[BUG] Cowork Tableau MCP Connector returns 401 Unauthorized on all endpoints despite valid PAT credentials

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?

The Cowork Tableau MCP connector returns 401 Unauthorized on every API endpoint, despite providing valid Personal Access Token (PAT) credentials.

Steps to Reproduce:

1. Connect Tableau MCP connector in Cowork with valid PAT credentials (token name + secret)
2. 2. Tableau Cloud site: prod-apnortheast-a.online.tableau.com, site name: karrot
3. 3. Attempt any MCP tool call (e.g., list-workbooks, list-views, search-content, get-view-data)
4. 4. All calls return 401 Unauthorized

Evidence:

• The same PAT credentials work correctly via direct Tableau REST API calls (tested with curl)
• - The same PAT credentials work when accessing Tableau Cloud via browser (confirmed working)
• - - Disconnecting and reconnecting the Tableau MCP connector multiple times did not resolve the issue
• - - - All other MCP connectors (BigQuery, Notion, Slack, Linear) work correctly in the same Cowork session

Error Response (consistent across all endpoints):

Status: 401 Unauthorized

What Should Happen?

The Tableau MCP connector should authenticate successfully with valid PAT credentials and return data from all Tableau Cloud endpoints (list-workbooks, list-views, get-view-data, etc.) without 401 errors.

Error Messages/Logs

Tableau MCP tool call: list-workbooks
Response: 401 Unauthorized

Tableau MCP tool call: list-views
Response: 401 Unauthorized

Tableau MCP tool call: search-content (query: "로컬비즈니스")
Response: 401 Unauthorized

Tableau MCP tool call: get-view-data
Response: 401 Unauthorized

All endpoints consistently return 401 regardless of the specific tool or parameters used.

Steps to Reproduce

1. Open Cowork desktop app
2. 2. Go to Settings > Connectors > Add Tableau connector
3. 3. Enter Tableau Cloud credentials:
4. - Server URL: https://prod-apnortheast-a.online.tableau.com
5. - Site name: karrot
6. - PAT name: (valid token name)
7. - PAT secret: (valid token secret)
8. 4. Connection shows as "Connected" successfully
9. 5. In a Cowork session, try any Tableau MCP tool (e.g., ask "list my Tableau workbooks")
10. 6. Observe: All calls return 401 Unauthorized
11. 7. Disconnect and reconnect the Tableau connector - same result
12. 8. Verify PAT works via direct REST API: curl -X POST https://prod-apnortheast-a.online.tableau.com/api/3.22/auth/signin with the same credentials - returns 200 OK with valid auth token

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Cowork Desktop App (latest version as of 2026-03-26)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Environment:

• Cowork Desktop App on macOS
• - Tableau Cloud: prod-apnortheast-a.online.tableau.com (Asia-Pacific region)
• - - Site: karrot
• - - - PAT authentication method

Workaround:

• Using BigQuery direct queries as primary data source (works fine via BigQuery MCP connector)
• - Using Chrome browser (Claude in Chrome) to access Tableau Cloud directly for visual dashboard data

Impact:

• Cannot automate Tableau-based reporting workflows through Cowork
• - Requires manual browser-based workaround for accessing Tableau data
• - - All other MCP connectors (BigQuery, Notion, Slack, Linear) work correctly, isolating the issue to the Tableau connector specifically

Note: This bug was reported via Cowork's Claude assistant on behalf of the user (rio.choi@daangn.com).