# stdio Bus

A lightweight process supervisor and message router that forwards NDJSON-framed JSON-RPC messages between IDEs, CLIs and worker processes running agent logic.

stdio Bus is a single-threaded C daemon that supervises worker processes and routes messages between external clients such as IDEs, CLIs and services. It handles NDJSON-framed JSON-RPC messages with session-based routing while remaining agnostic to the protocol semantics of the messages it forwards.

It uses one event loop on epoll or kqueue, has no dependencies beyond libc and POSIX APIs, keeps messages with the same session ID routed to the same worker, and manages backpressure with configurable limits. Pre-compiled binaries are available for macOS, Linux and musl Linux, along with multi-architecture Docker images, and embeddable runtime libraries exist for Rust, Node.js, C++ and Python, with Go planned.

It also offers an MCP server that connects IDE clients to ACP-compatible agents through the bus.

Website: https://stdiobus.com