server/discover
server/discover - The mandatory discovery RPC introduced in 2026-07-28 (SEP-2575): servers advertise their supported protocol versions, capabilities, and identity, and clients may call it before any other request for up-front version selection or as a backward-compatibility probe on stdio. It replaces the removed initialize handshake.
server/discover is the 2026-07-28 revision's front door. With the
initialize handshake removed, it is the one RPC every server must
implement: it returns the server's supported protocol versions,
capabilities, and identity. Clients can call it first to pick a
version, skip it entirely and self-describe per request through
_meta, or use it as a compatibility probe against stdio servers of
unknown vintage. MCP News uses it the same way: a server/discover
probe that answers grounds an endpoint's revision support first-hand.
Related concepts
Sources and verification
Last verified · confidence 1.00.