diff --git a/src/auth/google.ts b/src/auth/google.ts
new file mode 100644
index 0000000..ce5eec2
--- /dev/null
+++ b/src/auth/google.ts
@@ -0,0 +1,136 @@
+import { readFileSync, writeFileSync, mkdirSync, chmodSync } from 'fs';
+import { resolve } from 'path';
+import { homedir } from 'os';
+
+export type GoogleService = 'gmail' | 'gcal' | 'gdocs' | 'gdrive' | 'gtasks';
+
+const AUTH_DIR = resolve(homedir(), '.config/flynn');
+const AUTH_FILE = resolve(AUTH_DIR, 'auth.json');
+
+export interface GoogleTokenRecord {
+  token: Record<string, unknown>;
+  scopes?: string[];
+  token_file?: string;
+  credentials_file?: string;
+  updated_at: string;
+}
+
+export interface GoogleAuthInfo {
+  services: Partial<Record<GoogleService, GoogleTokenRecord>>;
+}
+
+interface AuthStore {
+  google?: GoogleAuthInfo;
+  [key: string]: unknown;
+}
+
+function isIgnorableStoreError(error: unknown): boolean {
+  if (!(error instanceof Error) || !('code' in error)) {
+    return false;
+  }
+  const code = (error as NodeJS.ErrnoException).code;
+  return code === 'EACCES' || code === 'EPERM' || code === 'EROFS';
+}
+
+function safeJsonParse<T>(raw: string): T | null {
+  try {
+    return JSON.parse(raw) as T;
+  } catch {
+    return null;
+  }
+}
+
+function readAuthStore(): AuthStore {
+  try {
+    const raw = readFileSync(AUTH_FILE, 'utf-8');
+    const parsed = safeJsonParse<AuthStore>(raw);
+    return parsed ?? {};
+  } catch {
+    return {};
+  }
+}
+
+function writeAuthStore(store: AuthStore): void {
+  mkdirSync(AUTH_DIR, { recursive: true });
+  writeFileSync(AUTH_FILE, JSON.stringify(store, null, 2) + '\n', 'utf-8');
+  chmodSync(AUTH_FILE, 0o600);
+}
+
+function parseScopes(token: Record<string, unknown>, explicitScopes?: string[]): string[] | undefined {
+  if (explicitScopes && explicitScopes.length > 0) {
+    return explicitScopes;
+  }
+  const scopeValue = token.scope;
+  if (typeof scopeValue !== 'string' || scopeValue.trim().length === 0) {
+    return undefined;
+  }
+  return scopeValue.split(/\s+/).filter(Boolean);
+}
+
+function ensureGoogleAuth(store: AuthStore): GoogleAuthInfo {
+  if (!store.google) {
+    store.google = { services: {} };
+    return store.google;
+  }
+  if (!store.google.services) {
+    store.google.services = {};
+  }
+  return store.google;
+}
+
+export function loadStoredGoogleTokenRecord(service: GoogleService): GoogleTokenRecord | null {
+  const store = readAuthStore();
+  return store.google?.services?.[service] ?? null;
+}
+
+export function loadStoredGoogleToken(service: GoogleService): Record<string, unknown> | null {
+  return loadStoredGoogleTokenRecord(service)?.token ?? null;
+}
+
+export function storeGoogleToken(
+  service: GoogleService,
+  token: Record<string, unknown>,
+  options?: {
+    scopes?: string[];
+    tokenFile?: string;
+    credentialsFile?: string;
+  },
+): void {
+  const store = readAuthStore();
+  const google = ensureGoogleAuth(store);
+  google.services[service] = {
+    token,
+    scopes: parseScopes(token, options?.scopes),
+    token_file: options?.tokenFile,
+    credentials_file: options?.credentialsFile,
+    updated_at: new Date().toISOString(),
+  };
+  try {
+    writeAuthStore(store);
+  } catch (error) {
+    // Preserve legacy token-file behavior when central store cannot be written.
+    if (!isIgnorableStoreError(error)) {
+      throw error;
+    }
+  }
+}
+
+export function clearGoogleToken(service: GoogleService): void {
+  const store = readAuthStore();
+  if (!store.google?.services?.[service]) {
+    return;
+  }
+
+  delete store.google.services[service];
+
+  if (Object.keys(store.google.services).length === 0) {
+    delete store.google;
+  }
+  try {
+    writeAuthStore(store);
+  } catch (error) {
+    if (!isIgnorableStoreError(error)) {
+      throw error;
+    }
+  }
+}
diff --git a/src/auth/index.ts b/src/auth/index.ts
index 44ddf5f..c2f87b3 100644
--- a/src/auth/index.ts
+++ b/src/auth/index.ts
@@ -53,3 +53,13 @@ export {
   getZaiApiKey,
   type ZaiAuthInfo,
 } from './zai.js';
+
+export {
+  loadStoredGoogleTokenRecord,
+  loadStoredGoogleToken,
+  storeGoogleToken,
+  clearGoogleToken,
+  type GoogleService,
+  type GoogleTokenRecord,
+  type GoogleAuthInfo,
+} from './google.js';
diff --git a/src/automation/gmail.ts b/src/automation/gmail.ts
index 90ddb75..cb674b9 100644
--- a/src/automation/gmail.ts
+++ b/src/automation/gmail.ts
@@ -1,13 +1,12 @@
 import { google, type Auth } from 'googleapis';
-import { readFileSync, writeFileSync, existsSync, mkdirSync, chmodSync } from 'fs';
-import { dirname, resolve } from 'path';
-import { homedir } from 'os';
+import { readFileSync, existsSync } from 'fs';
 import type { v1 } from '@google-cloud/pubsub';
 import type { GmailConfig } from '../config/schema.js';
 import type { ChannelAdapter, ChannelStatus, InboundMessage, OutboundMessage } from '../channels/types.js';
 import { parseInterval } from './heartbeat.js';
 import { sanitizeHtml } from '../utils/html.js';
 import { auditLogger } from '../audit/index.js';
+import { createGoogleOAuth2Client, expandPath } from '../google/oauth.js';
 
 /** Minimal interface for the parts of ChannelRegistry we need. */
 interface ChannelLookup {
@@ -178,6 +177,13 @@ export class GmailWatcher implements ChannelAdapter {
     this.messageHandler = handler;
   }
 
