Transport behaviours.

Transports are message-level, not socket-level: they move encoded JSON-RPC binaries between a session/connection process and the remote peer.

Server side

A server session holds a sink — {module, term} — and calls Noizu.MCP.Transport.Server.send_message/3 on it for every outbound message. routing.related_request_id identifies the inbound request that caused the message (progress notifications, server-initiated requests made mid-call, and the final response), which the Streamable HTTP transport uses to pick the right SSE stream. stdio ignores routing.

Client side

A client connection owns a transport process implementing Noizu.MCP.Transport.Client. The transport delivers inbound traffic to its owner as:

{:mcp_transport, transport_pid, {:message, binary, meta}}
{:mcp_transport, transport_pid, {:up, info}}
{:mcp_transport, transport_pid, {:down, reason}}