Crate rmcp_mux 

rmcp_mux - MCP Server Multiplexer

A library for multiplexing MCP (Model Context Protocol) servers, allowing a single server process to serve multiple clients via Unix sockets.

Features

• Single server, multiple clients: One MCP server child process serves many clients
• Initialize caching: First initialize response is cached for subsequent clients
• Request ID rewriting: Transparent request routing with ID collision avoidance
• Automatic restarts: Exponential backoff restart of failed server processes
• Active client limiting: Semaphore-based concurrency control

Usage as Library

use rmcp_mux::{MuxConfig, run_mux_server};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let config = MuxConfig::new("/tmp/my-mcp.sock", "npx")
        .with_args(vec!["-y".into(), "@anthropic/mcp-server".into()])
        .with_max_clients(10)
        .with_service_name("my-mcp-server");

    run_mux_server(config).await
}

Usage with Multiple Mux Instances

use rmcp_mux::{MuxConfig, spawn_mux_server, MuxHandle};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    // Spawn multiple mux servers in a single process
    let handles: Vec<MuxHandle> = vec![
        spawn_mux_server(MuxConfig::new("/tmp/mcp1.sock", "server1")).await?,
        spawn_mux_server(MuxConfig::new("/tmp/mcp2.sock", "server2")).await?,
    ];

    // Wait for all to complete (or shutdown signal)
    for handle in handles {
        handle.wait().await?;
    }
    Ok(())
}

Re-exports

pub use config::CliOptions;

pub use config::Config;

pub use config::ResolvedParams;

pub use config::ServerConfig;

pub use runtime::MAX_PENDING;

pub use runtime::MAX_QUEUE;

pub use runtime::health_check;

pub use runtime::run_mux;

pub use runtime::run_mux_internal;

pub use runtime::run_proxy;

pub use state::MuxState;

pub use state::ServerStatus;

pub use state::StatusSnapshot;

Modules

config

Configuration types and loading for rmcp_mux.

runtime

Runtime module for the mux daemon.

scan

state

tray

wizard

Interactive wizard for configuring rmcp_mux services and rewiring MCP clients.

Structs

MuxConfig

Configuration for embedding rmcp_mux in your application.

MuxHandle

Handle for a spawned mux server.

Constants

NAME

Library name

VERSION

Library version

Functions

check_health

Perform a health check on a mux socket.

run_mux_server

Run a mux server blocking until shutdown.

run_mux_with_shutdown

Run mux with external shutdown control.

spawn_mux_server

Spawn a mux server as a background task.