KnownFix MCP Response Inspector
JSON-RPC 2.0 envelope check · Free · Browser-local
Response
Input is not uploaded or saved. Results omit identifiers, payloads and server error messages.
Diagnostic checklist
No response checked.
Response triage
Worked examples and expected results
Synthetic fixtures checked against this tool's current local logic. They are not live connection or delivery tests.
- Result envelope. Envelope structure passes. An empty tool list is not evidence that a useful tool ran.
- Tool-level failure. Envelope structure passes, with a tool-level error flag. Structural success is not task success.
- Result and error together. Needs attention: a response must contain exactly one of result or error.
When to investigate further
- A passing envelope is not a completed task
- Keep the transport status, JSON-RPC result and tool-level outcome separate. The tool-error example is intentionally valid at the envelope layer.
- Streaming frames do not parse
- The inspector expects one JSON object, not HTTP headers, SSE framing, a batch or a whole transcript.