => '[Command completed. Output saved to /tmp/bg.log]',
+        undefined,
+        'notify',
+      );
+      const executionId = handle.pid!;
+
+      ExecutionLifecycleService.background(executionId);
+      await handle.result;
+
+      ExecutionLifecycleService.completeExecution(executionId);
+
+      expect(listener).toHaveBeenCalledTimes(1);
+      const info = listener.mock.calls[0][0];
+      expect(info.completionBehavior).toBe('notify');
+      expect(info.injectionText).toBe(
+        '[Command completed. Output saved to /tmp/bg.log]',
+      );
+
+      ExecutionLifecycleService.offBackgroundComplete(listener);
+    });
+
+    it('explicit silent behavior skips injection even when formatInjection is provided', async () => {
+      const formatFn = vi.fn().mockReturnValue('should not appear');
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackgroundComplete(listener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'none',
+        formatFn,
+        undefined,
+        'silent',
+      );
+      const executionId = handle.pid!;
+
+      ExecutionLifecycleService.background(executionId);
+      await handle.result;
+
+      ExecutionLifecycleService.completeExecution(executionId);
+
+      expect(listener).toHaveBeenCalledTimes(1);
+      const info = listener.mock.calls[0][0];
+      expect(info.completionBehavior).toBe('silent');
+      expect(info.injectionText).toBeNull();
+      expect(formatFn).not.toHaveBeenCalled();
+
+      ExecutionLifecycleService.offBackgroundComplete(listener);
+    });
+
+    it('includes completionBehavior in BackgroundStartInfo', async () => {
+      const bgStartListener = vi.fn();
+      ExecutionLifecycleService.onBackground(bgStartListener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'remote_agent',
+        () => 'text',
+        'test-label',
+        'inject',
+      );
+
+      ExecutionLifecycleService.background(handle.pid!);
+      await handle.result;
+
+      expect(bgStartListener).toHaveBeenCalledTimes(1);
+      expect(bgStartListener.mock.calls[0][0].completionBehavior).toBe(
+        'inject',
+      );
+
+      ExecutionLifecycleService.offBackground(bgStartListener);
+    });
+
+    it('completionBehavior flows through attachExecution', async () => {
+      const listener = vi.fn();
+      ExecutionLifecycleService.onBackgroundComplete(listener);
+
+      const handle = ExecutionLifecycleService.attachExecution(9999, {
+        executionMethod: 'child_process',
+        formatInjection: () => '[notify message]',
+        completionBehavior: 'notify',
+      });
+
+      ExecutionLifecycleService.background(9999);
+      await handle.result;
+
+      ExecutionLifecycleService.completeWithResult(
+        9999,
+        createResult({ pid: 9999, executionMethod: 'child_process' }),
+      );
+
+      expect(listener).toHaveBeenCalledTimes(1);
+      const info = listener.mock.calls[0][0];
+      expect(info.completionBehavior).toBe('notify');
+      expect(info.injectionText).toBe('[notify message]');
+
+      ExecutionLifecycleService.offBackgroundComplete(listener);
+    });
+
+    it('injects directly into InjectionService when wired via setInjectionService', async () => {
+      const injectionService = new InjectionService(() => true);
+      ExecutionLifecycleService.setInjectionService(injectionService);
+
+      const injectionListener = vi.fn();
+      injectionService.onInjection(injectionListener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'remote_agent',
+        (output) => `[Completed] ${output}`,
+        undefined,
+        'inject',
+      );
+      const executionId = handle.pid!;
+
+      ExecutionLifecycleService.appendOutput(executionId, 'agent output');
+      ExecutionLifecycleService.background(executionId);
+      await handle.result;
+
+      ExecutionLifecycleService.completeExecution(executionId);
+
+      expect(injectionListener).toHaveBeenCalledWith(
+        '[Completed] agent output',
+        'background_completion',
+      );
+    });
+
+    it('does not inject into InjectionService for silent behavior', async () => {
+      const injectionService = new InjectionService(() => true);
+      ExecutionLifecycleService.setInjectionService(injectionService);
+
+      const injectionListener = vi.fn();
+      injectionService.onInjection(injectionListener);
+
+      const handle = ExecutionLifecycleService.createExecution(
+        '',
+        undefined,
+        'none',
+        () => 'should not inject',
+        undefined,
+        'silent',
+      );
+      const executionId = handle.pid!;
+
+      ExecutionLifecycleService.background(executionId);
+      await handle.result;
+
+      ExecutionLifecycleService.completeExecution(executionId);
+
+      expect(injectionListener).not.toHaveBeenCalled();
+    });
   });
 });

