Json Rpc 2 0 Message Protocol With Bidirectional Request Response Semantics

via “json-rpc 2.0 message protocol with bidirectional request-response semantics”

Specification and documentation for the Model Context Protocol

Unique: Uses JSON-RPC 2.0 as the foundational message layer with explicit support for server-initiated requests (not just client-initiated), enabling true peer-to-peer capability negotiation and dynamic tool/resource discovery without polling. The protocol maintains a single source of truth in TypeScript schema definitions that are auto-generated into documentation and conformance tests.

More flexible than REST (supports server-initiated requests) and more language-agnostic than gRPC (pure JSON, no code generation required), while maintaining strict schema validation through TypeScript definitions