feat: foundation for subagent trajectories (Stage 1)

packages/cli/src/ui/commands/bugCommand.test.ts

@@ -173,6 +173,8 @@ describe('bugCommand', () => {
           geminiClient: {
             getChat: () => ({
               getHistory: () => history,
+              getSubagentTrajectories: vi.fn().mockResolvedValue({}),
+              getConversation: vi.fn().mockReturnValue({ messages: [] }),
             }),
           },
         },
@@ -187,8 +189,10 @@ describe('bugCommand', () => {
       'bug-report-history-1704067200000.json',
     );
     expect(exportHistoryToFile).toHaveBeenCalledWith({
-      history,
+      messages: [],
       filePath: expectedPath,
+      trajectories: {},
+      history,
     });
 
     const addItemCall = vi.mocked(mockContext.ui.addItem).mock.calls[0];

packages/cli/src/ui/commands/bugCommand.ts

@@ -88,7 +88,14 @@ export const bugCommand: SlashCommand = {
         const historyFileName = `bug-report-history-${Date.now()}.json`;
         const historyFilePath = path.join(tempDir, historyFileName);
         try {
-          await exportHistoryToFile({ history, filePath: historyFilePath });
+          const trajectories = await chat?.getSubagentTrajectories();
+          const messages = chat?.getConversation()?.messages ?? [];
+          await exportHistoryToFile({
+            messages,
+            filePath: historyFilePath,
+            trajectories,
+            history,
+          });
           historyFileMessage = `\n\n--------------------------------------------------------------------------------\n\n📄 **Chat History Exported**\nTo help us debug, we've exported your current chat history to:\n${historyFilePath}\n\nPlease consider attaching this file to your GitHub issue if you feel comfortable doing so.\n\n**Privacy Disclaimer:** Please do not upload any logs containing sensitive or private information that you are not comfortable sharing publicly.`;
           problemValue += `\n\n[ACTION REQUIRED] 📎 PLEASE ATTACH THE EXPORTED CHAT HISTORY JSON FILE TO THIS ISSUE IF YOU FEEL COMFORTABLE SHARING IT.`;
         } catch (err) {

packages/cli/src/ui/commands/chatCommand.test.ts

@@ -63,6 +63,8 @@ describe('chatCommand', () => {
     mockGetHistory = vi.fn().mockReturnValue([]);
     mockGetChat = vi.fn().mockReturnValue({
       getHistory: mockGetHistory,
+      getSubagentTrajectories: vi.fn().mockResolvedValue({}),
+      getConversation: vi.fn().mockReturnValue({ messages: [] }),
     });
     mockSaveCheckpoint = vi.fn().mockResolvedValue(undefined);
     mockLoadCheckpoint = vi.fn().mockResolvedValue({ history: [] });
@@ -191,6 +193,15 @@ describe('chatCommand', () => {
         { role: 'user', parts: [{ text: 'Hello, how are you?' }] },
       ]);
       result = await saveCommand?.action?.(mockContext, tag);
+      expect(mockSaveCheckpoint).toHaveBeenCalledWith(
+        {
+          history: expect.any(Array),
+          authType: AuthType.LOGIN_WITH_GOOGLE,
+          trajectories: {},
+          messages: [],
+        },
+        tag,
+      );
       expect(result).toEqual({
         type: 'message',
         messageType: 'info',
@@ -230,7 +241,12 @@ describe('chatCommand', () => {
 
       expect(mockCheckpointExists).not.toHaveBeenCalled(); // Should skip existence check
       expect(mockSaveCheckpoint).toHaveBeenCalledWith(
-        { history, authType: AuthType.LOGIN_WITH_GOOGLE },
+        {
+          history,
+          authType: AuthType.LOGIN_WITH_GOOGLE,
+          trajectories: {},
+          messages: [],
+        },
         tag,
       );
       expect(result).toEqual({
@@ -292,6 +308,8 @@ describe('chatCommand', () => {
           { type: 'gemini', text: 'hello world' },
         ] as HistoryItemWithoutId[],
         clientHistory: conversation,
+        messages: undefined,
+        version: undefined,
       });
     });
 
@@ -332,6 +350,8 @@ describe('chatCommand', () => {
           { type: 'gemini', text: 'hello world' },
         ] as HistoryItemWithoutId[],
         clientHistory: conversation,
+        messages: undefined,
+        version: undefined,
       });
     });
 
