[BUG] Cowork mode: MCP connectors (Asana, Google Calendar) return 403 errors despite working in Claude Chat
Preflight Checklist
- [x] I have searched existing issues and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code
What's Wrong?
MCP connectors (specifically Asana and Google Calendar) that work correctly in Claude Chat fail with HTTP 403 errors when used in Cowork mode.
When attempting to use any Asana or Google Calendar MCP tool in Cowork mode, every call returns:Tool call failed: 403
The same connectors work perfectly in standard Claude Chat, suggesting the OAuth credentials are not being properly passed through in the Cowork containerized environment.
This affects both:
- Native Asana MCP tools (mcp__70413d83-a9a5-47f8-8370-f4af625dd2a9__*)
- Zapier-based Asana/Calendar tools (mcp__816e0fba-d385-4171-9ff1-0f48d617f38b__*)
What Should Happen?
MCP connectors should work identically in Cowork mode as they do in Claude Chat. The OAuth credentials should be properly passed through to the containerized Cowork environment, allowing authenticated API calls to succeed.
Error Messages/Logs
Tool call failed: 403
Example calls that fail:
- mcp__70413d83-a9a5-47f8-8370-f4af625dd2a9__asana_list_workspaces
- mcp__70413d83-a9a5-47f8-8370-f4af625dd2a9__asana_get_user
- mcp__70413d83-a9a5-47f8-8370-f4af625dd2a9__asana_search_tasks
- mcp__816e0fba-d385-4171-9ff1-0f48d617f38b__google_calendar_find_multiple_events
- mcp__816e0fba-d385-4171-9ff1-0f48d617f38b__asana_find_all_tasks_from_project
All return the same generic 403 error with no additional details.Steps to Reproduce
- Open Claude Chat (claude.ai) and verify Asana/Google Calendar connectors are enabled and working
- Use an Asana tool (e.g., "Show my Asana tasks") - confirm it works
- Start a new Cowork mode session from Claude Desktop
- Ask Claude to use the same Asana connector (e.g., "Show my overdue Asana tasks")
- Observe: Tool returns
Tool call failed: 403
Key observation: The same MCP connectors that work in Claude Chat fail in Cowork mode, despite being the same authenticated user session.
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
Cowork mode (Research Preview) - January 2026
Platform
Anthropic API
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
Related issues:
- #11146 - Claude Desktop: Web session mode lacks MCP server access despite configuration (similar but distinct - that's about complete lack of access, this is about 403 auth failures)
Environment:
- Claude Desktop with Cowork mode enabled
- MCP connectors authenticated and working in Claude Chat
- macOS
Workaround attempted:
- None available - the connectors simply don't work in Cowork mode
This appears to be an OAuth credential passthrough issue specific to the Cowork containerized environment.
5 Comments
I have a similar issue with my custom connector/mcp.Reached out on X, but no response yet unfortunately.
Same issue with Jotform connector.
I do want to add that I added a bug report from Within Claude Desktop, there is a 'bug' symbol in the lower left if you're in cowork mode. I would suggest that route as well to get in on the radar.
@sbayd @avinden For me the connection is currently active (solved)
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.