diff --git a/packages/cli/src/acp-integration/schema.ts b/packages/cli/src/acp-integration/schema.ts
index 1a486818..ac754318 100644
--- a/packages/cli/src/acp-integration/schema.ts
+++ b/packages/cli/src/acp-integration/schema.ts
@@ -328,6 +328,7 @@ export type Usage = z.infer<typeof usageSchema>;
 
 export const sessionUpdateMetaSchema = z.object({
   usage: usageSchema.optional().nullable(),
+  durationMs: z.number().optional().nullable(),
 });
 
 export type SessionUpdateMeta = z.infer<typeof sessionUpdateMetaSchema>;
diff --git a/packages/cli/src/acp-integration/service/filesystem.test.ts b/packages/cli/src/acp-integration/service/filesystem.test.ts
new file mode 100644
index 00000000..70ccfc2d
--- /dev/null
+++ b/packages/cli/src/acp-integration/service/filesystem.test.ts
@@ -0,0 +1,59 @@
+/**
+ * @license
+ * Copyright 2025 Qwen
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, expect, it, vi } from 'vitest';
+import type { FileSystemService } from '@qwen-code/qwen-code-core';
+import { AcpFileSystemService } from './filesystem.js';
+
+const createFallback = (): FileSystemService => ({
+  readTextFile: vi.fn(),
+  writeTextFile: vi.fn(),
+  findFiles: vi.fn().mockReturnValue([]),
+});
+
+describe('AcpFileSystemService', () => {
+  describe('readTextFile ENOENT handling', () => {
+    it('parses path from ACP ENOENT message (quoted)', async () => {
+      const client = {
+        readTextFile: vi
+          .fn()
+          .mockResolvedValue({ content: 'ERROR: ENOENT: "/remote/file.txt"' }),
+      } as unknown as import('../acp.js').Client;
+
+      const svc = new AcpFileSystemService(
+        client,
+        'session-1',
+        { readTextFile: true, writeTextFile: true },
+        createFallback(),
+      );
+
+      await expect(svc.readTextFile('/local/file.txt')).rejects.toMatchObject({
+        code: 'ENOENT',
+        path: '/remote/file.txt',
+      });
+    });
+
+    it('falls back to requested path when none provided', async () => {
+      const client = {
+        readTextFile: vi.fn().mockResolvedValue({ content: 'ERROR: ENOENT:' }),
+      } as unknown as import('../acp.js').Client;
+
+      const svc = new AcpFileSystemService(
+        client,
+        'session-2',
+        { readTextFile: true, writeTextFile: true },
+        createFallback(),
+      );
+
+      await expect(
+        svc.readTextFile('/fallback/path.txt'),
+      ).rejects.toMatchObject({
+        code: 'ENOENT',
+        path: '/fallback/path.txt',
+      });
+    });
+  });
+});
diff --git a/packages/cli/src/acp-integration/service/filesystem.ts b/packages/cli/src/acp-integration/service/filesystem.ts
index af7c26ad..7bcaee2d 100644
--- a/packages/cli/src/acp-integration/service/filesystem.ts
+++ b/packages/cli/src/acp-integration/service/filesystem.ts
@@ -31,10 +31,16 @@ export class AcpFileSystemService implements FileSystemService {
     });
 
     if (response.content.startsWith('ERROR: ENOENT:')) {
+      // Treat ACP error strings as structured ENOENT errors without
+      // assuming a specific platform format.
+      const match = /^ERROR:\s*ENOENT:\s*(?<path>.*)$/i.exec(response.content);
       const err = new Error(response.content) as NodeJS.ErrnoException;
       err.code = 'ENOENT';
       err.errno = -2;
-      err.path = filePath;
+      const rawPath = match?.groups?.['path']?.trim();
+      err['path'] = rawPath
+        ? rawPath.replace(/^['"]|['"]$/g, '') || filePath
+        : filePath;
       throw err;
     }
 