+  /**
+   * Backward-compatible path helper used by tests and callers.
+   */
+  expandPath(p: string): string {
+    return expandPath(p);
+  }
+
   /**
    * Handle a Pub/Sub push notification from Google.
    * Called by the gateway when POST /gmail/push is received.
@@ -218,45 +224,22 @@ export class GmailWatcher implements ChannelAdapter {
       throw new Error('No credentials_file configured. Set automation.gmail.credentials_file in config.');
     }
 
-    const expandedCredsPath = this.expandPath(credentialsPath);
+    const expandedCredsPath = expandPath(credentialsPath);
     if (!existsSync(expandedCredsPath)) {
       throw new Error(`Credentials file not found: ${expandedCredsPath}`);
     }
 
     const credentials = JSON.parse(readFileSync(expandedCredsPath, 'utf-8'));
-    const { client_id, client_secret, redirect_uris, project_id } = credentials.installed ?? credentials.web ?? {};
+    const { project_id } = credentials.installed ?? credentials.web ?? {};
     if (project_id && typeof project_id === 'string') {
       this.googleProjectId = project_id;
     }
 
-    if (!client_id || !client_secret) {
-      throw new Error('Invalid credentials file — missing client_id or client_secret');
-    }
-
-    const oauth2Client = new google.auth.OAuth2(
-      client_id,
-      client_secret,
-      redirect_uris?.[0] ?? 'http://localhost',
-    );
-
-    // Load stored token
-    const tokenPath = this.expandPath(this.config.token_file ?? '~/.config/flynn/gmail-token.json');
-    if (!existsSync(tokenPath)) {
-      throw new Error(
-        `Token file not found: ${tokenPath}. Run "flynn gmail-auth" to authenticate.`,
-      );
-    }
-
-    const token = JSON.parse(readFileSync(tokenPath, 'utf-8'));
-    oauth2Client.setCredentials(token);
-
-    // Auto-save refreshed tokens
-    oauth2Client.on('tokens', (newTokens) => {
-      const merged = { ...token, ...newTokens };
-      this.saveToken(merged);
+    return createGoogleOAuth2Client({
+      service: 'gmail',
+      credentialsFile: this.config.credentials_file,
+      tokenFile: this.config.token_file,
     });
-
-    return oauth2Client;
   }
 
   /**
@@ -608,30 +591,4 @@ export class GmailWatcher implements ChannelAdapter {
       .replace(/\{\{labels\}\}/g, email.labels.join(', '));
   }
 
-  /**
-   * Expand ~ to the user's home directory.
-   */
-  expandPath(p: string): string {
-    if (p.startsWith('~/') || p === '~') {
-      return resolve(homedir(), p.slice(2));
-    }
-    return resolve(p);
-  }
-
-  /**
-   * Save token to disk with restrictive permissions (0o600).
-   */
-  private saveToken(token: unknown): void {
-    const tokenPath = this.expandPath(this.config.token_file ?? '~/.config/flynn/gmail-token.json');
-    const dir = dirname(tokenPath);
-    if (!existsSync(dir)) {
-      mkdirSync(dir, { recursive: true });
-    }
-    writeFileSync(tokenPath, JSON.stringify(token, null, 2), 'utf-8');
-    try {
-      chmodSync(tokenPath, 0o600);
-    } catch {
-      // chmod may fail on some filesystems — not critical
-    }
-  }
 }
diff --git a/src/cli/doctor.test.ts b/src/cli/doctor.test.ts
index aa73622..9a3911c 100644
--- a/src/cli/doctor.test.ts
+++ b/src/cli/doctor.test.ts
@@ -6,8 +6,10 @@ import { tmpdir } from 'os';
 
 describe('doctor checks', () => {
   const testDir = join(tmpdir(), 'flynn-test-doctor');
+  const originalHome = process.env.HOME;
 
   afterEach(() => {
+    process.env.HOME = originalHome;
     try { rmSync(testDir, { recursive: true }); } catch {}
   });
 
@@ -201,6 +203,97 @@ automation:
     expect(gmailCheck?.detail).toContain('flynn gmail-auth');
   });
 
+  it('reports SKIP for Google Calendar when not enabled', async () => {
+    mkdirSync(testDir, { recursive: true });
+    const configPath = join(testDir, 'config.yaml');
+    writeFileSync(configPath, `
+telegram:
+  bot_token: "test-token"
+  allowed_chat_ids: [123]
+models:
+  default:
+    provider: anthropic
+    model: claude-sonnet
+`);
+
+    const ctx: DoctorContext = { configPath, dataDir: testDir };
+    const results = await runChecks(ctx);
+
+    const gcalCheck = results.find(r => r.label.includes('Google Calendar'));
+    expect(gcalCheck?.status).toBe('skip');
+  });
+
+  it('reports WARN for Google Calendar when token missing in file and auth store', async () => {
+    mkdirSync(testDir, { recursive: true });
+    const configPath = join(testDir, 'config.yaml');
+    const credsPath = join(testDir, 'gcal-creds.json');
+    writeFileSync(credsPath, '{}');
+    writeFileSync(configPath, `
+telegram:
+  bot_token: "test-token"
+  allowed_chat_ids: [123]
+models:
+  default:
+    provider: anthropic
+    model: claude-sonnet
+automation:
+  gcal:
+    enabled: true
+    credentials_file: "${credsPath}"
+    token_file: "${join(testDir, 'missing-gcal-token.json')}"
+`);
+
+    const ctx: DoctorContext = { configPath, dataDir: testDir };
+    const results = await runChecks(ctx);
+
+    const gcalCheck = results.find(r => r.label.includes('Google Calendar configured'));
+    expect(gcalCheck?.status).toBe('warn');
+    expect(gcalCheck?.detail).toContain('flynn gcal-auth');
+  });
+
+  it('reports PASS for Google Calendar when token exists in auth store', async () => {
+    mkdirSync(testDir, { recursive: true });
+    process.env.HOME = testDir;
+    const configPath = join(testDir, 'config.yaml');
+    const credsPath = join(testDir, 'gcal-creds.json');
+    writeFileSync(credsPath, '{}');
+    mkdirSync(join(testDir, '.config/flynn'), { recursive: true });
+    writeFileSync(
+      join(testDir, '.config/flynn/auth.json'),
+      JSON.stringify({
+        google: {
+          services: {
+            gcal: {
+              token: { refresh_token: 'refresh-test' },
+              updated_at: '2026-02-24T00:00:00.000Z',
+            },
+          },
+        },
+      }),
+    );
+    writeFileSync(configPath, `
+telegram:
+  bot_token: "test-token"
+  allowed_chat_ids: [123]
+models:
+  default:
+    provider: anthropic
+    model: claude-sonnet
+automation:
+  gcal:
+    enabled: true
+    credentials_file: "${credsPath}"
+    token_file: "${join(testDir, 'missing-gcal-token.json')}"
+`);
+
+    const ctx: DoctorContext = { configPath, dataDir: testDir };
+    const results = await runChecks(ctx);
+
+    const gcalCheck = results.find(r => r.label.includes('Google Calendar configured'));
+    expect(gcalCheck?.status).toBe('pass');
+    expect(gcalCheck?.detail).toContain('auth_store');
+  });
+
   it('reports PASS for Gmail when enabled (poll only)', async () => {
     mkdirSync(testDir, { recursive: true });
     const configPath = join(testDir, 'config.yaml');
diff --git a/src/cli/doctor.ts b/src/cli/doctor.ts
index 1e13d48..e49ed4c 100644
--- a/src/cli/doctor.ts
+++ b/src/cli/doctor.ts
@@ -31,6 +31,29 @@ const asRecord = (value: unknown): UnknownRecord | undefined => (
   value && typeof value === 'object' ? value as UnknownRecord : undefined
 );
 