packages/core/src/services/executionLifecycleService.ts

@@ -59,12 +59,16 @@ export interface ExecutionCompletionOptions {
 
 export interface ExternalExecutionRegistration {
   executionMethod: ExecutionMethod;
+  /** Human-readable label for the background task UI (e.g. the command string). */
+  label?: string;
   initialOutput?: string;
   getBackgroundOutput?: () => string;
   getSubscriptionSnapshot?: () => string | AnsiOutput | undefined;
   writeInput?: (input: string) => void;
   kill?: () => void;
   isActive?: () => boolean;
+  formatInjection?: FormatInjectionFn;
+  completionBehavior?: CompletionBehavior;
 }
 
 /**
@@ -77,15 +81,41 @@ export type FormatInjectionFn = (
   error: Error | null,
 ) => string | null;
 
+/**
+ * Controls what happens when a backgrounded execution completes:
+ * - `'inject'`  — full formatted output is injected into the conversation; task auto-dismisses from UI.
+ * - `'notify'`  — a short pointer (e.g. "output saved to /tmp/...") is injected; task auto-dismisses from UI.
+ * - `'silent'`  — nothing is injected; task stays in the UI until manually dismissed.
+ *
+ * The distinction between `inject` and `notify` is semantic for now (both inject + dismiss),
+ * but enables the system to treat them differently in the future (e.g. LLM-decided injection).
+ */
+export type CompletionBehavior = 'inject' | 'notify' | 'silent';
+
 interface ManagedExecutionBase {
   executionMethod: ExecutionMethod;
+  label?: string;
   output: string;
   backgrounded?: boolean;
   formatInjection?: FormatInjectionFn;
+  completionBehavior?: CompletionBehavior;
   getBackgroundOutput?: () => string;
   getSubscriptionSnapshot?: () => string | AnsiOutput | undefined;
 }
 
+/**
+ * Payload emitted when an execution is moved to the background.
+ */
+export interface BackgroundStartInfo {
+  executionId: number;
+  executionMethod: ExecutionMethod;
+  label: string;
+  output: string;
+  completionBehavior: CompletionBehavior;
+}
+
+export type BackgroundStartListener = (info: BackgroundStartInfo) => void;
+
 /**
  * Payload emitted when a previously-backgrounded execution settles.
  */
@@ -96,6 +126,7 @@ export interface BackgroundCompletionInfo {
   error: Error | null;
   /** Pre-formatted injection text from the execution creator, or `null` if skipped. */
   injectionText: string | null;
+  completionBehavior: CompletionBehavior;
 }
 
 export type BackgroundCompletionListener = (
@@ -124,6 +155,16 @@ const NON_PROCESS_EXECUTION_ID_START = 2_000_000_000;
 export class ExecutionLifecycleService {
   private static readonly EXIT_INFO_TTL_MS = 5 * 60 * 1000;
   private static nextExecutionId = NON_PROCESS_EXECUTION_ID_START;
+  private static injectionService: InjectionService | null = null;
+
+  /**
+   * Connects the lifecycle service to the injection service so that
+   * backgrounded executions are reinjected into the model conversation
+   * directly from the backend — no UI hop needed.
+   */
+  static setInjectionService(service: InjectionService): void {
+    this.injectionService = service;
+  }
 
   private static activeExecutions = new Map<number, ManagedExecutionState>();
   private static activeResolvers = new Map<
@@ -140,14 +181,22 @@ export class ExecutionLifecycleService {
   >();
   private static backgroundCompletionListeners =
     new Set<BackgroundCompletionListener>();
-  private static injectionService: InjectionService | null = null;
+
+  private static backgroundStartListeners = new Set<BackgroundStartListener>();
 
   /**
-   * Wires a singleton InjectionService so that backgrounded executions
-   * can inject their output directly without routing through the UI layer.
+   * Registers a listener that fires when any execution is moved to the background.
+   * This is the hook for the UI to automatically discover backgrounded executions.
    */
-  static setInjectionService(service: InjectionService): void {
-    this.injectionService = service;
+  static onBackground(listener: BackgroundStartListener): void {
+    this.backgroundStartListeners.add(listener);
+  }
+
+  /**
+   * Unregisters a background start listener.
+   */
+  static offBackground(listener: BackgroundStartListener): void {
+    this.backgroundStartListeners.delete(listener);
   }
 
   /**
@@ -222,6 +271,7 @@ export class ExecutionLifecycleService {
     this.exitedExecutionInfo.clear();
     this.backgroundCompletionListeners.clear();
     this.injectionService = null;
+    this.backgroundStartListeners.clear();
     this.nextExecutionId = NON_PROCESS_EXECUTION_ID_START;
   }
 
