Describe the bug

When attempting to configure the official GitHub Copilot MCP endpoint (https://api.githubcopilot.com/mcp/) within the mcp.json file for the JetBrains plugin, the connection fails with an HTTP 401 error. The error log explicitly states bad request: missing required Authorization header. This occurs even when a valid Personal Access Token (PAT) is provided in the correct headers object as specified in the documentation. The client does not appear to be sending the Authorization header from the mcp.json configuration to the endpoint. This prevents users from potentially extending or interacting with the native GitHub MCP endpoint directly.

Affected version

GitHub Copilot for Jetbrains: Version 1.5.47-243 (latest, Jun 17, 2025)

Steps to reproduce the behavior

1. In a JetBrains IDE with the GitHub Copilot plugin installed, create or modify the mcp.json file in the configuration directory.
2. Configure the file to point to the GitHub MCP endpoint and include a valid PAT for authentication, like so:

   {
       "servers": {
           "github": {
               "url": "https://api.githubcopilot.com/mcp/",
               "headers": {
                   "Authorization": "Bearer <PAT_TOKEN>"
               }
           }
       }
   }

or

    {
        "servers": {
            "github": {
                "url": "https://api.githubcopilot.com/mcp/",
                "authorization_token": "Bearer <PAT_TOKEN>"
            }
        }
    }

3. Restart the IDE and observe the GitHub Copilot logs.
4. See the connection error in the logs.

Expected vs actual behavior

Expected: The GitHub Copilot client in the JetBrains IDE should read the mcp.json configuration, attach the specified Authorization header to its POST request, and successfully connect to the https://api.githubcopilot.com/mcp/ endpoint.

Actual: The connection fails. The logs show an HTTP 401 error with the message bad request: missing required Authorization header, indicating that the header configured in mcp.json was not included in the request sent by the client.

Logs

[2025-06-19 10:10:02.001][info]    [github]Starting server github
[2025-06-19 10:10:02.236][error]   [github]Connection state: Error: Error POSTing to endpoint (HTTP 401): bad request: missing required Authorization header

[2025-06-19 10:10:02.236][info]    [github]Connection state: Stopped
[2025-06-19 10:10:02.236][error]   [github]Failed to connect to MCP server: Error POSTing to endpoint (HTTP 401): bad request: missing required Authorization header

[2025-06-19 10:10:02.237][error]   [github]message: Error POSTing to endpoint (HTTP 401): bad request: missing required Authorization header
 stack: Error: Error POSTing to endpoint (HTTP 401): bad request: missing required Authorization header

    at JY.send (C:\snapshot\copilot-client\node_modules\@modelcontextprotocol\sdk\src\client\streamableHttp.ts:414:15)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)