+function loadAuthStore(): Record<string, unknown> {
+  const home = process.env.HOME ?? homedir();
+  const authFile = resolve(home, '.config/flynn/auth.json');
+  try {
+    const raw = readFileSync(authFile, 'utf-8');
+    const parsed = JSON.parse(raw) as unknown;
+    return (parsed && typeof parsed === 'object') ? parsed as Record<string, unknown> : {};
+  } catch {
+    return {};
+  }
+}
+
+function hasGoogleServiceToken(store: Record<string, unknown>, service: 'gmail' | 'gcal' | 'gdocs' | 'gdrive' | 'gtasks'): boolean {
+  const google = asRecord(store.google);
+  const services = asRecord(google?.services);
+  const record = asRecord(services?.[service]);
+  const token = asRecord(record?.token);
+  return Boolean(
+    (typeof token?.refresh_token === 'string' && token.refresh_token.length > 0)
+    || (typeof token?.access_token === 'string' && token.access_token.length > 0),
+  );
+}
+
 const checkConfigExists: Check = async (ctx) => {
   if (existsSync(ctx.configPath)) {
     return { status: 'pass', label: 'Config file exists', detail: `(${ctx.configPath})` };
@@ -184,18 +207,6 @@ const checkModelConnectivity: Check = async (ctx) => {
     return 'auto';
   };
 
-  const loadAuthStore = (): Record<string, unknown> => {
-    const home = process.env.HOME ?? homedir();
-    const authFile = resolve(home, '.config/flynn/auth.json');
-    try {
-      const raw = readFileSync(authFile, 'utf-8');
-      const parsed = JSON.parse(raw) as unknown;
-      return (parsed && typeof parsed === 'object') ? parsed as Record<string, unknown> : {};
-    } catch {
-      return {};
-    }
-  };
-
   const store = loadAuthStore();
 
   const storeOpenAIOAuthPresent = (): boolean => {
@@ -551,7 +562,10 @@ const checkGmail: Check = async (ctx) => {
   }
 
   const tokenPath = expandPath(gmail.token_file ?? '~/.config/flynn/gmail-token.json');
-  if (!existsSync(tokenPath)) {
+  const store = loadAuthStore();
+  const hasStoreToken = hasGoogleServiceToken(store, 'gmail');
+  const hasTokenFile = existsSync(tokenPath);
+  if (!hasTokenFile && !hasStoreToken) {
     return { status: 'warn', label: 'Gmail configured', detail: 'run `flynn gmail-auth` to authenticate' };
   }
 
@@ -592,12 +606,96 @@ const checkGmail: Check = async (ctx) => {
   }
 
   modes.push('poll');
-  const detail = `(${modes.join(' + ')} -> ${gmail.output.channel}/${gmail.output.peer})`;
+  const tokenSources: string[] = [];
+  if (hasTokenFile) {tokenSources.push('token_file');}
+  if (hasStoreToken) {tokenSources.push('auth_store');}
+  const detail = `(${modes.join(' + ')} -> ${gmail.output.channel}/${gmail.output.peer}; token=${tokenSources.join('+')})`;
   const withWarnings = warnings.length > 0 ? `${detail} — ${warnings.join('; ')}` : detail;
 
   return { status: warnings.length > 0 ? 'warn' : 'pass', label: 'Gmail configured', detail: withWarnings };
 };
 
