What
When probing an HTTP MCP server for discovery support, a reply carrying the wrong request id or one that fails to decode now resolves cleanly and the server is treated as predating the discovery protocol, instead of hanging or throwing.
Details
- Outcomes are reported as
id-mismatchormalformed; the synthesised errors are namedMcpProbeIdMismatchErrorandMcpProbeMalformedReplyError. - Decode failures cover both malformed JSON and schema validation failures.
- Quoted values in the errors are cut at roughly 200 characters with a
… [truncated]marker. - A stream ending early is now distinguished from a send failure via a dedicated stream-end callback.
Evidence
McpProbeIdMismatchError
Strings lifted out of the shipped bundle, so the claim above can be checked against them.