engineering plugin: github MCP URL api.github.com/mcp returns 404 (not a valid endpoint)

[dkushnikov]

Problem

The engineering plugin ships with a broken GitHub MCP URL in its .mcp.json:

"github": {
  "type": "http",
  "url": "https://api.github.com/mcp"
}

https://api.github.com/mcp is not a valid MCP endpoint. It returns a standard GitHub API 404:

$ curl -sI -X POST https://api.github.com/mcp
HTTP/2 404
content-type: application/json; charset=utf-8

{"message":"Not Found","documentation_url":"https://docs.github.com/rest","status":"404"}

This is distinct from a protected endpoint (which would return 401). The route simply does not exist on api.github.com.

Expected

The GitHub MCP server lives at https://api.githubcopilot.com/mcp/ — this is what the claude-plugins-official/github plugin correctly uses. That endpoint returns 401 Unauthorized (meaning it exists and requires auth), not 404.

Note that this is a different service (GitHub Copilot API, not GitHub REST API) and requires header-based auth with a token, not the same OAuth flow as the other MCP servers in the engineering plugin.

Impact

MCP server fails to connect on Claude Code startup with a generic ✘ failed state. Users cannot tell it's a bad URL vs. an auth issue without manually inspecting the endpoint.

Environment

• Plugin version: engineering@1.2.0
• Claude Code: 2.1.92
• Commit: latest main (477c893) still has the broken URL

Related

Similar pattern reported in #15 (non-existing Slack MCP server URL in another plugin).