+function checkGoogleAutomationService(
+  ctx: DoctorContext,
+  opts: {
+    service: 'gcal' | 'gdocs' | 'gdrive' | 'gtasks';
+    label: string;
+    authCommand: string;
+    credentialsFile?: string;
+    tokenFile?: string;
+    enabled?: boolean;
+  },
+): CheckResult {
+  if (!ctx.config) {
+    return { status: 'skip', label: opts.label, detail: '(config invalid)' };
+  }
+  if (!opts.enabled) {
+    return { status: 'skip', label: opts.label, detail: '(not enabled)' };
+  }
+
+  const credentialsPath = expandPath(opts.credentialsFile ?? `~/.config/flynn/${opts.service}-credentials.json`);
+  if (!existsSync(credentialsPath)) {
+    return { status: 'fail', label: opts.label, detail: `credentials file not found: ${credentialsPath}` };
+  }
+
+  const tokenPath = expandPath(opts.tokenFile ?? `~/.config/flynn/${opts.service}-token.json`);
+  const hasTokenFile = existsSync(tokenPath);
+  const store = loadAuthStore();
+  const hasStoreToken = hasGoogleServiceToken(store, opts.service);
+  if (!hasTokenFile && !hasStoreToken) {
+    return {
+      status: 'warn',
+      label: opts.label,
+      detail: `run \`flynn ${opts.authCommand}\` to authenticate`,
+    };
+  }
+
+  const tokenSources: string[] = [];
+  if (hasTokenFile) {tokenSources.push('token_file');}
+  if (hasStoreToken) {tokenSources.push('auth_store');}
+  return {
+    status: 'pass',
+    label: opts.label,
+    detail: `(token=${tokenSources.join('+')})`,
+  };
+}
+
+const checkGcal: Check = async (ctx) => checkGoogleAutomationService(ctx, {
+  service: 'gcal',
+  label: 'Google Calendar configured',
+  authCommand: 'gcal-auth',
+  enabled: ctx.config?.automation.gcal?.enabled,
+  credentialsFile: ctx.config?.automation.gcal?.credentials_file,
+  tokenFile: ctx.config?.automation.gcal?.token_file,
+});
+
+const checkGdocs: Check = async (ctx) => checkGoogleAutomationService(ctx, {
+  service: 'gdocs',
+  label: 'Google Docs configured',
+  authCommand: 'gdocs-auth',
+  enabled: ctx.config?.automation.gdocs?.enabled,
+  credentialsFile: ctx.config?.automation.gdocs?.credentials_file,
+  tokenFile: ctx.config?.automation.gdocs?.token_file,
+});
+
+const checkGdrive: Check = async (ctx) => checkGoogleAutomationService(ctx, {
+  service: 'gdrive',
+  label: 'Google Drive configured',
+  authCommand: 'gdrive-auth',
+  enabled: ctx.config?.automation.gdrive?.enabled,
+  credentialsFile: ctx.config?.automation.gdrive?.credentials_file,
+  tokenFile: ctx.config?.automation.gdrive?.token_file,
+});
+
+const checkGtasks: Check = async (ctx) => checkGoogleAutomationService(ctx, {
+  service: 'gtasks',
+  label: 'Google Tasks configured',
+  authCommand: 'gtasks-auth',
+  enabled: ctx.config?.automation.gtasks?.enabled,
+  credentialsFile: ctx.config?.automation.gtasks?.credentials_file,
+  tokenFile: ctx.config?.automation.gtasks?.token_file,
+});
+
 const checkMinioExtractors: Check = async (ctx) => {
   if (!ctx.config) {
     return { status: 'skip', label: 'MinIO ingest extractors', detail: '(config invalid)' };
@@ -634,6 +732,10 @@ const allChecks: Check[] = [
   checkModelConnectivity,
   checkTelegram,
   checkGmail,
+  checkGcal,
+  checkGdocs,
+  checkGdrive,
+  checkGtasks,
   checkMinioExtractors,
   checkMcpServers,
   checkSkills,
diff --git a/src/cli/gcal-auth.ts b/src/cli/gcal-auth.ts
index 7efcf95..5f011bd 100644
--- a/src/cli/gcal-auth.ts
+++ b/src/cli/gcal-auth.ts
@@ -5,6 +5,7 @@ import { homedir } from 'os';
 import { createServer, type Server } from 'http';
 import { URL } from 'url';
 import { loadConfigSafe } from './shared.js';
+import { storeGoogleToken } from '../auth/google.js';
 
 const SCOPES = ['https://www.googleapis.com/auth/calendar.readonly'];
 const REDIRECT_PORT = 3000;
@@ -90,6 +91,10 @@ function saveToken(tokenPath: string, token: unknown): void {
   } catch {
     // chmod may fail on some filesystems — not critical
   }
+
+  if (token && typeof token === 'object' && !Array.isArray(token)) {
+    storeGoogleToken('gcal', token as Record<string, unknown>, { tokenFile: tokenPath });
+  }
 }
 
 /** Start a temporary HTTP server to receive the OAuth callback. */
diff --git a/src/cli/gdocs-auth.ts b/src/cli/gdocs-auth.ts
index 16c0434..42c2b13 100644
--- a/src/cli/gdocs-auth.ts
+++ b/src/cli/gdocs-auth.ts
@@ -5,6 +5,7 @@ import { homedir } from 'os';
 import { createServer, type Server } from 'http';
 import { URL } from 'url';
 import { loadConfigSafe } from './shared.js';
+import { storeGoogleToken } from '../auth/google.js';
 
 const SCOPES = [
   'https://www.googleapis.com/auth/documents.readonly',
@@ -93,6 +94,10 @@ function saveToken(tokenPath: string, token: unknown): void {
   } catch {
     // chmod may fail on some filesystems — not critical
   }
+
+  if (token && typeof token === 'object' && !Array.isArray(token)) {
+    storeGoogleToken('gdocs', token as Record<string, unknown>, { tokenFile: tokenPath });
+  }
 }
 
 /** Start a temporary HTTP server to receive the OAuth callback. */
diff --git a/src/cli/gdrive-auth.ts b/src/cli/gdrive-auth.ts
index f8b13f7..c1b2fcf 100644
--- a/src/cli/gdrive-auth.ts
+++ b/src/cli/gdrive-auth.ts
@@ -5,6 +5,7 @@ import { homedir } from 'os';
 import { createServer, type Server } from 'http';
 import { URL } from 'url';
 import { loadConfigSafe } from './shared.js';
+import { storeGoogleToken } from '../auth/google.js';
 
 const SCOPES = ['https://www.googleapis.com/auth/drive.readonly'];
 const REDIRECT_PORT = 3000;
@@ -90,6 +91,10 @@ function saveToken(tokenPath: string, token: unknown): void {
   } catch {
     // chmod may fail on some filesystems — not critical
   }
+
+  if (token && typeof token === 'object' && !Array.isArray(token)) {
+    storeGoogleToken('gdrive', token as Record<string, unknown>, { tokenFile: tokenPath });
+  }
 }
 
 /** Start a temporary HTTP server to receive the OAuth callback. */
diff --git a/src/cli/gmail-auth.ts b/src/cli/gmail-auth.ts
index 24a78a0..3ca0e35 100644
--- a/src/cli/gmail-auth.ts
+++ b/src/cli/gmail-auth.ts
@@ -5,6 +5,7 @@ import { homedir } from 'os';
 import { createServer, type Server } from 'http';
 import { URL } from 'url';
 import { loadConfigSafe } from './shared.js';
+import { storeGoogleToken } from '../auth/google.js';
 
 const SCOPES = [
   // Explicitly request Gmail settings scope required by filters.create.
@@ -95,6 +96,10 @@ export function saveToken(tokenPath: string, token: unknown): void {
   } catch {
     // chmod may fail on some filesystems — not critical
   }
+
+  if (token && typeof token === 'object' && !Array.isArray(token)) {
+    storeGoogleToken('gmail', token as Record<string, unknown>, { tokenFile: tokenPath });
+  }
 }
 
