Google Workspace plugins OAuth fails: Error 400 invalid_request on cursor:// redirect

[Fumiaki_Yamazaki]

Where does the bug appear (feature/product)?

Somewhere else…

Describe the Bug

Google Workspace plugins install, but authentication never completes.

In Customize > MCPs, google-calendar, google-docs, google-drive, and google-sheets stay on “Needs Authentication in Cloud”.

Clicking Authenticate opens Google Sign-in for [email protected], then Google blocks with:

Access blocked: Authorization Error
Error 400: invalid_request

Error details show:
redirect_uri=cursor://anysphere.cursor-mcp/oauth/callback
flowName=GeneralOAuthFlow

This looks like Cursor/Anysphere OAuth redirect URI is rejected by Google. Cannot finish connect. Retrying Authenticate hits the same error.

Mac, Cursor 3.14.7. Screenshots attached.

Steps to Reproduce

1. Open Cursor Desktop on Mac (3.14.7).
2. Go to Customize > MCPs.
3. Install Google Workspace plugins (google-sheets, google-drive, google-docs, google-calendar).
4. See them under Needs Attention: “Needs Authentication in Cloud”.
5. Click Authenticate on google-sheets (or any of them).
6. Google Sign-in opens for [email protected].
7. After choosing the account, Google shows:
   Access blocked: Authorization Error
   Error 400: invalid_request
8. Error details show:
   redirect_uri=cursor://anysphere.cursor-mcp/oauth/callback
   flowName=GeneralOAuthFlow
9. Click Done. Plugins remain “Needs Authentication in Cloud”. Retrying Authenticate repeats the same error.

Screenshots / Screen Recordings

Operating System

MacOS

Version Information

Version: 3.14.7
VSCode Version: 1.128.0
Commit: a758f2241ca99fecf380180b6cbdbbce0f1f42c0

For AI issues: which model did you use?

grok 4.5

Does this stop you from using Cursor

No - Cursor works, but with this issue