codex-stdio-to-uds
Traditionally, there are two transport mechanisms for an MCP server: stdio and HTTP.
This crate helps enable a third, which is UNIX domain socket, because it has the advantages that:
- The UDS can be attached to long-running process, like an HTTP server.
- The UDS can leverage UNIX file permissions to restrict access.
To that end, this crate provides an adapter between a UDS and stdio. The idea is that someone could start an MCP server that communicates over /tmp/mcp.sock. Then the user could specify this on the fly like so:
codex --config mcp_servers.example={command="codex-stdio-to-uds",args=["/tmp/mcp.sock"]}
Unfortunately, the Rust standard library does not provide support for UNIX domain sockets on Windows today even though support was added in October 2018 in Windows 10:
https://github.com/rust-lang/rust/issues/56533
As a workaround, this crate leverages https://crates.io/crates/uds_windows as a dependency on Windows.