 /** Start a temporary HTTP server to receive the OAuth callback. */
diff --git a/src/cli/google-auth.ts b/src/cli/google-auth.ts
new file mode 100644
index 0000000..ee61c67
--- /dev/null
+++ b/src/cli/google-auth.ts
@@ -0,0 +1,65 @@
+import type { Command } from 'commander';
+import { Command as CommanderProgram } from 'commander';
+import { registerGmailAuthCommand } from './gmail-auth.js';
+import { registerGcalAuthCommand } from './gcal-auth.js';
+import { registerGdocsAuthCommand } from './gdocs-auth.js';
+import { registerGdriveAuthCommand } from './gdrive-auth.js';
+import { registerGtasksAuthCommand } from './gtasks-auth.js';
+
+const GOOGLE_AUTH_SERVICES = ['gmail', 'gcal', 'gdocs', 'gdrive', 'gtasks'] as const;
+type GoogleAuthService = (typeof GOOGLE_AUTH_SERVICES)[number];
+
+function parseService(input: string): GoogleAuthService | null {
+  const normalized = input.trim().toLowerCase();
+  return GOOGLE_AUTH_SERVICES.find((service) => service === normalized) ?? null;
+}
+
+function registerGoogleServiceCommand(program: Command, service: GoogleAuthService): void {
+  if (service === 'gmail') {
+    registerGmailAuthCommand(program);
+    return;
+  }
+  if (service === 'gcal') {
+    registerGcalAuthCommand(program);
+    return;
+  }
+  if (service === 'gdocs') {
+    registerGdocsAuthCommand(program);
+    return;
+  }
+  if (service === 'gdrive') {
+    registerGdriveAuthCommand(program);
+    return;
+  }
+  registerGtasksAuthCommand(program);
+}
+
+export function registerGoogleAuthCommand(program: Command): void {
+  program
+    .command('google-auth')
+    .description('Authenticate Google services via OAuth2 (gmail, gcal, gdocs, gdrive, gtasks)')
+    .requiredOption('-s, --service <service>', `Service: ${GOOGLE_AUTH_SERVICES.join('|')}`)
+    .option('-c, --config <path>', 'Config file path')
+    .option('--manual', 'Manually paste the authorization code instead of using a local server')
+    .action(async (opts: { service: string; config?: string; manual?: boolean }) => {
+      const service = parseService(opts.service);
+      if (!service) {
+        console.error(
+          `Error: invalid --service "${opts.service}". Use one of: ${GOOGLE_AUTH_SERVICES.join(', ')}`,
+        );
+        process.exit(1);
+      }
+
+      const scopedProgram = new CommanderProgram();
+      registerGoogleServiceCommand(scopedProgram, service);
+
+      const args = ['node', 'flynn', `${service}-auth`];
+      if (opts.config) {
+        args.push('--config', opts.config);
+      }
+      if (opts.manual) {
+        args.push('--manual');
+      }
+      await scopedProgram.parseAsync(args, { from: 'user' });
+    });
+}
diff --git a/src/cli/gtasks-auth.ts b/src/cli/gtasks-auth.ts
index 3a534c8..dea1ce6 100644
--- a/src/cli/gtasks-auth.ts
+++ b/src/cli/gtasks-auth.ts
@@ -5,6 +5,7 @@ import { homedir } from 'os';
 import { createServer, type Server } from 'http';
 import { URL } from 'url';
 import { loadConfigSafe } from './shared.js';
+import { storeGoogleToken } from '../auth/google.js';
 
 const SCOPES = ['https://www.googleapis.com/auth/tasks.readonly'];
 const REDIRECT_PORT = 3000;
@@ -90,6 +91,10 @@ function saveToken(tokenPath: string, token: unknown): void {
   } catch {
     // chmod may fail on some filesystems — not critical
   }
+
+  if (token && typeof token === 'object' && !Array.isArray(token)) {
+    storeGoogleToken('gtasks', token as Record<string, unknown>, { tokenFile: tokenPath });
+  }
 }
 
 /** Start a temporary HTTP server to receive the OAuth callback. */
diff --git a/src/cli/index.test.ts b/src/cli/index.test.ts
index 59c93ba..f9b2f2c 100644
--- a/src/cli/index.test.ts
+++ b/src/cli/index.test.ts
@@ -23,6 +23,7 @@ describe('CLI program', () => {
     expect(commandNames).toContain('anthropic-auth');
     expect(commandNames).toContain('zai-auth');
     expect(commandNames).toContain('gemini-auth');
+    expect(commandNames).toContain('google-auth');
   });
 
