Expand description
MCP protocol version negotiation.
The two MCP eras the ticket serves (SDK-017 R1, the revisions SDK-014 R2
names): 2026-07-28, where every request carries its protocol version and
capabilities in _meta and server/discover answers the server’s
versions; and 2025-11-25, where initialize opens a session scoped to
this process. An initialize asking for any other version is answered
with 2025-11-25, as the MCP lifecycle requires (the server answers a
version it supports and the client decides); a client that cannot speak
it disconnects. A modern request naming an unknown version is refused.
Structs§
- Refusal
- A refusal of a request before its method is looked at.
- Session
- The process’s negotiation state: whether a legacy session was opened.
Enums§
- Era
- The era a request is served in.
Constants§
- LEGACY
- The legacy revision.
- MODERN
- The modern revision.
- SUPPORTED
- The versions the ticket speaks, newest first.
Functions§
- server_
info - What the ticket says it is.
- shaped
- A result shaped for its era: modern results carry
resultTypeand the server’s info in_meta.