diff --git a/packages/cli/src/acp-integration/session/HistoryReplayer.ts b/packages/cli/src/acp-integration/session/HistoryReplayer.ts
index 1bd11c79..0ecbccb9 100644
--- a/packages/cli/src/acp-integration/session/HistoryReplayer.ts
+++ b/packages/cli/src/acp-integration/session/HistoryReplayer.ts
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import type { ChatRecord } from '@qwen-code/qwen-code-core';
+import type { ChatRecord, TaskResultDisplay } from '@qwen-code/qwen-code-core';
 import type {
   Content,
   GenerateContentResponseUsageMetadata,
@@ -135,6 +135,54 @@ export class HistoryReplayer {
       // Note: args aren't stored in tool_result records by default
       args: undefined,
     });
+
+    // Special handling: Task tool execution summary contains token usage
+    const { resultDisplay } = result ?? {};
+    if (
+      !!resultDisplay &&
+      typeof resultDisplay === 'object' &&
+      'type' in resultDisplay &&
+      (resultDisplay as { type?: unknown }).type === 'task_execution'
+    ) {
+      await this.emitTaskUsageFromResultDisplay(
+        resultDisplay as TaskResultDisplay,
+      );
+    }
+  }
+
+  /**
+   * Emits token usage from a TaskResultDisplay execution summary, if present.
+   */
+  private async emitTaskUsageFromResultDisplay(
+    resultDisplay: TaskResultDisplay,
+  ): Promise<void> {
+    const summary = resultDisplay.executionSummary;
+    if (!summary) {
+      return;
+    }
+
+    const usageMetadata: GenerateContentResponseUsageMetadata = {};
+
+    if (Number.isFinite(summary.inputTokens)) {
+      usageMetadata.promptTokenCount = summary.inputTokens;
+    }
+    if (Number.isFinite(summary.outputTokens)) {
+      usageMetadata.candidatesTokenCount = summary.outputTokens;
+    }
+    if (Number.isFinite(summary.thoughtTokens)) {
+      usageMetadata.thoughtsTokenCount = summary.thoughtTokens;
+    }
+    if (Number.isFinite(summary.cachedTokens)) {
+      usageMetadata.cachedContentTokenCount = summary.cachedTokens;
+    }
+    if (Number.isFinite(summary.totalTokens)) {
+      usageMetadata.totalTokenCount = summary.totalTokens;
+    }
+
+    // Only emit if we captured at least one token metric
+    if (Object.keys(usageMetadata).length > 0) {
+      await this.messageEmitter.emitUsageMetadata(usageMetadata);
+    }
   }
 
   /**
diff --git a/packages/cli/src/acp-integration/session/Session.ts b/packages/cli/src/acp-integration/session/Session.ts
index a6466d1e..1d90ed20 100644
--- a/packages/cli/src/acp-integration/session/Session.ts
+++ b/packages/cli/src/acp-integration/session/Session.ts
@@ -4,7 +4,12 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import type { Content, FunctionCall, Part } from '@google/genai';
+import type {
+  Content,
+  FunctionCall,
+  GenerateContentResponseUsageMetadata,
+  Part,
+} from '@google/genai';
 import type {
   Config,
   GeminiChat,
@@ -195,6 +200,8 @@ export class Session implements SessionContext {
       }
 
       const functionCalls: FunctionCall[] = [];
+      let usageMetadata: GenerateContentResponseUsageMetadata | null = null;
+      const streamStartTime = Date.now();
 
       try {
         const responseStream = await chat.sendMessageStream(
@@ -225,22 +232,16 @@ export class Session implements SessionContext {
                 continue;
               }
 