@@ -239,6 +289,7 @@ export class ExecutionLifecycleService {
 
     this.activeExecutions.set(executionId, {
       executionMethod: registration.executionMethod,
+      label: registration.label,
       output: registration.initialOutput ?? '',
       kind: 'external',
       getBackgroundOutput: registration.getBackgroundOutput,
@@ -246,6 +297,8 @@ export class ExecutionLifecycleService {
       writeInput: registration.writeInput,
       kill: registration.kill,
       isActive: registration.isActive,
+      formatInjection: registration.formatInjection,
+      completionBehavior: registration.completionBehavior,
     });
 
     return {
@@ -259,15 +312,19 @@ export class ExecutionLifecycleService {
     onKill?: () => void,
     executionMethod: ExecutionMethod = 'none',
     formatInjection?: FormatInjectionFn,
+    label?: string,
+    completionBehavior?: CompletionBehavior,
   ): ExecutionHandle {
     const executionId = this.allocateExecutionId();
 
     this.activeExecutions.set(executionId, {
       executionMethod,
+      label,
       output: initialOutput,
       kind: 'virtual',
       onKill,
       formatInjection,
+      completionBehavior,
       getBackgroundOutput: () => {
         const state = this.activeExecutions.get(executionId);
         return state?.output ?? initialOutput;
@@ -325,19 +382,15 @@ export class ExecutionLifecycleService {
 
     // Fire background completion listeners if this was a backgrounded execution.
     if (execution.backgrounded && !result.aborted) {
-      const injectionText = execution.formatInjection
-        ? execution.formatInjection(result.output, result.error)
-        : null;
-      const info: BackgroundCompletionInfo = {
-        executionId,
-        executionMethod: execution.executionMethod,
-        output: result.output,
-        error: result.error,
-        injectionText,
-      };
+      const behavior =
+        execution.completionBehavior ??
+        (execution.formatInjection ? 'inject' : 'silent');
+      const injectionText =
+        behavior !== 'silent' && execution.formatInjection
+          ? execution.formatInjection(result.output, result.error)
+          : null;
 
-      // Inject directly into the model conversation if injection text is
-      // available and the injection service has been wired up.
+      // Inject directly into the model conversation from the backend.
       if (injectionText && this.injectionService) {
         this.injectionService.addInjection(
           injectionText,
@@ -345,6 +398,15 @@ export class ExecutionLifecycleService {
         );
       }
 
+      const info: BackgroundCompletionInfo = {
+        executionId,
+        executionMethod: execution.executionMethod,
+        output: result.output,
+        error: result.error,
+        injectionText,
+        completionBehavior: behavior,
+      };
+
       for (const listener of this.backgroundCompletionListeners) {
         try {
           listener(info);
@@ -434,6 +496,21 @@ export class ExecutionLifecycleService {
 
     this.activeResolvers.delete(executionId);
     execution.backgrounded = true;
+
+    // Notify listeners that an execution was moved to the background.
+    const info: BackgroundStartInfo = {
+      executionId,
+      executionMethod: execution.executionMethod,
+      label:
+        execution.label ?? `${execution.executionMethod} (ID: ${executionId})`,
+      output,
+      completionBehavior:
+        execution.completionBehavior ??
+        (execution.formatInjection ? 'inject' : 'silent'),
+    };
+    for (const listener of this.backgroundStartListeners) {
+      listener(info);
+    }
   }
 
   static subscribe(

packages/core/src/services/shellExecutionService.ts

@@ -488,6 +488,14 @@ export class ShellExecutionService {
                 return false;
               }
             },
+            formatInjection: (_output, error) => {
+              const logPath = ShellExecutionService.getLogFilePath(child.pid!);
+              const status = error
+                ? `with error: ${error.message}`
+                : 'successfully';
+              return `[Background command completed ${status}. Output saved to ${logPath}]`;
+            },
+            completionBehavior: 'inject',
           })
         : undefined;
 
@@ -844,6 +852,14 @@ export class ShellExecutionService {
           );
           return bufferData.length > 0 ? bufferData : undefined;
         },
+        formatInjection: (_output, error) => {
+          const logPath = ShellExecutionService.getLogFilePath(ptyPid);
+          const status = error
+            ? `with error: ${error.message}`
+            : 'successfully';
+          return `[Background command completed ${status}. Output saved to ${logPath}]`;
+        },
+        completionBehavior: 'inject',
       }).result;
 
       let processingChain = Promise.resolve();