CONF-013: Legacy initialize handshake and version negotiation

Severity	Applies to	Spec section
error	legacy era, stdio, http	2025-11-25/basic/lifecycle#initialization

Opens two fresh sessions (a new process on stdio, a new session on HTTP). handshake: initialize asking for 2025-11-25 must return protocolVersion, a capabilities object and serverInfo (the server MUST respond with its own capabilities and information); an Mcp-Session-Id, if assigned, MUST be visible ASCII; notifications/initialized MUST get no reply (HTTP: 202 Accepted); and a tools/list (or ping) MUST then work. negotiation: initialize asking for version 1900-01-01 must not be agreed to: if the server supports the requested version it MUST answer with the same one, otherwise with another version it supports (#version-negotiation). An error answer passes here because the spec's own error-handling example shows one; CONF-021 notes it.

From the command line: mcpprobe checks explain CONF-013. To leave it out of a run, add "CONF-013" to [checks] disable in mcpprobe.toml; to change how much it counts, use severity_overrides.