GitHub API error: Unprocessable Entity

[mikhailshilkov]

Describe the bug
I'm trying to use the GitHub MCP server to list/search issues. However, it fails with

Error executing code: MCP error -32603: GitHub API error: Unprocessable Entity

To Reproduce
Steps to reproduce the behavior:

1. Add a GitHub MCP (pointing to its Docker image)
2. Ask Claude to search for issues in a repo.

Expected behavior
Claude finds issues.

Logs

{"jsonrpc":"2.0","id":4989,"error":{"code":-32603,"message":"GitHub API error: Unprocessable Entity"}}
{"jsonrpc":"2.0","id":5002,"error":{"code":-32603,"message":"Invalid arguments: 2.labels.1.description: Expected string, received null, 3.labels.1.description: Expected string, received null, 5.labels.1.description: Expected string, received null, 6.labels.1.description: Expected string, received null, 7.labels.1.description: Expected string, received null, 8.labels.1.description: Expected string, received null, 9.labels.1.description: Expected string, received null, 10.labels.1.description: Expected string, received null, 12.labels.1.description: Expected string, received null, 16.labels.2.description: Expected string, received null, 17.labels.1.description: Expected string, received null, 23.labels.1.description: Expected string, received null, 28.labels.1.description: Expected string, received null, 29.labels.1.description: Expected string, received null"}}

Additional context
It seems to be complaining about empty label descriptions. I tried adding descriptions to all labels but it didn't immediately solve the problem, got a similar one with a milestone:

{"jsonrpc":"2.0","id":5568,"error":{"code":-32603,"message":"Invalid arguments: 28.milestone.description: Expected string, received null"}}

[txbm]

Can you try it again without Docker on this branch: #434 ? Let me know if it's still happening.

[mikhailshilkov]

@txbm Yes, it seems to work on your fork!

[txbm]

Okay that's great news because I think this issue is being reported in several places so now I can be sure my fix works thank you! Hopefully it will get merged soon

[apappascs]

there is a bug in a few methods of github server for: list_issues, update_issue, add_issue_comment, and get_issue tools where their return schema is not following the specification https://github.com/modelcontextprotocol/specification/blob/main/schema/schema.json#L80
this PR is fixing those issues #396