//! MCP (Model Context Protocol) server — Streamable HTTP transport.
//!
//! Exposes two tools to Agent backends:
//! - `list_agents` — list all registered Agent backends (name + online status)
//! - `call_agent` — forward a message to another Agent and wait for its reply
//!
//! Authentication reuses the existing vtoken Bearer scheme. The calling Agent
//! supplies its own vtoken so the Hub can identify who is calling and which
//! WeChat conversation context (vctx) to attach the exchange to.
pub use mcp_router;
pub use A2aWaiter;