-              const content: acp.ContentBlock = {
-                type: 'text',
-                text: part.text,
-              };
-
-              this.sendUpdate({
-                sessionUpdate: part.thought
-                  ? 'agent_thought_chunk'
-                  : 'agent_message_chunk',
-                content,
-              });
+              this.messageEmitter.emitMessage(
+                part.text,
+                'assistant',
+                part.thought,
+              );
             }
           }
 
           if (resp.type === StreamEventType.CHUNK && resp.value.usageMetadata) {
-            this.messageEmitter.emitUsageMetadata(resp.value.usageMetadata);
+            usageMetadata = resp.value.usageMetadata;
           }
 
           if (resp.type === StreamEventType.CHUNK && resp.value.functionCalls) {
@@ -258,6 +259,15 @@ export class Session implements SessionContext {
         throw error;
       }
 
+      if (usageMetadata) {
+        const durationMs = Date.now() - streamStartTime;
+        await this.messageEmitter.emitUsageMetadata(
+          usageMetadata,
+          '',
+          durationMs,
+        );
+      }
+
       if (functionCalls.length > 0) {
         const toolResponseParts: Part[] = [];
 
diff --git a/packages/cli/src/acp-integration/session/SubAgentTracker.ts b/packages/cli/src/acp-integration/session/SubAgentTracker.ts
index c6c83292..1e745b92 100644
--- a/packages/cli/src/acp-integration/session/SubAgentTracker.ts
+++ b/packages/cli/src/acp-integration/session/SubAgentTracker.ts
@@ -9,6 +9,7 @@ import type {
   SubAgentToolCallEvent,
   SubAgentToolResultEvent,
   SubAgentApprovalRequestEvent,
+  SubAgentUsageEvent,
   ToolCallConfirmationDetails,
   AnyDeclarativeTool,
   AnyToolInvocation,
@@ -20,6 +21,7 @@ import {
 import { z } from 'zod';
 import type { SessionContext } from './types.js';
 import { ToolCallEmitter } from './emitters/ToolCallEmitter.js';
+import { MessageEmitter } from './emitters/MessageEmitter.js';
 import type * as acp from '../acp.js';
 
 /**
@@ -62,6 +64,7 @@ const basicPermissionOptions: readonly PermissionOptionConfig[] = [
  */
 export class SubAgentTracker {
   private readonly toolCallEmitter: ToolCallEmitter;
+  private readonly messageEmitter: MessageEmitter;
   private readonly toolStates = new Map<
     string,
     {
@@ -76,6 +79,7 @@ export class SubAgentTracker {
     private readonly client: acp.Client,
   ) {
     this.toolCallEmitter = new ToolCallEmitter(ctx);
+    this.messageEmitter = new MessageEmitter(ctx);
   }
 
   /**
@@ -92,16 +96,19 @@ export class SubAgentTracker {
     const onToolCall = this.createToolCallHandler(abortSignal);
     const onToolResult = this.createToolResultHandler(abortSignal);
     const onApproval = this.createApprovalHandler(abortSignal);
+    const onUsageMetadata = this.createUsageMetadataHandler(abortSignal);
 
     eventEmitter.on(SubAgentEventType.TOOL_CALL, onToolCall);
     eventEmitter.on(SubAgentEventType.TOOL_RESULT, onToolResult);
     eventEmitter.on(SubAgentEventType.TOOL_WAITING_APPROVAL, onApproval);
+    eventEmitter.on(SubAgentEventType.USAGE_METADATA, onUsageMetadata);
 
     return [
       () => {
         eventEmitter.off(SubAgentEventType.TOOL_CALL, onToolCall);
         eventEmitter.off(SubAgentEventType.TOOL_RESULT, onToolResult);
         eventEmitter.off(SubAgentEventType.TOOL_WAITING_APPROVAL, onApproval);
+        eventEmitter.off(SubAgentEventType.USAGE_METADATA, onUsageMetadata);
         // Clean up any remaining states
         this.toolStates.clear();
       },
@@ -252,6 +259,20 @@ export class SubAgentTracker {
     };
   }
 
