René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"bug: `get_me` tool fails without parameters due to empty JSON object `{}` not being accepted as valid input","articleBody":"## Description\n\nThe `get_me` tool is documented as requiring **no parameters**, but when called\nwithout any arguments it returns an error in certain MCP clients. Passing a\ndummy parameter (e.g. `{\"_\": \"\"}`) makes the call succeed.\n\nThis is inconsistent with the tool's own schema declaration and creates friction\nfor any client that strictly follows the declared schema.\n\n## Steps to Reproduce\n\n1. Start the GitHub MCP Server (local or remote).\n2. Call `get_me` with an empty argument object (as the schema says no parameters\n   are required):\n```json\n   {\n     \"jsonrpc\": \"2.0\",\n     \"id\": 1,\n     \"method\": \"tools/call\",\n     \"params\": {\n       \"name\": \"get_me\",\n       \"arguments\": {}\n     }\n   }\n```\n3. Observe the error response.\n4. Retry with a dummy parameter:\n```json\n   {\n     \"jsonrpc\": \"2.0\",\n     \"id\": 2,\n     \"method\": \"tools/call\",\n     \"params\": {\n       \"name\": \"get_me\",\n       \"arguments\": { \"_\": \"\" }\n     }\n   }\n```\n5. Observe that this call succeeds.\n\n## Expected Behavior\n\n`get_me` should succeed when called with an empty arguments object `{}`, since\nthe tool schema declares **no required arguments**.\n\n## Actual Behavior\n\n`get_me` returns an error when called with `{}`. The call only succeeds if a\ndummy/extra parameter is included.\n\n## Root Cause (Hypothesis)\n\nLooking at `pkg/github/context_tools.go`, `get_me` is registered with\n`mcp.NewTool` with no input schema properties. After the recent migration from\n`mark3labs/mcp-go` to the official `modelcontextprotocol/go-sdk`, the SDK may\nbe rejecting a `null` or missing `arguments` field differently than an explicit\n`{}`.\n\nTwo possible causes:\n\n1. **SDK-level validation**: The Go SDK may require `arguments` to be a\n   non-null JSON object. If the client omits the field entirely (or sends\n   `null`), it gets rejected before the handler is invoked.\n2. **Handler-level parsing**: The tool handler may attempt to parse\n   `request.Params.Arguments` and fail on a nil/empty map before returning\n   early for the no-param case.\n\n## Environment\n\n- GitHub MCP Server version: `main` (latest)\n- MCP SDK: `modelcontextprotocol/go-sdk` (post-migration)\n- Transport: stdio / streamable-http (reproduced on both)\n- Client: Claude Code with Local LLM\n\n## Suggested Fix\n\nEnsure the `get_me` handler (and any other zero-parameter tool) gracefully\nhandles both a missing `arguments` field and an explicit empty object `{}`.\nA guard like the following at the top of the handler should suffice:\n\n```go\n// No parameters expected; nothing to parse.\n// Handle both nil and empty arguments map to stay robust.\n```\n\nAlternatively, if this is an SDK-level issue, the tool registration could\nexplicitly set an empty-object schema (`\"properties\": {}, \"type\": \"object\"`)\nto signal that an empty object is valid input, which some validators require.\n\n## Additional Context\n\n- The README documents `get_me` as: _\"No parameters required\"_\n- Other zero-parameter tools (if any) may be affected by the same issue.\n- A workaround is to pass any dummy key, but this should not be necessary.","author":{"url":"https://github.com/doheonlee","@type":"Person","name":"doheonlee"},"datePublished":"2026-06-01T07:51:58.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/2587/github-mcp-server/issues/2587"}