Preflight Checklist
What's Wrong?
Bug Description
The GitHub MCP plugin (plugin:github:github) fails to connect with HTTP 400 from https://api.githubcopilot.com/mcp/.
Environment
- Claude Code version: 2.1.150
- OS: macOS
- Auth:
gh CLI with copilot, gist, read:org, repo, workflow scopes
Error
Failed to reconnect to plugin:github:github: HTTP 400 at https://api.githubcopilot.com/mcp/
Root Cause (diagnosed)
Manually curling the endpoint with an empty payload returns:
malformed payload: invalid message version tag ""; expected "2.0"
The plugin appears to be sending a request without the required "jsonrpc": "2.0" field.
A correct JSON-RPC 2.0 initialize request to the same endpoint returns HTTP 200 successfully,
confirming the endpoint and account are fine — the bug is in the plugin's request construction.
Steps to Reproduce
- Enable GitHub MCP plugin in Claude Code settings
- Authenticate with
gh auth login --scopes copilot,gist,read:org,repo,workflow
- Run
/mcp — plugin fails with HTTP 400
What Should Happen?
The plugin appears to be sending a request without the required "jsonrpc": "2.0" field.
A correct JSON-RPC 2.0 initialize request to the same endpoint returns HTTP 200 successfully,
confirming the endpoint and account are fine — the bug is in the plugin's request construction.
Error Messages/Logs
Failed to reconnect to plugin:github:github: HTTP 400 at https://api.githubcopilot.com/mcp/
Steps to Reproduce
- Enable GitHub MCP plugin in Claude Code settings
- Authenticate with
gh auth login --scopes copilot,gist,read:org,repo,workflow
- Run
/mcp — plugin fails with HTTP 400
Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
No response
Claude Code Version
2.1.150
Platform
Anthropic API
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
No response
Preflight Checklist
What's Wrong?
Bug Description
The GitHub MCP plugin (
plugin:github:github) fails to connect with HTTP 400 fromhttps://api.githubcopilot.com/mcp/.Environment
ghCLI withcopilot,gist,read:org,repo,workflowscopesError
Failed to reconnect to plugin:github:github: HTTP 400 at https://api.githubcopilot.com/mcp/
Root Cause (diagnosed)
Manually curling the endpoint with an empty payload returns:
The plugin appears to be sending a request without the required
"jsonrpc": "2.0"field.A correct JSON-RPC 2.0
initializerequest to the same endpoint returns HTTP 200 successfully,confirming the endpoint and account are fine — the bug is in the plugin's request construction.
Steps to Reproduce
gh auth login --scopes copilot,gist,read:org,repo,workflow/mcp— plugin fails with HTTP 400What Should Happen?
The plugin appears to be sending a request without the required
"jsonrpc": "2.0"field.A correct JSON-RPC 2.0
initializerequest to the same endpoint returns HTTP 200 successfully,confirming the endpoint and account are fine — the bug is in the plugin's request construction.
Error Messages/Logs
Steps to Reproduce
gh auth login --scopes copilot,gist,read:org,repo,workflow/mcp— plugin fails with HTTP 400Claude Model
None
Is this a regression?
Yes, this worked in a previous version
Last Working Version
No response
Claude Code Version
2.1.150
Platform
Anthropic API
Operating System
macOS
Terminal/Shell
Terminal.app (macOS)
Additional Information
No response