Secure Low-Latency Interactive Messaging (SLIM)

This document specifies the Secure Low-Latency Interactive Real-Time Messaging (SLIM), a protocol designed to support real-time interactive AI applications at scale. SLIM provides the transport layer for agent protocols (for example, A2A and MCP), combining gRPC over HTTP/2 and HTTP/3 with secure messaging, group communication, and native RPC semantics. The protocol provides mechanisms for connection management, stream multiplexing, and flow control while maintaining compatibility with existing gRPC deployments and supporting end-to-end encryption via MLS.