   it('registers doctor strict flag on doctor command', () => {
diff --git a/src/cli/index.ts b/src/cli/index.ts
index f5f3c4c..6f02258 100644
--- a/src/cli/index.ts
+++ b/src/cli/index.ts
@@ -23,6 +23,7 @@ import { registerGcalAuthCommand } from './gcal-auth.js';
 import { registerGdocsAuthCommand } from './gdocs-auth.js';
 import { registerGdriveAuthCommand } from './gdrive-auth.js';
 import { registerGtasksAuthCommand } from './gtasks-auth.js';
+import { registerGoogleAuthCommand } from './google-auth.js';
 import { registerOpenaiAuthCommand } from './openai-auth.js';
 import { registerOpenaiKeyCommand } from './openai-key.js';
 import { registerZaiAuthCommand } from './zai-auth.js';
@@ -54,6 +55,7 @@ export function createProgram(): Command {
   registerGdocsAuthCommand(program);
   registerGdriveAuthCommand(program);
   registerGtasksAuthCommand(program);
+  registerGoogleAuthCommand(program);
   registerOpenaiAuthCommand(program);
   registerOpenaiKeyCommand(program);
   registerZaiAuthCommand(program);
diff --git a/src/google/oauth.ts b/src/google/oauth.ts
new file mode 100644
index 0000000..2854759
--- /dev/null
+++ b/src/google/oauth.ts
@@ -0,0 +1,165 @@
+import { existsSync, readFileSync, writeFileSync, mkdirSync, chmodSync } from 'fs';
+import { dirname, resolve } from 'path';
+import { homedir } from 'os';
+import { google, type Auth } from 'googleapis';
+import type { GoogleService } from '../auth/google.js';
+import { loadStoredGoogleToken, storeGoogleToken } from '../auth/google.js';
+
+interface GoogleServiceMeta {
+  tokenFile: string;
+  command: string;
+  configPath: string;
+}
+
+const GOOGLE_SERVICE_META: Record<GoogleService, GoogleServiceMeta> = {
+  gmail: {
+    tokenFile: '~/.config/flynn/gmail-token.json',
+    command: 'gmail-auth',
+    configPath: 'automation.gmail',
+  },
+  gcal: {
+    tokenFile: '~/.config/flynn/gcal-token.json',
+    command: 'gcal-auth',
+    configPath: 'automation.gcal',
+  },
+  gdocs: {
+    tokenFile: '~/.config/flynn/gdocs-token.json',
+    command: 'gdocs-auth',
+    configPath: 'automation.gdocs',
+  },
+  gdrive: {
+    tokenFile: '~/.config/flynn/gdrive-token.json',
+    command: 'gdrive-auth',
+    configPath: 'automation.gdrive',
+  },
+  gtasks: {
+    tokenFile: '~/.config/flynn/gtasks-token.json',
+    command: 'gtasks-auth',
+    configPath: 'automation.gtasks',
+  },
+};
+
+export interface GoogleOAuthCredentials {
+  client_id: string;
+  client_secret: string;
+  redirect_uris?: string[];
+}
+
+export interface CreateGoogleOAuthClientOptions {
+  service: GoogleService;
+  credentialsFile?: string;
+  tokenFile?: string;
+}
+
+export function expandPath(p: string): string {
+  if (p.startsWith('~/') || p === '~') {
+    return resolve(homedir(), p.slice(2));
+  }
+  return resolve(p);
+}
+
+export function readGoogleOAuthCredentials(
+  service: GoogleService,
+  credentialsFile?: string,
+): GoogleOAuthCredentials {
+  if (!credentialsFile) {
+    throw new Error(`No credentials_file configured. Set ${GOOGLE_SERVICE_META[service].configPath}.credentials_file in config.`);
+  }
+
+  const credentialsPath = expandPath(credentialsFile);
+  if (!existsSync(credentialsPath)) {
+    throw new Error(`Credentials file not found: ${credentialsPath}`);
+  }
+
+  const credentials = JSON.parse(readFileSync(credentialsPath, 'utf-8'));
+  const { client_id, client_secret, redirect_uris } = credentials.installed ?? credentials.web ?? {};
+  if (!client_id || !client_secret) {
+    throw new Error('Invalid credentials file — missing client_id or client_secret');
+  }
+
+  return { client_id, client_secret, redirect_uris };
+}
+
+export function tokenPathForGoogleService(service: GoogleService, configuredTokenPath?: string): string {
+  return expandPath(configuredTokenPath ?? GOOGLE_SERVICE_META[service].tokenFile);
+}
+
+function readTokenFromFile(tokenPath: string): Record<string, unknown> | null {
+  if (!existsSync(tokenPath)) {
+    return null;
+  }
+  try {
+    return JSON.parse(readFileSync(tokenPath, 'utf-8')) as Record<string, unknown>;
+  } catch {
+    return null;
+  }
+}
+
+function writeTokenToFile(tokenPath: string, token: Record<string, unknown>): void {
+  const dir = dirname(tokenPath);
+  if (!existsSync(dir)) {
+    mkdirSync(dir, { recursive: true });
+  }
+  writeFileSync(tokenPath, JSON.stringify(token, null, 2), 'utf-8');
+  try {
+    chmodSync(tokenPath, 0o600);
+  } catch {
+    // chmod may fail on some filesystems
+  }
+}
+
+function loadTokenWithMigration(service: GoogleService, tokenPath: string, credentialsPath: string): Record<string, unknown> | null {
+  const fromStore = loadStoredGoogleToken(service);
+  if (fromStore) {
+    return fromStore;
+  }
+
+  const fromFile = readTokenFromFile(tokenPath);
+  if (!fromFile) {
+    return null;
+  }
+
+  storeGoogleToken(service, fromFile, {
+    tokenFile: tokenPath,
+    credentialsFile: credentialsPath,
+  });
+  return fromFile;
+}
+
+export function authCommandForGoogleService(service: GoogleService): string {
+  return GOOGLE_SERVICE_META[service].command;
+}
+
+export function createGoogleOAuth2Client(options: CreateGoogleOAuthClientOptions): Auth.OAuth2Client {
+  const { service, credentialsFile, tokenFile } = options;
+  const creds = readGoogleOAuthCredentials(service, credentialsFile);
+  const credentialsPath = expandPath(credentialsFile ?? '');
+  const resolvedTokenPath = tokenPathForGoogleService(service, tokenFile);
+
+  const oauth2Client = new google.auth.OAuth2(
+    creds.client_id,
+    creds.client_secret,
+    creds.redirect_uris?.[0] ?? 'http://localhost',
+  );
+
+  let currentToken = loadTokenWithMigration(service, resolvedTokenPath, credentialsPath);
+  if (!currentToken) {
+    throw new Error(
+      `Token file not found: ${resolvedTokenPath}. Run "flynn ${authCommandForGoogleService(service)}" to authenticate.`,
+    );
+  }
+
+  oauth2Client.setCredentials(currentToken);
+  if (typeof oauth2Client.on === 'function') {
+    oauth2Client.on('tokens', (newTokens) => {
+      currentToken = { ...currentToken, ...newTokens };
+      storeGoogleToken(service, currentToken, {
+        tokenFile: resolvedTokenPath,
+        credentialsFile: credentialsPath,
+      });
+      writeTokenToFile(resolvedTokenPath, currentToken);
+    });
+  }
+
+  return oauth2Client;
+}
diff --git a/src/tools/builtin/gcal.ts b/src/tools/builtin/gcal.ts
index 136446c..9ff9a6a 100644
--- a/src/tools/builtin/gcal.ts
+++ b/src/tools/builtin/gcal.ts
@@ -1,52 +1,14 @@
-import { google, type Auth } from 'googleapis';
-import { readFileSync, existsSync } from 'fs';
-import { resolve } from 'path';
-import { homedir } from 'os';
+import { google } from 'googleapis';
 import type { GcalConfig } from '../../config/schema.js';
+import { createGoogleOAuth2Client } from '../../google/oauth.js';
 import type { Tool, ToolResult } from '../types.js';
 
