Openai models 4 and above don't work with the current 0.24.0 version

[afmjoaa]

For openai models remote mcp server is not working.

Getting the following error:
Error code: 400 - {'error': {'message': "Invalid schema for function 'get_me': In context=(), object schema missing properties.", 'type': 'invalid_request_error', 'param': 'tools[13].function.parameters', 'code': 'invalid_function_parameters'}}

previous issue: #376

The error "Invalid schema for function 'get_me'" indicates that the JSON schema provided for the function named 'get_me' does not conform to the expected format. This typically occurs when interacting with APIs, particularly those involving function calling or structured output, like OpenAI's API.

We are using the MCP server like following:
"github": {
"url": "https://api.githubcopilot.com/mcp/",
"transport": "streamable_http",
"headers": {"Authorization": f"Bearer {os.environ.get('GITHUB_PAT', '')}"},
},

[LevanArabuli]

+1, we're facing the same issue and had to disable Github MCP for some time before the issue gets resolved

[SamMorrowDrums]

Hi @afmjoaa! 👋

I've opened a fix for this issue in #1553. The problem is that the get_me tool's JSON schema was {"type": "object"} without a properties field, and OpenAI strict mode requires properties to be present even when empty.

The fix ensures the schema is {"type":"object","properties":{}}.

To test the fix:

Unfortunately, Docker images aren't automatically built for PR branches. You can test by building from source:

# Clone and checkout the fix branch
git clone https://github.com/github/github-mcp-server.git
cd github-mcp-server
git checkout fix-openai-get-me-schema

# Build the binary
go build -v ./cmd/github-mcp-server

# Run it
./github-mcp-server stdio

Or if you're using Docker, build locally:

git clone https://github.com/github/github-mcp-server.git
cd github-mcp-server
git checkout fix-openai-get-me-schema
docker build -t github-mcp-server:fix-openai .

Then use github-mcp-server:fix-openai as your image.

Would you be able to test this and confirm if it resolves the issue for your OpenAI setup? Thanks!

CC @LevanArabuli

[SamMorrowDrums]

Root Cause Analysis

The regression was introduced by the go-SDK migration (PR #1428). Here's the toolsnap comparison:

Before go-SDK migration (commit ada4bc0)

"inputSchema": {
  "properties": {},
  "type": "object"
}

Current main (after go-SDK migration)

"inputSchema": {
  "type": "object"
}

With fix (PR #1553)

"inputSchema": {
  "type": "object",
  "properties": {}
}

The jsonschema library used by the go-SDK has omitempty tags on struct fields, which causes empty maps like Properties to be omitted during JSON serialization. The fix uses json.RawMessage to explicitly include the properties field.

[SamMorrowDrums]

https://github.com/github/github-mcp-server/releases/tag/v0.24.1 the latest docker image is now released with the change. Updating the remote server shortly.

[SamMorrowDrums]

Remote server now also fixed.

[LevanArabuli]

Thanks @SamMorrowDrums 🙏 ,
I can confirm it works as expected now!