Module mcp_server

Expand description

Runtime-agnostic MCP server support, including optional attachment to ACP sessions. Runtime-agnostic MCP server support.

This module provides infrastructure for serving MCP directly without tying the core SDK to a particular MCP implementation or async runtime. With the unstable_mcp_over_acp feature, the same servers can be attached to ACP session setup requests through the with_mcp_server builder methods.

§Building MCP servers with tools

The agent-client-protocol-rmcp crate provides the builder APIs for MCP tools backed by the rmcp crate.

§Custom MCP Server Implementations

You can implement McpServerConnect to create custom MCP servers:

use agent_client_protocol::mcp_server::{McpConnectionTo, McpServer, McpServerConnect};
use agent_client_protocol::{DynConnectTo, NullRun, Role, role};

struct MyCustomServer;

impl<R: Role> McpServerConnect<R> for MyCustomServer {
    fn name(&self) -> String {
        "my-custom-server".to_string()
    }

    fn connect(&self, cx: McpConnectionTo<R>) -> DynConnectTo<role::mcp::Client> {
        // Return a component that serves MCP requests
        DynConnectTo::new(my_mcp_component(cx))
    }
}

let server = McpServer::new(MyCustomServer, NullRun);

Structs§

McpConnectionTo: Connection information available to an MCP server.
McpServer: A runtime-agnostic MCP server.
McpToolMetadata: Runtime-neutral metadata for an MCP tool.
McpToolRegistry: Runtime-neutral registry for MCP tools.
RegisteredMcpTool: A registered MCP tool that can be dispatched with erased JSON values.

Enums§

EnabledTools: Tracks which tools are enabled.
McpConnectionContext: Describes how an MCP server connection was established.

Traits§

McpServerConnect: Trait for types that can create MCP server connections.
McpTool: Trait for defining MCP tools.

Functions§

tool_fn: Create a stateless function-backed MCP tool and its concurrent runner.
tool_fn_mut: Create a “single-threaded” function-backed MCP tool and its runner.

Type Aliases§

McpToolSchema: JSON Schema object used to describe MCP tool inputs and outputs.