google-cloud-oauth

name: google-cloud-oauth description: Set up Google Cloud OAuth credentials for Google APIs (Calendar, Drive, Gmail, etc.). Use when configuring Google API access, creating OAuth credentials, or troubleshooting Google authentication errors.

Google Cloud OAuth Setup

Guide for creating OAuth 2.0 credentials to access Google APIs.

Quick Setup Steps

1. Create Google Cloud project
2. Enable the required API
3. Configure OAuth consent screen
4. Create OAuth credentials
5. Download credentials.json

Step 1: Create Project

1. Go to console.cloud.google.com
2. Click project dropdown → New Project
3. Name it (e.g., "My App")
4. Click Create

Work account can't create project? Use personal Gmail for the project, authorize with work account later.

Step 2: Enable API

1. Select your project
2. Go to APIs & Services → Library
3. Search for the API (e.g., "Google Calendar API")
4. Click Enable

Step 3: OAuth Consent Screen

1. Go to APIs & Services → OAuth consent screen
2. Select External (or Internal for Workspace)
3. Fill required fields:
   • App name
   • User support email
   • Developer contact email
4. Click Save and Continue through remaining steps
5. On Test users, add emails that will authorize the app

Step 4: Create Credentials

1. Go to APIs & Services → Credentials
2. Click + Create Credentials → OAuth client ID
3. Application type: Desktop app
4. Name it (e.g., "Desktop Client")
5. Click Create
6. Click Download JSON
7. Save as credentials.json in your project

Step 5: First Authorization

Run your app - it will open a browser for authorization. After consent, a token.json is cached for future use.

Node.js Implementation

import { authenticate } from '@google-cloud/local-auth';
import { google } from 'googleapis';
import * as path from 'path';
import * as fs from 'fs';

const SCOPES = ['https://www.googleapis.com/auth/calendar.readonly'];
const TOKEN_PATH = path.join(process.cwd(), 'token.json');
const CREDENTIALS_PATH = path.join(process.cwd(), 'credentials.json');

async function authorize() {
  // Check for existing token
  if (fs.existsSync(TOKEN_PATH)) {
    const token = JSON.parse(fs.readFileSync(TOKEN_PATH, 'utf-8'));
    const auth = new google.auth.OAuth2();
    auth.setCredentials(token);
    return auth;
  }

  // Authenticate and save token
  const auth = await authenticate({
    scopes: SCOPES,
    keyfilePath: CREDENTIALS_PATH,
  });
  
  if (auth.credentials) {
    fs.writeFileSync(TOKEN_PATH, JSON.stringify(auth.credentials));
  }
  
  return auth;
}

Required dependencies:

npm install googleapis @google-cloud/local-auth

Common Errors

"access_denied" (Error 403)

The authorizing email isn't a test user.

Fix: Go to OAuth consent screen → Test users → Add the email.

"Organization required" when creating project

Work/school account has restrictions.

Fix: Use personal Gmail for the Cloud project. You can still authorize with your work account later.

"Credentials not found"

The credentials.json file is missing or in wrong location.

Fix: Download from Cloud Console → Credentials → your OAuth client → Download JSON.

Scopes Reference

Files

Add both to .gitignore.

Personal Extensions

If ./PERSONAL.md exists in this skill's directory, incorporate its contents as additional instructions specific to your OAuth setup.

Do not modify this SKILL.md file directly. Create a PERSONAL.md file for your customizations instead.