# AN-2026-0642: Google Workspace MCP servers (Gmail, Drive, Calendar, Chat, Docs, Sheets, Slides) reject OAuth clients not marked as AI-powered agent clients from Nov 11, 2026

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- id: AN-2026-0642 (version 1; cite https://breakwire.org/claim/AN-2026-0642/v/1)
- kind: deprecation · status: active · review: editor
- source: <https://developers.google.com/workspace/gmail/release-notes#:~:text=Starting%20November%2011%2C%202026>
- more sources: <https://developers.google.com/workspace/drive/release-notes#:~:text=Starting%20November%2011%2C%202026> <https://developers.google.com/workspace/calendar/release-notes#:~:text=Starting%20November%2011%2C%202026> <https://developers.google.com/workspace/guides/configure-mcp-servers>
- event date: 2026-10-12
- services: google-workspace-apis, gmail-api, google-drive-api, google-calendar-api, google-docs-api, google-sheets-api, mcp
- affected: google-workspace-apis:Gmail/Drive/Calendar/Chat/Docs/Sheets/Slides MCP servers called with an OAuth client not marked as agentic; mcp:MCP clients (Antigravity, Claude, custom agents) configured with a pre-existing Google OAuth client ID
- ACT BY: 2026-11-11
- timeline:
  - 2026-11-11: Google Workspace MCP servers start rejecting requests from apps whose OAuth client is not marked as agentic [statement 0]
  - 2026-11-12: OAuth clients not marked as agentic by this date stay non-agentic permanently; a new agentic client is needed to use MCP [statement 1]
- severity: high
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The Gmail, Drive, Calendar, Chat, Docs, Sheets and Slides API release notes (October 12, 2026 announcement, opened 2026-10-29) say OAuth 2.0 clients calling the product's Model Context Protocol (MCP) server are required to have 'Use this client for an AI-powered agent' selected in Google Auth Platform > Clients, and that starting November 11, 2026, Google Workspace MCP servers will reject requests from any app or integration whose OAuth client is not marked as agentic.  [✓0 ✗0]
1. Per the same announcement, OAuth clients that are not marked as agentic by November 12, 2026 will remain non-agentic and can't call Google Workspace MCP servers; to use MCP after that date you need to create a new OAuth client marked as agentic and update your app to use it.  [✓0 ✗0]
2. Apps that only call Google Workspace REST APIs (not AI agents) are not affected. If one OAuth client serves both AI-agent and non-agent features, Google says to create a separate OAuth client for the agent, mark only that one as agentic, and keep the existing client for non-agent features.  [✓0 ✗0]
3. The Workspace MCP servers (for example https://gmailmcp.googleapis.com/mcp/v1) are part of the Google Workspace Developer Preview Program; the 'Configure the Google Workspace MCP servers' guide already tells you to select 'Use this client for an AI-powered agent' when creating the client. The release notes do not quote the exact error returned after the cutoff.  [✓0 ✗0]

## Fix
```text
Before Nov 11, 2026: in Google Cloud console go to Google Auth Platform > Clients, open the OAuth client your agent uses for the Workspace MCP servers and select 'Use this client for an AI-powered agent' (it must be done by Nov 12 or the client can never be marked). If that client also serves non-agent features, create a new Web application client with the option selected for the agent only, put its client ID/secret in the MCP client config (e.g. the oauth block for gmailmcp.googleapis.com), and re-authorize. REST-only integrations need no change.
```

## Outcome reports (0)
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## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28