+  /**
+   * Creates a handler for usage metadata events.
+   */
+  private createUsageMetadataHandler(
+    abortSignal: AbortSignal,
+  ): (...args: unknown[]) => void {
+    return (...args: unknown[]) => {
+      const event = args[0] as SubAgentUsageEvent;
+      if (abortSignal.aborted) return;
+
+      this.messageEmitter.emitUsageMetadata(event.usage, '', event.durationMs);
+    };
+  }
+
   /**
    * Converts confirmation details to permission options for the client.
    */
diff --git a/packages/cli/src/acp-integration/session/emitters/MessageEmitter.test.ts b/packages/cli/src/acp-integration/session/emitters/MessageEmitter.test.ts
index 7720d1f1..d0b1ae87 100644
--- a/packages/cli/src/acp-integration/session/emitters/MessageEmitter.test.ts
+++ b/packages/cli/src/acp-integration/session/emitters/MessageEmitter.test.ts
@@ -175,5 +175,32 @@ describe('MessageEmitter', () => {
         },
       });
     });
+
+    it('should include durationMs in _meta when provided', async () => {
+      const usageMetadata = {
+        promptTokenCount: 10,
+        candidatesTokenCount: 5,
+        thoughtsTokenCount: 2,
+        totalTokenCount: 17,
+        cachedContentTokenCount: 1,
+      };
+
+      await emitter.emitUsageMetadata(usageMetadata, 'done', 1234);
+
+      expect(sendUpdateSpy).toHaveBeenCalledWith({
+        sessionUpdate: 'agent_message_chunk',
+        content: { type: 'text', text: 'done' },
+        _meta: {
+          usage: {
+            promptTokens: 10,
+            completionTokens: 5,
+            thoughtsTokens: 2,
+            totalTokens: 17,
+            cachedTokens: 1,
+          },
+          durationMs: 1234,
+        },
+      });
+    });
   });
 });
diff --git a/packages/cli/src/acp-integration/session/emitters/MessageEmitter.ts b/packages/cli/src/acp-integration/session/emitters/MessageEmitter.ts
index 00770922..39cdf6a7 100644
--- a/packages/cli/src/acp-integration/session/emitters/MessageEmitter.ts
+++ b/packages/cli/src/acp-integration/session/emitters/MessageEmitter.ts
@@ -52,6 +52,7 @@ export class MessageEmitter extends BaseEmitter {
   async emitUsageMetadata(
     usageMetadata: GenerateContentResponseUsageMetadata,
     text: string = '',
+    durationMs?: number,
   ): Promise<void> {
     const usage: Usage = {
       promptTokens: usageMetadata.promptTokenCount,
@@ -61,10 +62,13 @@ export class MessageEmitter extends BaseEmitter {
       cachedTokens: usageMetadata.cachedContentTokenCount,
     };
 
+    const meta =
+      typeof durationMs === 'number' ? { usage, durationMs } : { usage };
+
     await this.sendUpdate({
       sessionUpdate: 'agent_message_chunk',
       content: { type: 'text', text },
-      _meta: { usage },
+      _meta: meta,
     });
   }
 
