feat(sessions): add resuming to geminiChat and add CLI flags for session management

packages/cli/src/config/config.test.ts

@@ -451,6 +451,36 @@ describe('parseArguments', () => {
     mockConsoleError.mockRestore();
   });
 
+  it('should throw an error when resuming a session without prompt in non-interactive mode', async () => {
+    const originalIsTTY = process.stdin.isTTY;
+    process.stdin.isTTY = false;
+    process.argv = ['node', 'script.js', '--resume', 'session-id'];
+
+    const mockExit = vi.spyOn(process, 'exit').mockImplementation(() => {
+      throw new Error('process.exit called');
+    });
+
+    const mockConsoleError = vi
+      .spyOn(console, 'error')
+      .mockImplementation(() => {});
+
+    try {
+      await expect(parseArguments({} as Settings)).rejects.toThrow(
+        'process.exit called',
+      );
+
+      expect(mockConsoleError).toHaveBeenCalledWith(
+        expect.stringContaining(
+          'When resuming a session, you must provide a message via --prompt (-p) or stdin',
+        ),
+      );
+    } finally {
+      mockExit.mockRestore();
+      mockConsoleError.mockRestore();
+      process.stdin.isTTY = originalIsTTY;
+    }
+  });
+
   it('should support comma-separated values for --allowed-tools', async () => {
     process.argv = [
       'node',

packages/cli/src/config/config.ts

@@ -61,6 +61,9 @@ export interface CliArgs {
   experimentalAcp: boolean | undefined;
   extensions: string[] | undefined;
   listExtensions: boolean | undefined;
+  resume: string | 'latest' | undefined;
+  listSessions: boolean | undefined;
+  deleteSession: string | undefined;
   includeDirectories: string[] | undefined;
   screenReader: boolean | undefined;
   useSmartEdit: boolean | undefined;
@@ -172,6 +175,35 @@ export async function parseArguments(settings: Settings): Promise<CliArgs> {
           type: 'boolean',
           description: 'List all available extensions and exit.',
         })
+        .option('resume', {
+          alias: 'r',
+          type: 'string',
+          // `skipValidation` so that we can distinguish between it being passed with a value, without
+          // one, and not being passed at all.
+          skipValidation: true,
+          description:
+            'Resume a previous session. Use "latest" for most recent or index number (e.g. --resume 5)',
+          coerce: (value: string): string => {
+            // When --resume passed with a value (`gemini --resume 123`): value = "123" (string)
+            // When --resume passed without a value (`gemini --resume`): value = "" (string)
+            // When --resume not passed at all: this `coerce` function is not called at all, and
+            //   `yargsInstance.argv.resume` is undefined.
+            if (value === '') {
+              return 'latest';
+            }
+            return value;
+          },
+        })
+        .option('list-sessions', {
+          type: 'boolean',
+          description:
+            'List available sessions for the current project and exit.',
+        })
+        .option('delete-session', {
+          type: 'string',
+          description:
+            'Delete a session by index number (use --list-sessions to see available sessions).',
+        })
         .option('include-directories', {
           type: 'array',
           string: true,
@@ -227,6 +259,11 @@ export async function parseArguments(settings: Settings): Promise<CliArgs> {
           if (argv['prompt'] && argv['promptInteractive']) {
             return 'Cannot use both --prompt (-p) and --prompt-interactive (-i) together';
           }
+          if (argv.resume && !argv.prompt && !process.stdin.isTTY) {
+            throw new Error(
+              'When resuming a session, you must provide a message via --prompt (-p) or stdin',
+            );
+          }
           if (argv.yolo && argv['approvalMode']) {
             return 'Cannot use both --yolo (-y) and --approval-mode together. Use --approval-mode=yolo instead.';
           }
@@ -585,6 +622,8 @@ export async function loadCliConfig(
     maxSessionTurns: settings.model?.maxSessionTurns ?? -1,
     experimentalZedIntegration: argv.experimentalAcp || false,
     listExtensions: argv.listExtensions || false,
+    listSessions: argv.listSessions || false,
+    deleteSession: argv.deleteSession,
     enabledExtensions: argv.extensions,
     extensionLoader: extensionManager,
     enableExtensionReloading: settings.experimental?.extensionReloading,

packages/cli/src/gemini.test.tsx

@@ -21,7 +21,7 @@ import {
 } from './gemini.js';
 import { type LoadedSettings } from './config/settings.js';
 import { appEvents, AppEvent } from './utils/events.js';
-import { type Config } from '@google/gemini-cli-core';
+import { type Config, type ResumedSessionData } from '@google/gemini-cli-core';
 import { act } from 'react';
 import { type InitializationResult } from './core/initializer.js';
 
