CONF-005: Request ids: null is rejected and responses echo the id exactly¶
| Severity | Applies to | Spec section |
|---|---|---|
| error | both eras, stdio, http | 2026-07-28/basic/index#requests |
Sends a request with id null, which MUST NOT be accepted (an error or no answer both pass; a result fails). Then sends a string id with non-ASCII characters and a large integer id; responses MUST carry the same id, with the same JSON type. The rule is identical in 2025-11-25 (https://modelcontextprotocol.io/specification/2025-11-25/basic#requests). On servers that speak both eras it runs twice: once with modern requests, and once inside a legacy initialize session as
From the command line: mcpprobe checks explain CONF-005. To leave it out of a run, add "CONF-005" to [checks] disable in mcpprobe.toml; to change how much it counts, use severity_overrides.