Subagent activity UX. (#17570)

packages/core/src/tools/shell.ts

@@ -17,6 +17,7 @@ import type {
   ToolCallConfirmationDetails,
   ToolExecuteConfirmationDetails,
   PolicyUpdateOptions,
+  ToolLiveOutput,
 } from './tools.js';
 import {
   BaseDeclarativeTool,
@@ -149,7 +150,7 @@ export class ShellToolInvocation extends BaseToolInvocation<
 
   async execute(
     signal: AbortSignal,
-    updateOutput?: (output: string | AnsiOutput) => void,
+    updateOutput?: (output: ToolLiveOutput) => void,
     shellExecutionConfig?: ShellExecutionConfig,
     setPidCallback?: (pid: number) => void,
   ): Promise<ToolResult> {

packages/core/src/tools/tools.ts

@@ -19,6 +19,7 @@ import {
   type Question,
 } from '../confirmation-bus/types.js';
 import { type ApprovalMode } from '../policy/types.js';
+import type { SubagentProgress } from '../agents/types.js';
 
 /**
  * Represents a validated and ready-to-execute tool call.
@@ -64,7 +65,7 @@ export interface ToolInvocation<
    */
   execute(
     signal: AbortSignal,
-    updateOutput?: (output: string | AnsiOutput) => void,
+    updateOutput?: (output: ToolLiveOutput) => void,
     shellExecutionConfig?: ShellExecutionConfig,
   ): Promise<TResult>;
 }
@@ -276,7 +277,7 @@ export abstract class BaseToolInvocation<
 
   abstract execute(
     signal: AbortSignal,
-    updateOutput?: (output: string | AnsiOutput) => void,
+    updateOutput?: (output: ToolLiveOutput) => void,
     shellExecutionConfig?: ShellExecutionConfig,
   ): Promise<TResult>;
 }
@@ -422,7 +423,7 @@ export abstract class DeclarativeTool<
   async buildAndExecute(
     params: TParams,
     signal: AbortSignal,
-    updateOutput?: (output: string | AnsiOutput) => void,
+    updateOutput?: (output: ToolLiveOutput) => void,
     shellExecutionConfig?: ShellExecutionConfig,
   ): Promise<TResult> {
     const invocation = this.build(params);
@@ -688,7 +689,14 @@ export interface TodoList {
   todos: Todo[];
 }
 
-export type ToolResultDisplay = string | FileDiff | AnsiOutput | TodoList;
+export type ToolLiveOutput = string | AnsiOutput | SubagentProgress;
+
+export type ToolResultDisplay =
+  | string
+  | FileDiff
+  | AnsiOutput
+  | TodoList
+  | SubagentProgress;
 
 export type TodoStatus = 'pending' | 'in_progress' | 'completed' | 'cancelled';