Files
codex/codex-rs/stdio-to-uds/README.md
Ruslan Nigmatullin 97d4b42583 uds: add async Unix socket crate (#18254)
## Summary
- add a codex-uds crate with async UnixListener and UnixStream wrappers
- expose helpers for private socket directory setup and stale socket
path checks
- migrate codex-stdio-to-uds onto codex-uds and Tokio-based stdio/socket
relaying
- update the CLI stdio-to-uds command path for the async runner

## Tests
- cargo test -p codex-uds -p codex-stdio-to-uds
- cargo test -p codex-cli
- just fmt
- just fix -p codex-uds
- just fix -p codex-stdio-to-uds
- just fix -p codex-cli
- just bazel-lock-check
- git diff --check
2026-04-20 15:59:05 -07:00

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Markdown

# 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 uses `codex-uds`, which provides a cross-platform async UDS API backed by https://crates.io/crates/uds_windows on Windows.