Gmail Credential Stubs

Set up Gmail credential stubs so MCP servers that need Google OAuth tokens can start without manual auth flows or token files.

Applies to

MCP Server	Credential directory
@gongrzhe/server-gmail-autoauth-mcp	~/.gmail-mcp/

Other Google services (Calendar, Drive, Sheets) have their own credential stub pages.

Create the stubs

Create the directory if it doesn’t exist: mkdir -p ~/.gmail-mcp

~/.gmail-mcp/gcp-oauth.keys.json

{
  "installed": {
    "client_id": "onecli-managed.apps.googleusercontent.com",
    "client_secret": "onecli-managed",
    "redirect_uris": ["http://localhost:3000/oauth2callback"]
  }
}

~/.gmail-mcp/credentials.json

{
  "access_token": "onecli-managed",
  "refresh_token": "onecli-managed",
  "token_type": "Bearer",
  "expiry_date": 0
}

Rules

• Never overwrite existing files that don’t contain onecli-managed values. The user may have real credentials.
• All sentinel values use the string onecli-managed so they’re easy to detect programmatically.

How it works

expiry_date: 0 tells google-auth-library the token is expired. It immediately sends a refresh request to oauth2.googleapis.com/token with refresh_token: "onecli-managed". The OneCLI gateway intercepts that request and returns a real access token using the app connection you registered.