MCP 2026-07-28: primitives and stateless requests
server primitives
tools
tools/list, tools/call
resources
resources/list, resources/read
prompts
prompts/list, prompts/get
metadata carried by every request
params._meta
io.modelcontextprotocol/protocolVersion
io.modelcontextprotocol/clientCapabilities
io.modelcontextprotocol/clientInfo (SHOULD)
never inferred from
a previous call, process, or connection
one request, one complete decision
1 / client request
JSON-RPC id + method
arguments + current _meta
server/discover is optional
for the client, required on server
2 / server validates
version + capabilities
method-specific params
unsupported version: -32022
no connection state consulted
3 / server result
resultType: complete
serverInfo in result _meta
lists: ttlMs + cacheScope
deterministic item order
The next request repeats the full contract. Transport lifetime is not protocol session state.