-/** Expand ~ to home directory. */
-function expandPath(p: string): string {
-  if (p.startsWith('~/') || p === '~') {
-    return resolve(homedir(), p.slice(2));
-  }
-  return resolve(p);
-}
-
-/** Create an OAuth2 client from Google Calendar config (credentials + token files). */
-function createOAuth2Client(config: NonNullable<GcalConfig>): Auth.OAuth2Client {
-  const credentialsPath = config.credentials_file;
-  if (!credentialsPath) {
-    throw new Error('No credentials_file configured. Set automation.gcal.credentials_file in config.');
-  }
-
-  const expandedCredsPath = expandPath(credentialsPath);
-  if (!existsSync(expandedCredsPath)) {
-    throw new Error(`Credentials file not found: ${expandedCredsPath}`);
-  }
-
-  const credentials = JSON.parse(readFileSync(expandedCredsPath, 'utf-8'));
-  const { client_id, client_secret, redirect_uris } = credentials.installed ?? credentials.web ?? {};
-
-  if (!client_id || !client_secret) {
-    throw new Error('Invalid credentials file — missing client_id or client_secret');
-  }
-
-  const oauth2Client = new google.auth.OAuth2(
-    client_id,
-    client_secret,
-    redirect_uris?.[0] ?? 'http://localhost',
-  );
-
-  const tokenPath = expandPath(config.token_file ?? '~/.config/flynn/gcal-token.json');
-  if (!existsSync(tokenPath)) {
-    throw new Error(`Token file not found: ${tokenPath}. Run "flynn gcal-auth" to authenticate.`);
-  }
-
-  const token = JSON.parse(readFileSync(tokenPath, 'utf-8'));
-  oauth2Client.setCredentials(token);
-
-  return oauth2Client;
+function createOAuth2Client(config: NonNullable<GcalConfig>) {
+  return createGoogleOAuth2Client({
+    service: 'gcal',
+    credentialsFile: config.credentials_file,
+    tokenFile: config.token_file,
+  });
 }
 
 interface EventSummary {
diff --git a/src/tools/builtin/gdocs.ts b/src/tools/builtin/gdocs.ts
index bfd9234..3a93b6a 100644
--- a/src/tools/builtin/gdocs.ts
+++ b/src/tools/builtin/gdocs.ts
@@ -1,52 +1,14 @@
-import { google, type Auth } from 'googleapis';
-import { readFileSync, existsSync } from 'fs';
-import { resolve } from 'path';
-import { homedir } from 'os';
+import { google } from 'googleapis';
 import type { GdocsConfig } from '../../config/schema.js';
+import { createGoogleOAuth2Client } from '../../google/oauth.js';
 import type { Tool, ToolResult } from '../types.js';
 
-/** Expand ~ to home directory. */
-function expandPath(p: string): string {
-  if (p.startsWith('~/') || p === '~') {
-    return resolve(homedir(), p.slice(2));
-  }
-  return resolve(p);
-}
-
-/** Create an OAuth2 client from Google Docs config (credentials + token files). */
-function createOAuth2Client(config: NonNullable<GdocsConfig>): Auth.OAuth2Client {
-  const credentialsPath = config.credentials_file;
-  if (!credentialsPath) {
-    throw new Error('No credentials_file configured. Set automation.gdocs.credentials_file in config.');
-  }
-
-  const expandedCredsPath = expandPath(credentialsPath);
-  if (!existsSync(expandedCredsPath)) {
-    throw new Error(`Credentials file not found: ${expandedCredsPath}`);
-  }
-
-  const credentials = JSON.parse(readFileSync(expandedCredsPath, 'utf-8'));
-  const { client_id, client_secret, redirect_uris } = credentials.installed ?? credentials.web ?? {};
-
-  if (!client_id || !client_secret) {
-    throw new Error('Invalid credentials file — missing client_id or client_secret');
-  }
-
-  const oauth2Client = new google.auth.OAuth2(
-    client_id,
-    client_secret,
-    redirect_uris?.[0] ?? 'http://localhost',
-  );
-
-  const tokenPath = expandPath(config.token_file ?? '~/.config/flynn/gdocs-token.json');
-  if (!existsSync(tokenPath)) {
-    throw new Error(`Token file not found: ${tokenPath}. Run "flynn gdocs-auth" to authenticate.`);
-  }
-
-  const token = JSON.parse(readFileSync(tokenPath, 'utf-8'));
-  oauth2Client.setCredentials(token);
-
-  return oauth2Client;
+function createOAuth2Client(config: NonNullable<GdocsConfig>) {
+  return createGoogleOAuth2Client({
+    service: 'gdocs',
+    credentialsFile: config.credentials_file,
+    tokenFile: config.token_file,
+  });
 }
 
 interface DocSummary {
diff --git a/src/tools/builtin/gdrive.ts b/src/tools/builtin/gdrive.ts
index 8b35251..fe98c69 100644
--- a/src/tools/builtin/gdrive.ts
+++ b/src/tools/builtin/gdrive.ts
@@ -1,52 +1,14 @@
-import { google, type Auth } from 'googleapis';
-import { readFileSync, existsSync } from 'fs';
-import { resolve } from 'path';
-import { homedir } from 'os';
+import { google } from 'googleapis';
 import type { GdriveConfig } from '../../config/schema.js';
+import { createGoogleOAuth2Client } from '../../google/oauth.js';
 import type { Tool, ToolResult } from '../types.js';
 
-/** Expand ~ to home directory. */
-function expandPath(p: string): string {
-  if (p.startsWith('~/') || p === '~') {
-    return resolve(homedir(), p.slice(2));
-  }
-  return resolve(p);
-}
-
-/** Create an OAuth2 client from config (credentials + token files). */
-function createOAuth2Client(config: NonNullable<GdriveConfig>): Auth.OAuth2Client {
-  const credentialsPath = config.credentials_file;
-  if (!credentialsPath) {
-    throw new Error('No credentials_file configured. Set automation.gdrive.credentials_file in config.');
-  }
-
-  const expandedCredsPath = expandPath(credentialsPath);
-  if (!existsSync(expandedCredsPath)) {
-    throw new Error(`Credentials file not found: ${expandedCredsPath}`);
-  }
-
-  const credentials = JSON.parse(readFileSync(expandedCredsPath, 'utf-8'));
-  const { client_id, client_secret, redirect_uris } = credentials.installed ?? credentials.web ?? {};
-
-  if (!client_id || !client_secret) {
-    throw new Error('Invalid credentials file — missing client_id or client_secret');
-  }
-
-  const oauth2Client = new google.auth.OAuth2(
-    client_id,
-    client_secret,
-    redirect_uris?.[0] ?? 'http://localhost',
-  );
-
-  const tokenPath = expandPath(config.token_file ?? '~/.config/flynn/gdrive-token.json');
-  if (!existsSync(tokenPath)) {
-    throw new Error(`Token file not found: ${tokenPath}. Run "flynn gdrive-auth" to authenticate.`);
-  }
-
-  const token = JSON.parse(readFileSync(tokenPath, 'utf-8'));
-  oauth2Client.setCredentials(token);
-
-  return oauth2Client;
+function createOAuth2Client(config: NonNullable<GdriveConfig>) {
+  return createGoogleOAuth2Client({
+    service: 'gdrive',
+    credentialsFile: config.credentials_file,
+    tokenFile: config.token_file,
+  });
 }
 
