claude-code - 💡(How to fix) Fix [BUG] Cowork macOS: Gmail and Google Calendar MCP connectors return "The caller does not have permission" on every call for one account; other users on the same Workspace tenant unaffected

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Note: This is a Cowork bug, filed in this repo because related Cowork connector bugs have landed here (#48130 Cowork Windows Gmail connector, #55474 Gmail/Calendar hosted endpoints, #56794 Gmail/Calendar/Drive not syncing). This is not a Claude Code CLI bug.

Cowork's Gmail and Google Calendar MCP connectors return "The caller does not have permission" on every call for my account specifically, since April 20, 2026.

Other users on the same Google Workspace tenant (overcast.com) run the same connectors without issue. The Drive connector on my account works normally. Only Gmail and Calendar fail, and only for my account.

This strongly suggests account-state corruption on Anthropic's side that requires server-side intervention to resolve.

Support ticket 215474011486857 has been open for thirty-six days with zero substantive human responses across all standard channels. The only reply was an automated template from "Wallace from Anthropic" on April 28 closing with "further replies to this ticket may not be monitored."

Environment:

• Product: Cowork on macOS
• Plan: Max
• Account: paid Google Workspace tenant (overcast.com); admin-side OAuth grants confirmed intact
• Other users on same Workspace tenant: Gmail and Calendar work normally
• Drive connector on my account: works normally
• Gmail and Calendar connectors on my account: fail with "The caller does not have permission" on every tool call

Client-side troubleshooting completed:

1. Uninstalled and reinstalled the Gmail connector. Re-granted all OAuth scopes including "Read, compose, send, and permanently delete all your email." No change.
2. Same for the Calendar connector. No change.
3. Verified at myaccount.google.com/permissions that Claude/Cowork was granted with appropriate scopes.
4. Workspace admin verified the Anthropic OAuth app is not blocked or scope-restricted for the domain.
5. Confirmed the Drive connector on the same account works, ruling out generic OAuth issues for this account.
6. Confirmed other users on overcast.com run Gmail/Calendar connectors normally.

The client-side surface is exhausted. The remaining hypothesis is account-state corruption on Anthropic's side.

Related issues that may share root cause:

• #228 in anthropics/claude-ai-mcp — OAuth token refresh never attempted for custom connectors via mcp-proxy.anthropic.com
• #55474 — Gmail/Calendar hosted MCP endpoints (*.mcp.claude.com) return 404
• #56794 — claude.ai Gmail/Calendar/Drive connectors not syncing
• #48130 — Cowork Windows: Gmail connector MCP server not responding after successful OAuth

What Should Happen?

A named engineer with access to the OAuth token state on my account should be able to diff against a working user on the same Workspace domain (overcast.com) and identify the corrupted record. Estimated effort to fix: minutes, not hours.

Expected behavior: Gmail and Calendar MCP tools succeed with valid OAuth tokens, returning normal data. Currently they return "The caller does not have permission" on every call, while all other connectors on the same account (notably Drive) work fine.

I am happy to provide my Anthropic account email and any server-side identifiers via DM or any secure channel that does not route through [email protected].

This is one account on one product that has been silently broken for thirty-six days. The fix is asymmetric: low effort for Anthropic engineering with server-side access, ongoing high cost for me as a Max plan customer relying on the affected features daily.

Error Messages/Logs

"The caller does not have permission"

This is the exact error string returned on every Gmail and Calendar MCP tool call since April 20, 2026. No additional stack trace or detail is surfaced to the Cowork UI; the error is identical across every call regardless of which tool is invoked (gmail.search, gmail.send, calendar.list_events, calendar.create_event, etc.).

Steps to Reproduce

1. Open Cowork on macOS as the affected account.
2. Verify that Gmail and Calendar connectors are configured at Settings > Connectors (they show as connected; OAuth completed successfully, scopes granted).
3. In any session, invoke any tool from the Gmail or Calendar connectors. Examples that fail:
   • "Search my Gmail for emails from X"
   • "List my Calendar events for today"
   • "Send an email to X"
   • "Create a calendar event"
4. Every tool call returns: "The caller does not have permission"
5. In the same session on the same account, invoke any tool from the Drive connector (e.g., "Search my Drive for a file"). Drive returns normal results successfully.

Reproducibility: 100%. Every Gmail and Calendar tool call has failed identically since April 20, 2026. Drive on the same account has worked uninterrupted across the same period.

Cross-account confirmation: Other users on the same Google Workspace tenant (overcast.com) executing the same tool calls receive normal results. The failure is isolated to my account specifically, while every other connector on my account functions normally.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Prior to April 20, 2026 (Cowork app)

Claude Code Version

N/A — this is a Cowork bug, not Claude Code CLI. See description for product context.

Platform

Other

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This bug is in the Cowork product (Anthropic's desktop app), not Claude Code CLI. Filing in this repo because similar Cowork connector bugs have landed here (e.g., #48130). Happy to move if a different repo is more appropriate.