diff --git a/packages/cli/src/acp-integration/session/emitters/ToolCallEmitter.ts b/packages/cli/src/acp-integration/session/emitters/ToolCallEmitter.ts
index 3ac514c0..9859ed78 100644
--- a/packages/cli/src/acp-integration/session/emitters/ToolCallEmitter.ts
+++ b/packages/cli/src/acp-integration/session/emitters/ToolCallEmitter.ts
@@ -279,10 +279,14 @@ export class ToolCallEmitter extends BaseEmitter {
             string,
             unknown
           >;
+          const outputField = resp['output'];
+          const errorField = resp['error'];
           const responseText =
-            (resp['output'] as string) ??
-            (resp['error'] as string) ??
-            JSON.stringify(resp);
+            typeof outputField === 'string'
+              ? outputField
+              : typeof errorField === 'string'
+                ? errorField
+                : JSON.stringify(resp);
           result.push({
             type: 'content',
             content: { type: 'text', text: responseText },
diff --git a/packages/core/src/subagents/index.ts b/packages/core/src/subagents/index.ts
index 5560b4fd..17c62a20 100644
--- a/packages/core/src/subagents/index.ts
+++ b/packages/core/src/subagents/index.ts
@@ -58,6 +58,7 @@ export type {
   SubAgentStartEvent,
   SubAgentRoundEvent,
   SubAgentStreamTextEvent,
+  SubAgentUsageEvent,
   SubAgentToolCallEvent,
   SubAgentToolResultEvent,
   SubAgentFinishEvent,
diff --git a/packages/core/src/subagents/subagent-events.ts b/packages/core/src/subagents/subagent-events.ts
index 3c93112d..1f793308 100644
--- a/packages/core/src/subagents/subagent-events.ts
+++ b/packages/core/src/subagents/subagent-events.ts
@@ -10,7 +10,7 @@ import type {
   ToolConfirmationOutcome,
   ToolResultDisplay,
 } from '../tools/tools.js';
-import type { Part } from '@google/genai';
+import type { Part, GenerateContentResponseUsageMetadata } from '@google/genai';
 
 export type SubAgentEvent =
   | 'start'
@@ -20,6 +20,7 @@ export type SubAgentEvent =
   | 'tool_call'
   | 'tool_result'
   | 'tool_waiting_approval'
+  | 'usage_metadata'
   | 'finish'
   | 'error';
 
@@ -31,6 +32,7 @@ export enum SubAgentEventType {
   TOOL_CALL = 'tool_call',
   TOOL_RESULT = 'tool_result',
   TOOL_WAITING_APPROVAL = 'tool_waiting_approval',
+  USAGE_METADATA = 'usage_metadata',
   FINISH = 'finish',
   ERROR = 'error',
 }
@@ -57,6 +59,14 @@ export interface SubAgentStreamTextEvent {
   timestamp: number;
 }
 
+export interface SubAgentUsageEvent {
+  subagentId: string;
+  round: number;
+  usage: GenerateContentResponseUsageMetadata;
+  durationMs?: number;
+  timestamp: number;
+}
+
 export interface SubAgentToolCallEvent {
   subagentId: string;
   round: number;
diff --git a/packages/core/src/subagents/subagent-statistics.test.ts b/packages/core/src/subagents/subagent-statistics.test.ts
index 5b4ae3c6..39ba70aa 100644
--- a/packages/core/src/subagents/subagent-statistics.test.ts
+++ b/packages/core/src/subagents/subagent-statistics.test.ts
@@ -50,6 +50,15 @@ describe('SubagentStatistics', () => {
       expect(summary.outputTokens).toBe(600);
       expect(summary.totalTokens).toBe(1800);
     });
+
+    it('should track thought and cached tokens', () => {
+      stats.recordTokens(100, 50, 10, 5);
+
+      const summary = stats.getSummary();
+      expect(summary.thoughtTokens).toBe(10);
+      expect(summary.cachedTokens).toBe(5);
+      expect(summary.totalTokens).toBe(165); // 100 + 50 + 10 + 5
+    });
   });
 
   describe('tool usage statistics', () => {
@@ -93,14 +102,14 @@ describe('SubagentStatistics', () => {
       stats.start(baseTime);
       stats.setRounds(2);
       stats.recordToolCall('file_read', true, 100);
-      stats.recordTokens(1000, 500);
+      stats.recordTokens(1000, 500, 20, 10);
 
       const result = stats.formatCompact('Test task', baseTime + 5000);
 
       expect(result).toContain('📋 Task Completed: Test task');
       expect(result).toContain('🔧 Tool Usage: 1 calls, 100.0% success');
       expect(result).toContain('⏱️ Duration: 5.0s | 🔁 Rounds: 2');
-      expect(result).toContain('🔢 Tokens: 1,500 (in 1000, out 500)');
+      expect(result).toContain('🔢 Tokens: 1,530 (in 1000, out 500)');
     });
 