@@ -189,6 +189,8 @@ describe('gemini.tsx main function', () => {
         getSandbox: () => false,
         getDebugMode: () => false,
         getListExtensions: () => false,
+        getListSessions: () => false,
+        getDeleteSession: () => undefined,
         getMcpServers: () => ({}),
         getMcpClientManager: vi.fn(),
         initialize: vi.fn(),
@@ -339,6 +341,8 @@ describe('gemini.tsx main function kitty protocol', () => {
       getSandbox: () => false,
       getDebugMode: () => false,
       getListExtensions: () => false,
+      getListSessions: () => false,
+      getDeleteSession: () => undefined,
       getMcpServers: () => ({}),
       getMcpClientManager: vi.fn(),
       initialize: vi.fn(),
@@ -391,6 +395,9 @@ describe('gemini.tsx main function kitty protocol', () => {
       screenReader: undefined,
       useSmartEdit: undefined,
       useWriteTodos: undefined,
+      resume: undefined,
+      listSessions: undefined,
+      deleteSession: undefined,
       outputFormat: undefined,
       fakeResponses: undefined,
       recordResponses: undefined,
@@ -488,6 +495,7 @@ describe('startInteractiveUI', () => {
     settings: LoadedSettings,
     startupWarnings: string[],
     workspaceRoot: string,
+    resumedSessionData: ResumedSessionData | undefined,
     initializationResult: InitializationResult,
   ) {
     await act(async () => {
@@ -496,6 +504,7 @@ describe('startInteractiveUI', () => {
         settings,
         startupWarnings,
         workspaceRoot,
+        resumedSessionData,
         initializationResult,
       );
     });
@@ -510,6 +519,7 @@ describe('startInteractiveUI', () => {
       mockSettings,
       mockStartupWarnings,
       mockWorkspaceRoot,
+      undefined,
       mockInitializationResult,
     );
 
@@ -538,6 +548,7 @@ describe('startInteractiveUI', () => {
       mockSettings,
       mockStartupWarnings,
       mockWorkspaceRoot,
+      undefined,
       mockInitializationResult,
     );
 
@@ -563,6 +574,7 @@ describe('startInteractiveUI', () => {
       mockSettings,
       mockStartupWarnings,
       mockWorkspaceRoot,
+      undefined,
       mockInitializationResult,
     );
 
@@ -579,6 +591,7 @@ describe('startInteractiveUI', () => {
       mockSettings,
       mockStartupWarnings,
       mockWorkspaceRoot,
+      undefined,
       mockInitializationResult,
     );
 
@@ -610,6 +623,7 @@ describe('startInteractiveUI', () => {
       mockSettings,
       mockStartupWarnings,
       mockWorkspaceRoot,
+      undefined,
       mockInitializationResult,
     );
 

packages/cli/src/gemini.tsx

@@ -32,7 +32,7 @@ import {
   runExitCleanup,
 } from './utils/cleanup.js';
 import { getCliVersion } from './utils/version.js';
-import { type Config } from '@google/gemini-cli-core';
+import type { Config, ResumedSessionData } from '@google/gemini-cli-core';
 import {
   sessionId,
   logUserPrompt,
@@ -55,6 +55,7 @@ import { detectAndEnableKittyProtocol } from './ui/utils/kittyProtocolDetector.j
 import { checkForUpdates } from './ui/utils/updateCheck.js';
 import { handleAutoUpdate } from './utils/handleAutoUpdate.js';
 import { appEvents, AppEvent } from './utils/events.js';
+import { SessionSelector } from './utils/sessionUtils.js';
 import { computeWindowTitle } from './utils/windowTitle.js';
 import { SettingsContext } from './ui/contexts/SettingsContext.js';
 import { MouseProvider } from './ui/contexts/MouseContext.js';
@@ -68,6 +69,7 @@ import {
   relaunchOnExitCode,
 } from './utils/relaunch.js';
 import { loadSandboxConfig } from './config/sandboxConfig.js';
+import { deleteSession, listSessions } from './utils/sessions.js';
 import { ExtensionManager } from './config/extension-manager.js';
 import { createPolicyUpdater } from './config/policy.js';
 import { requestConsentNonInteractive } from './config/extensions/consent.js';
@@ -151,6 +153,7 @@ export async function startInteractiveUI(
   settings: LoadedSettings,
   startupWarnings: string[],
   workspaceRoot: string = process.cwd(),
+  resumedSessionData: ResumedSessionData | undefined,
   initializationResult: InitializationResult,
 ) {
   // When not in screen reader mode, disable line wrapping.
@@ -205,6 +208,7 @@ export async function startInteractiveUI(
                     settings={settings}
                     startupWarnings={startupWarnings}
                     version={version}
+                    resumedSessionData={resumedSessionData}
                     initializationResult={initializationResult}
                   />
                 </VimModeProvider>
@@ -414,6 +418,19 @@ export async function main() {
       process.exit(0);
     }
 