@@ -463,8 +483,10 @@ describe('chatCommand', () => {
         'gemini-conversation-1234567890.json',
       );
       expect(mockExport).toHaveBeenCalledWith({
-        history: mockHistory,
+        messages: [],
         filePath: expectedPath,
+        trajectories: {},
+        history: mockHistory,
       });
       expect(result).toEqual({
         type: 'message',
@@ -478,8 +500,10 @@ describe('chatCommand', () => {
       const result = await shareCommand?.action?.(mockContext, filePath);
       const expectedPath = path.join(process.cwd(), 'my-chat.json');
       expect(mockExport).toHaveBeenCalledWith({
-        history: mockHistory,
+        messages: [],
         filePath: expectedPath,
+        trajectories: {},
+        history: mockHistory,
       });
       expect(result).toEqual({
         type: 'message',
@@ -493,8 +517,10 @@ describe('chatCommand', () => {
       const result = await shareCommand?.action?.(mockContext, filePath);
       const expectedPath = path.join(process.cwd(), 'my-chat.md');
       expect(mockExport).toHaveBeenCalledWith({
-        history: mockHistory,
+        messages: [],
         filePath: expectedPath,
+        trajectories: {},
+        history: mockHistory,
       });
       expect(result).toEqual({
         type: 'message',
@@ -543,8 +569,10 @@ describe('chatCommand', () => {
       await shareCommand?.action?.(mockContext, filePath);
       const expectedPath = path.join(process.cwd(), 'my-chat.json');
       expect(mockExport).toHaveBeenCalledWith({
-        history: mockHistory,
+        messages: [],
         filePath: expectedPath,
+        trajectories: {},
+        history: mockHistory,
       });
     });
 
@@ -553,8 +581,10 @@ describe('chatCommand', () => {
       await shareCommand?.action?.(mockContext, filePath);
       const expectedPath = path.join(process.cwd(), 'my-chat.md');
       expect(mockExport).toHaveBeenCalledWith({
-        history: mockHistory,
+        messages: [],
         filePath: expectedPath,
+        trajectories: {},
+        history: mockHistory,
       });
     });
   });

packages/cli/src/ui/commands/chatCommand.ts

@@ -139,7 +139,12 @@ const saveCommand: SlashCommand = {
     const history = chat.getHistory();
     if (history.length > INITIAL_HISTORY_LENGTH) {
       const authType = config?.getContentGeneratorConfig()?.authType;
-      await logger.saveCheckpoint({ history, authType }, tag);
+      const trajectories = await chat.getSubagentTrajectories();
+      const messages = chat.getConversation()?.messages ?? [];
+      await logger.saveCheckpoint(
+        { history, authType, trajectories, messages },
+        tag,
+      );
       return {
         type: 'message',
         messageType: 'info',
@@ -324,7 +329,9 @@ const shareCommand: SlashCommand = {
     }
 
     try {
-      await exportHistoryToFile({ history, filePath });
+      const trajectories = await chat.getSubagentTrajectories();
+      const messages = chat.getConversation()?.messages ?? [];
+      await exportHistoryToFile({ messages, filePath, trajectories, history });
       return {
         type: 'message',
         messageType: 'info',

packages/cli/src/ui/utils/historyExportUtils.ts

@@ -7,6 +7,11 @@
 import * as fsPromises from 'node:fs/promises';
 import path from 'node:path';
 import type { Content } from '@google/genai';
+import {
+  type ConversationRecord,
+  type MessageRecord,
+  reconstructHistory,
+} from '@google/gemini-cli-core';
 
 /**
  * Serializes chat history to a Markdown string.
@@ -51,8 +56,20 @@ export function serializeHistoryToMarkdown(
  * Options for exporting chat history.
  */
 export interface ExportHistoryOptions {
-  history: readonly Content[];
+  /**
+   * Optional full message records which contain metadata like agentId for tool calls,
+   * providing the link between history and trajectories.
+   */
+  messages?: MessageRecord[];
+  /** The file path to export to. */
   filePath: string;
+  /** Optional subagent trajectories to include. */
+  trajectories?: Record<string, ConversationRecord>;
+  /**
+   * Optional standard history array used for model requests.
+   * If provided, it is used for Markdown export to avoid reconstruction.
+   */
+  history?: readonly Content[];
 }
 
 /**
@@ -61,13 +78,21 @@ export interface ExportHistoryOptions {
 export async function exportHistoryToFile(
   options: ExportHistoryOptions,
 ): Promise<void> {
-  const { history, filePath } = options;
+  const {
+    messages,
+    filePath,
+    trajectories: _trajectories, // Collected but not yet included in Stage 1 JSON output
+    history: providedHistory,
+  } = options;
   const extension = path.extname(filePath).toLowerCase();
 
   let content: string;
   if (extension === '.json') {
-    content = JSON.stringify(history, null, 2);
+    // Stage 1 & 2: Maintain legacy behavior - only export the raw history array.
+    // Trajectories and messages are collected but not yet included in Stage 2 JSON output.
+    content = JSON.stringify(providedHistory ?? [], null, 2);
   } else if (extension === '.md') {
+    const history = providedHistory ?? reconstructHistory(messages ?? []);
     content = serializeHistoryToMarkdown(history);
   } else {
     throw new Error(