     it('should handle zero tool calls', () => {
diff --git a/packages/core/src/subagents/subagent-statistics.ts b/packages/core/src/subagents/subagent-statistics.ts
index 3ef120c6..72308c63 100644
--- a/packages/core/src/subagents/subagent-statistics.ts
+++ b/packages/core/src/subagents/subagent-statistics.ts
@@ -23,6 +23,8 @@ export interface SubagentStatsSummary {
   successRate: number;
   inputTokens: number;
   outputTokens: number;
+  thoughtTokens: number;
+  cachedTokens: number;
   totalTokens: number;
   estimatedCost: number;
   toolUsage: ToolUsageStats[];
@@ -36,6 +38,8 @@ export class SubagentStatistics {
   private failedToolCalls = 0;
   private inputTokens = 0;
   private outputTokens = 0;
+  private thoughtTokens = 0;
+  private cachedTokens = 0;
   private toolUsage = new Map<string, ToolUsageStats>();
 
   start(now = Date.now()) {
@@ -74,9 +78,16 @@ export class SubagentStatistics {
     this.toolUsage.set(name, tu);
   }
 
-  recordTokens(input: number, output: number) {
+  recordTokens(
+    input: number,
+    output: number,
+    thought: number = 0,
+    cached: number = 0,
+  ) {
     this.inputTokens += Math.max(0, input || 0);
     this.outputTokens += Math.max(0, output || 0);
+    this.thoughtTokens += Math.max(0, thought || 0);
+    this.cachedTokens += Math.max(0, cached || 0);
   }
 
   getSummary(now = Date.now()): SubagentStatsSummary {
@@ -86,7 +97,11 @@ export class SubagentStatistics {
       totalToolCalls > 0
         ? (this.successfulToolCalls / totalToolCalls) * 100
         : 0;
-    const totalTokens = this.inputTokens + this.outputTokens;
+    const totalTokens =
+      this.inputTokens +
+      this.outputTokens +
+      this.thoughtTokens +
+      this.cachedTokens;
     const estimatedCost = this.inputTokens * 3e-5 + this.outputTokens * 6e-5;
     return {
       rounds: this.rounds,
@@ -97,6 +112,8 @@ export class SubagentStatistics {
       successRate,
       inputTokens: this.inputTokens,
       outputTokens: this.outputTokens,
+      thoughtTokens: this.thoughtTokens,
+      cachedTokens: this.cachedTokens,
       totalTokens,
       estimatedCost,
       toolUsage: Array.from(this.toolUsage.values()),
@@ -116,8 +133,12 @@ export class SubagentStatistics {
       `⏱️ Duration: ${this.fmtDuration(stats.totalDurationMs)} | 🔁 Rounds: ${stats.rounds}`,
     ];
     if (typeof stats.totalTokens === 'number') {
+      const parts = [
+        `in ${stats.inputTokens ?? 0}`,
+        `out ${stats.outputTokens ?? 0}`,
+      ];
       lines.push(
-        `🔢 Tokens: ${stats.totalTokens.toLocaleString()}${stats.inputTokens || stats.outputTokens ? ` (in ${stats.inputTokens ?? 0}, out ${stats.outputTokens ?? 0})` : ''}`,
+        `🔢 Tokens: ${stats.totalTokens.toLocaleString()}${parts.length ? ` (${parts.join(', ')})` : ''}`,
       );
     }
     return lines.join('\n');
@@ -152,8 +173,12 @@ export class SubagentStatistics {
       `🔧 Tools: ${stats.totalToolCalls} calls, ${sr.toFixed(1)}% success (${stats.successfulToolCalls} ok, ${stats.failedToolCalls} failed)`,
     );
     if (typeof stats.totalTokens === 'number') {
+      const parts = [
+        `in ${stats.inputTokens ?? 0}`,
+        `out ${stats.outputTokens ?? 0}`,
+      ];
       lines.push(
-        `🔢 Tokens: ${stats.totalTokens.toLocaleString()} (in ${stats.inputTokens ?? 0}, out ${stats.outputTokens ?? 0})`,
+        `🔢 Tokens: ${stats.totalTokens.toLocaleString()} (${parts.join(', ')})`,
       );
     }
     if (stats.toolUsage && stats.toolUsage.length) {
diff --git a/packages/core/src/subagents/subagent.ts b/packages/core/src/subagents/subagent.ts
index 885e8ca6..39e43e54 100644
--- a/packages/core/src/subagents/subagent.ts
+++ b/packages/core/src/subagents/subagent.ts
@@ -41,6 +41,7 @@ import type {
   SubAgentToolResultEvent,
   SubAgentStreamTextEvent,
   SubAgentErrorEvent,
+  SubAgentUsageEvent,
 } from './subagent-events.js';
 import {
   type SubAgentEventEmitter,
@@ -369,6 +370,7 @@ export class SubAgentScope {
           },
         };
 