+    // Handle --list-sessions flag
+    if (config.getListSessions()) {
+      await listSessions(config);
+      process.exit(0);
+    }
+
+    // Handle --delete-session flag
+    const sessionToDelete = config.getDeleteSession();
+    if (sessionToDelete) {
+      await deleteSession(config, sessionToDelete);
+      process.exit(0);
+    }
+
     const wasRaw = process.stdin.isRaw;
     if (config.isInteractive() && !wasRaw && process.stdin.isTTY) {
       // Set this as early as possible to avoid spurious characters from
@@ -454,13 +471,34 @@ export async function main() {
       ...(await getUserStartupWarnings()),
     ];
 
+    // Handle --resume flag
+    let resumedSessionData: ResumedSessionData | undefined = undefined;
+    if (argv.resume) {
+      const sessionSelector = new SessionSelector(config);
+      try {
+        const result = await sessionSelector.resolveSession(argv.resume);
+        resumedSessionData = {
+          conversation: result.sessionData,
+          filePath: result.sessionPath,
+        };
+        // Use the existing session ID to continue recording to the same session
+        config.setSessionId(resumedSessionData.conversation.sessionId);
+      } catch (error) {
+        console.error(
+          `Error resuming session: ${error instanceof Error ? error.message : 'Unknown error'}`,
+        );
+        process.exit(1);
+      }
+    }
+
     // Render UI, passing necessary config values. Check that there is no command line question.
     if (config.isInteractive()) {
       await startInteractiveUI(
         config,
         settings,
         startupWarnings,
         process.cwd(),
+        resumedSessionData,
         initializationResult,
       );
       return;
@@ -514,6 +552,7 @@ export async function main() {
       input,
       prompt_id,
       hasDeprecatedPromptArg,
+      resumedSessionData,
     });
     // Call cleanup before process.exit, which causes cleanup to not run
     await runExitCleanup();

packages/cli/src/nonInteractiveCli.test.ts

@@ -93,6 +93,7 @@ describe('runNonInteractive', () => {
   let processStderrSpy: MockInstance;
   let mockGeminiClient: {
     sendMessageStream: Mock;
+    resumeChat: Mock;
     getChatRecordingService: Mock;
   };
   const MOCK_SESSION_METRICS: SessionMetrics = {
@@ -142,6 +143,7 @@ describe('runNonInteractive', () => {
 
     mockGeminiClient = {
       sendMessageStream: vi.fn(),
+      resumeChat: vi.fn().mockResolvedValue(undefined),
       getChatRecordingService: vi.fn(() => ({
         initialize: vi.fn(),
         recordMessage: vi.fn(),

packages/cli/src/nonInteractiveCli.ts

@@ -7,6 +7,7 @@
 import type {
   Config,
   ToolCallRequestInfo,
+  ResumedSessionData,
   CompletedToolCall,
   UserFeedbackPayload,
 } from '@google/gemini-cli-core';
@@ -32,6 +33,7 @@ import {
 import type { Content, Part } from '@google/genai';
 import readline from 'node:readline';
 
+import { convertSessionToHistoryFormats } from './ui/hooks/useSessionBrowser.js';
 import { handleSlashCommand } from './nonInteractiveCliCommands.js';
 import { ConsolePatcher } from './ui/utils/ConsolePatcher.js';
 import { handleAtCommand } from './ui/hooks/atCommandProcessor.js';
@@ -49,6 +51,7 @@ interface RunNonInteractiveParams {
   input: string;
   prompt_id: string;
   hasDeprecatedPromptArg?: boolean;
+  resumedSessionData?: ResumedSessionData;
 }
 
 export async function runNonInteractive({
@@ -57,6 +60,7 @@ export async function runNonInteractive({
   input,
   prompt_id,
   hasDeprecatedPromptArg,
+  resumedSessionData,
 }: RunNonInteractiveParams): Promise<void> {
   return promptIdContext.run(prompt_id, async () => {
     const consolePatcher = new ConsolePatcher({
@@ -185,6 +189,16 @@ export async function runNonInteractive({
 
       const geminiClient = config.getGeminiClient();
 
+      // Initialize chat.  Resume if resume data is passed.
+      if (resumedSessionData) {
+        await geminiClient.resumeChat(
+          convertSessionToHistoryFormats(
+            resumedSessionData.conversation.messages,
+          ).clientHistory,
+          resumedSessionData,
+        );
+      }
+
       // Emit init event for streaming JSON
       if (streamFormatter) {
         streamFormatter.emitEvent({