Google Static OAuth Authentication not working in MCP

Where does the bug appear (feature/product)?

Background Agent (GitHub, Slack, Web, Linear)

Describe the Bug

Adding the static OAuth mcp entry doesn’t prompt for google authentication

Steps to Reproduce

  1. Add the entry in mcp.json in cursor agents
    "Google Calendar": {
      "url": "https://calendarmcp.googleapis.com/mcp/v1",
      "headers": {},
      "auth": {
        "CLIENT_ID": "....apps.googleusercontent.com",
        "CLIENT_SECRET": "..."
      }
  1. It shows a green dot
  2. Start an agent on https://cursor.com/agents
  3. Agent logs say mcp is Unauthorized and there’s no login prompt either while adding the mcp or while running the agent.

Google OAuth credentials were created following this guide: Configure the Calendar MCP server  |  Google Calendar  |  Google for Developers (I have tested with both Desktop and Web application types, none of them work)
The official guide to mcp connection at Configure MCP in an AI application  |  Google Cloud MCP servers  |  Google Cloud Documentation states to add cursor://anysphere.cursor-mcp/oauth/callback as the redirect URI but google client screen shows an error while adding the redirect uri stating that it needs to be a valid TLD.

Expected Behavior

Cursor should prompt to authenticate when turning on the MCP (similar to other MCPs like Slack, Atlassian etc.)

Operating System

Linux

Version Information

Web version of cursor agents at https://cursor.com/agents

For AI issues: which model did you use?

Composer 2.5

Does this stop you from using Cursor

Yes - Cursor is unusable

Answered here as not currently supported as a 1st class integration: Hosted Gmail MCP (user-gmail): Tools UI shows connected after logout/toggle, but Agent MCP tool calls return Unauthorized; OAuth reconnect never prompts - #12 by deanrie