+        const roundStreamStart = Date.now();
         const responseStream = await chat.sendMessageStream(
           this.modelConfig.model ||
             this.runtimeContext.getModel() ||
@@ -439,10 +441,19 @@ export class SubAgentScope {
         if (lastUsage) {
           const inTok = Number(lastUsage.promptTokenCount || 0);
           const outTok = Number(lastUsage.candidatesTokenCount || 0);
-          if (isFinite(inTok) || isFinite(outTok)) {
+          const thoughtTok = Number(lastUsage.thoughtsTokenCount || 0);
+          const cachedTok = Number(lastUsage.cachedContentTokenCount || 0);
+          if (
+            isFinite(inTok) ||
+            isFinite(outTok) ||
+            isFinite(thoughtTok) ||
+            isFinite(cachedTok)
+          ) {
             this.stats.recordTokens(
               isFinite(inTok) ? inTok : 0,
               isFinite(outTok) ? outTok : 0,
+              isFinite(thoughtTok) ? thoughtTok : 0,
+              isFinite(cachedTok) ? cachedTok : 0,
             );
             // mirror legacy fields for compatibility
             this.executionStats.inputTokens =
@@ -453,11 +464,20 @@ export class SubAgentScope {
               (isFinite(outTok) ? outTok : 0);
             this.executionStats.totalTokens =
               (this.executionStats.inputTokens || 0) +
-              (this.executionStats.outputTokens || 0);
+              (this.executionStats.outputTokens || 0) +
+              (isFinite(thoughtTok) ? thoughtTok : 0) +
+              (isFinite(cachedTok) ? cachedTok : 0);
             this.executionStats.estimatedCost =
               (this.executionStats.inputTokens || 0) * 3e-5 +
               (this.executionStats.outputTokens || 0) * 6e-5;
           }
+          this.eventEmitter?.emit(SubAgentEventType.USAGE_METADATA, {
+            subagentId: this.subagentId,
+            round: turnCounter,
+            usage: lastUsage,
+            durationMs: Date.now() - roundStreamStart,
+            timestamp: Date.now(),
+          } as SubAgentUsageEvent);
         }
 
         if (functionCalls.length > 0) {
diff --git a/packages/core/src/telemetry/uiTelemetry.ts b/packages/core/src/telemetry/uiTelemetry.ts
index 9a257e5a..0f8f2146 100644
--- a/packages/core/src/telemetry/uiTelemetry.ts
+++ b/packages/core/src/telemetry/uiTelemetry.ts
@@ -23,6 +23,12 @@ export type UiEvent =
   | (ApiErrorEvent & { 'event.name': typeof EVENT_API_ERROR })
   | (ToolCallEvent & { 'event.name': typeof EVENT_TOOL_CALL });
 
+export {
+  EVENT_API_ERROR,
+  EVENT_API_RESPONSE,
+  EVENT_TOOL_CALL,
+} from './constants.js';
+
 export interface ToolCallStats {
   count: number;
   success: number;