[BUG] Linear MCP OAuth /authorize endpoint redirects to deprecated gdrive install URL

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?

Summary:
The api.anthropic.com/authorize endpoint, when used for Linear MCP OAuth,
redirects to api.anthropic.com/mcp/gdrive/google/install?metadata=... —
which is a deprecated Google Drive MCP install URL that returns "Server Turned Down".
This makes it impossible to authenticate the Linear MCP connector from a
remote web session.

Steps to Reproduce

1. Start a Claude Code web session with the Linear MCP connector configured
2. Call mcp__Linear__authenticate — it returns an OAuth URL of the form:

https://api.anthropic.com/authorize?response_type=code&client_id=...

1. Open that URL in a browser (or via curl)
2. Instead of an Anthropic authorization screen, you are redirected to:

https://api.anthropic.com/mcp/gdrive/google/install?metadata=<hash>

1. That page shows: "Server Turned Down — This MCP server has been turned down."

curl Evidence

Request:
curl -s 'https://api.anthropic.com/authorize?response_type=code&client_id=f43a335a-e6f5-4978-a7fd-574d0933f5ab&code_challenge=...&redirect_uri=http%3A%2F%2Flocalhost%3A60776%2Fcallback&state=...'
Response:
Found. Redirecting to https://api.anthropic.com/mcp/gdrive/google/install?metadata=050903277dda624c5823697fe874e4c98f97a5a653b9c5191ff71c26c90a99df

Expected Behavior

The /authorize URL should render an Anthropic authorization page allowing
the user to approve Linear access and receive a callback code.

Actual Behavior

Permanent redirect to a deprecated Google Drive MCP install endpoint, which
itself returns "Server Turned Down". The OAuth flow is uncompletable.

Impact

Linear MCP cannot be authenticated in any remote Claude Code web session.
All Linear data (live issue status, cycle info, assignees, due dates) is
unavailable. The workaround is using stale HTML snapshots.

Workaround

None available client-side. The redirect happens at the server level
(confirmed via curl — not a browser/cookie issue).

What Should Happen?

The /authorize URL should render an Anthropic authorization page allowing
the user to approve Linear access and receive a callback code.

Error Messages/Logs

The `api.anthropic.com/authorize` endpoint, when used for Linear MCP OAuth, 
redirects to `api.anthropic.com/mcp/gdrive/google/install?metadata=...` — 
which is a deprecated Google Drive MCP install URL that returns "Server Turned Down".
This makes it impossible to authenticate the Linear MCP connector from a 
remote web session.

Steps to Reproduce

Steps to Reproduce

1. Start a Claude Code web session with the Linear MCP connector configured
2. Call mcp__Linear__authenticate — it returns an OAuth URL of the form:

https://api.anthropic.com/authorize?response_type=code&client_id=...

1. Open that URL in a browser (or via curl)
2. Instead of an Anthropic authorization screen, you are redirected to:

https://api.anthropic.com/mcp/gdrive/google/install?metadata=<hash>

1. That page shows: "Server Turned Down — This MCP server has been turned down."

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.9659.0

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_