 interface FileSummary {
diff --git a/src/tools/builtin/gmail.ts b/src/tools/builtin/gmail.ts
index 2ef67be..f91ecea 100644
--- a/src/tools/builtin/gmail.ts
+++ b/src/tools/builtin/gmail.ts
@@ -1,53 +1,15 @@
-import { google, type Auth } from 'googleapis';
-import { readFileSync, existsSync } from 'fs';
-import { resolve } from 'path';
-import { homedir } from 'os';
+import { google } from 'googleapis';
 import type { GmailConfig } from '../../config/schema.js';
+import { createGoogleOAuth2Client } from '../../google/oauth.js';
 import type { Tool, ToolResult } from '../types.js';
 import { sanitizeHtml } from '../../utils/html.js';
 
-/** Expand ~ to home directory. */
-function expandPath(p: string): string {
-  if (p.startsWith('~/') || p === '~') {
-    return resolve(homedir(), p.slice(2));
-  }
-  return resolve(p);
-}
-
-/** Create an OAuth2 client from Gmail config (credentials + token files). */
-function createOAuth2Client(config: NonNullable<GmailConfig>): Auth.OAuth2Client {
-  const credentialsPath = config.credentials_file;
-  if (!credentialsPath) {
-    throw new Error('No credentials_file configured. Set automation.gmail.credentials_file in config.');
-  }
-
-  const expandedCredsPath = expandPath(credentialsPath);
-  if (!existsSync(expandedCredsPath)) {
-    throw new Error(`Credentials file not found: ${expandedCredsPath}`);
-  }
-
-  const credentials = JSON.parse(readFileSync(expandedCredsPath, 'utf-8'));
-  const { client_id, client_secret, redirect_uris } = credentials.installed ?? credentials.web ?? {};
-
-  if (!client_id || !client_secret) {
-    throw new Error('Invalid credentials file — missing client_id or client_secret');
-  }
-
-  const oauth2Client = new google.auth.OAuth2(
-    client_id,
-    client_secret,
-    redirect_uris?.[0] ?? 'http://localhost',
-  );
-
-  const tokenPath = expandPath(config.token_file ?? '~/.config/flynn/gmail-token.json');
-  if (!existsSync(tokenPath)) {
-    throw new Error(`Token file not found: ${tokenPath}. Run "flynn gmail-auth" to authenticate.`);
-  }
-
-  const token = JSON.parse(readFileSync(tokenPath, 'utf-8'));
-  oauth2Client.setCredentials(token);
-
-  return oauth2Client;
+function createOAuth2Client(config: NonNullable<GmailConfig>) {
+  return createGoogleOAuth2Client({
+    service: 'gmail',
+    credentialsFile: config.credentials_file,
+    tokenFile: config.token_file,
+  });
 }
 
 interface EmailSummary {
diff --git a/src/tools/builtin/gtasks.ts b/src/tools/builtin/gtasks.ts
index 1543a55..e687e8e 100644
--- a/src/tools/builtin/gtasks.ts
+++ b/src/tools/builtin/gtasks.ts
@@ -1,52 +1,14 @@
-import { google, type Auth } from 'googleapis';
-import { readFileSync, existsSync } from 'fs';
-import { resolve } from 'path';
-import { homedir } from 'os';
+import { google } from 'googleapis';
 import type { GtasksConfig } from '../../config/schema.js';
+import { createGoogleOAuth2Client } from '../../google/oauth.js';
 import type { Tool, ToolResult } from '../types.js';
 
-/** Expand ~ to home directory. */
-function expandPath(p: string): string {
-  if (p.startsWith('~/') || p === '~') {
-    return resolve(homedir(), p.slice(2));
-  }
-  return resolve(p);
-}
-
-/** Create an OAuth2 client from Google Tasks config (credentials + token files). */
-function createOAuth2Client(config: NonNullable<GtasksConfig>): Auth.OAuth2Client {
-  const credentialsPath = config.credentials_file;
-  if (!credentialsPath) {
-    throw new Error('No credentials_file configured. Set automation.gtasks.credentials_file in config.');
-  }
-
-  const expandedCredsPath = expandPath(credentialsPath);
-  if (!existsSync(expandedCredsPath)) {
-    throw new Error(`Credentials file not found: ${expandedCredsPath}`);
-  }
-
-  const credentials = JSON.parse(readFileSync(expandedCredsPath, 'utf-8'));
-  const { client_id, client_secret, redirect_uris } = credentials.installed ?? credentials.web ?? {};
-
-  if (!client_id || !client_secret) {
-    throw new Error('Invalid credentials file — missing client_id or client_secret');
-  }
-
-  const oauth2Client = new google.auth.OAuth2(
-    client_id,
-    client_secret,
-    redirect_uris?.[0] ?? 'http://localhost',
-  );
-
-  const tokenPath = expandPath(config.token_file ?? '~/.config/flynn/gtasks-token.json');
-  if (!existsSync(tokenPath)) {
-    throw new Error(`Token file not found: ${tokenPath}. Run "flynn gtasks-auth" to authenticate.`);
-  }
-
-  const token = JSON.parse(readFileSync(tokenPath, 'utf-8'));
-  oauth2Client.setCredentials(token);
-
-  return oauth2Client;
+function createOAuth2Client(config: NonNullable<GtasksConfig>) {
+  return createGoogleOAuth2Client({
+    service: 'gtasks',
+    credentialsFile: config.credentials_file,
+    tokenFile: config.token_file,
+  });
 }
 
 interface TaskListSummary {