rig-rmcp

MCP (Model Context Protocol) tool support for Rig, built on the rmcp SDK. Depends on rig-core only.

• McpTool — one MCP server tool; convert it into a rig_core::tool::DynamicTool (From) and register it wherever dynamic tools go (rig-agent's AgentBuilder::dynamic_tool, ToolServer::dynamic_tool, or any other runtime). The dynamic tool carries a liveness probe bound to the MCP transport, so registries can retire it on disconnect. tools_from_server converts a whole tool list.
• McpClientHandler<S: rig_core::tool::ManagedToolSink> — an rmcp client handler that keeps a tool registry in sync with notifications/tools/list_changed. rig-agent's ToolServerHandle implements ManagedToolSink, so McpClientHandler::new(client_info, tool_server_handle.clone()).connect(transport) is the agent usage; other runtimes implement the sink for their own registry.
• Per call, an rmcp::model::Meta placed in the runtime's rig_core::tool::ToolContext is forwarded as the request's _meta, and the response's structuredContent, Meta, and raw CallToolResult are published to the context's result map for hooks (preserve_mcp_result).

The rig facade re-exports this crate as rig::tool::rmcp behind its rmcp feature.

Native-only: rmcp's ClientHandler requires Send + Sync unconditionally, which rig's wasm tool registry cannot satisfy; building for wasm32 fails with a single explanatory compile_error!.