Michael Bolin
1265df0ec2
Follow-up to https://github.com/openai/codex/pull/18178, where we called out enabling the await-holding lint as a follow-up. The long-term goal is to enable Clippy coverage for async guards held across awaits. This PR is intentionally only the first, low-risk cleanup pass: it narrows obvious lock guard lifetimes and leaves `codex-rs/Cargo.toml` unchanged so the lint is not enabled until the remaining cases are fixed or explicitly justified. It intentionally leaves the active-turn/turn-state locking pattern alone because those checks and mutations need to stay atomic. ## Common fixes used here These are the main patterns reviewers should expect in this PR, and they are also the patterns to reach for when fixing future `await_holding_*` findings: - **Scope the guard to the synchronous work.** If the code only needs data from a locked value, move the lock into a small block, clone or compute the needed values, and do the later `.await` after the block. - **Use direct one-line mutations when there is no later await.** Cases like `map.lock().await.remove(&id)` are acceptable when the guard is only needed for that single mutation and the statement ends before any async work. - **Drain or clone work out of the lock before notifying or awaiting.** For example, the JS REPL drains pending exec senders into a local vector and the websocket writer clones buffered envelopes before it serializes or sends them. - **Use a `Semaphore` only when serialization is intentional across async work.** The test serialization guards intentionally span awaited setup or execution, so using a semaphore communicates "one at a time" without holding a mutex guard. - **Remove the mutex when there is only one owner.** The PTY stdin writer task owns `stdin` directly; the old `Arc<Mutex<_>>` did not protect shared access because nothing else had access to the writer. - **Do not split locks that protect an atomic invariant.** This PR deliberately leaves active-turn/turn-state paths alone because those checks and mutations need to stay atomic. Those cases should be fixed separately with a design change or documented with `#[expect]`. ## What changed - Narrow scoped async mutex guards in app-server, JS REPL, network approval, remote-control websocket, and the RMCP test server. - Replace test-only async mutex serialization guards with semaphores where the guard intentionally lives across async work. - Let the PTY pipe writer task own stdin directly instead of wrapping it in an async mutex. ## Verification - `just fix -p codex-core -p codex-app-server -p codex-rmcp-client -p codex-shell-escalation -p codex-utils-pty -p codex-utils-readiness` - `just clippy -p codex-core` - `cargo test -p codex-core -p codex-app-server -p codex-rmcp-client -p codex-shell-escalation -p codex-utils-pty -p codex-utils-readiness` was run; the app-server suite passed, and `codex-core` failed in the local sandbox on six otel approval tests plus `suite::user_shell_cmd::user_shell_command_does_not_set_network_sandbox_env_var`, which appear to depend on local command approval/default rules and `CODEX_SANDBOX_NETWORK_DISABLED=1` in this environment.
Codex CLI (Rust Implementation)
We provide Codex CLI as a standalone executable to ensure a zero-dependency install.
Installing Codex
Today, the easiest way to install Codex is via npm:
npm i -g @openai/codex
codex
You can also install via Homebrew (brew install --cask codex) or download a platform-specific release directly from our GitHub Releases.
Documentation quickstart
- First run with Codex? Start with
docs/getting-started.md(links to the walkthrough for prompts, keyboard shortcuts, and session management). - Want deeper control? See
docs/config.mdanddocs/install.md.
What's new in the Rust CLI
The Rust implementation is now the maintained Codex CLI and serves as the default experience. It includes a number of features that the legacy TypeScript CLI never supported.
Config
Codex supports a rich set of configuration options. Note that the Rust CLI uses config.toml instead of config.json. See docs/config.md for details.
Model Context Protocol Support
MCP client
Codex CLI functions as an MCP client that allows the Codex CLI and IDE extension to connect to MCP servers on startup. See the configuration documentation for details.
MCP server (experimental)
Codex can be launched as an MCP server by running codex mcp-server. This allows other MCP clients to use Codex as a tool for another agent.
Use the @modelcontextprotocol/inspector to try it out:
npx @modelcontextprotocol/inspector codex mcp-server
Use codex mcp to add/list/get/remove MCP server launchers defined in config.toml, and codex mcp-server to run the MCP server directly.
Notifications
You can enable notifications by configuring a script that is run whenever the agent finishes a turn. The notify documentation includes a detailed example that explains how to get desktop notifications via terminal-notifier on macOS. When Codex detects that it is running under WSL 2 inside Windows Terminal (WT_SESSION is set), the TUI automatically falls back to native Windows toast notifications so approval prompts and completed turns surface even though Windows Terminal does not implement OSC 9.
codex exec to run Codex programmatically/non-interactively
To run Codex non-interactively, run codex exec PROMPT (you can also pass the prompt via stdin) and Codex will work on your task until it decides that it is done and exits. If you provide both a prompt argument and piped stdin, Codex appends stdin as a <stdin> block after the prompt so patterns like echo "my output" | codex exec "Summarize this concisely" work naturally. Output is printed to the terminal directly. You can set the RUST_LOG environment variable to see more about what's going on.
Use codex exec --ephemeral ... to run without persisting session rollout files to disk.
Experimenting with the Codex Sandbox
To test to see what happens when a command is run under the sandbox provided by Codex, we provide the following subcommands in Codex CLI:
# macOS
codex sandbox macos [--full-auto] [--log-denials] [COMMAND]...
# Linux
codex sandbox linux [--full-auto] [COMMAND]...
# Windows
codex sandbox windows [--full-auto] [COMMAND]...
# Legacy aliases
codex debug seatbelt [--full-auto] [--log-denials] [COMMAND]...
codex debug landlock [--full-auto] [COMMAND]...
Selecting a sandbox policy via --sandbox
The Rust CLI exposes a dedicated --sandbox (-s) flag that lets you pick the sandbox policy without having to reach for the generic -c/--config option:
# Run Codex with the default, read-only sandbox
codex --sandbox read-only
# Allow the agent to write within the current workspace while still blocking network access
codex --sandbox workspace-write
# Danger! Disable sandboxing entirely (only do this if you are already running in a container or other isolated env)
codex --sandbox danger-full-access
The same setting can be persisted in ~/.codex/config.toml via the top-level sandbox_mode = "MODE" key, e.g. sandbox_mode = "workspace-write".
In workspace-write, Codex also includes ~/.codex/memories in its writable roots so memory maintenance does not require an extra approval.
Code Organization
This folder is the root of a Cargo workspace. It contains quite a bit of experimental code, but here are the key crates:
core/contains the business logic for Codex. Ultimately, we hope this to be a library crate that is generally useful for building other Rust/native applications that use Codex.exec/"headless" CLI for use in automation.tui/CLI that launches a fullscreen TUI built with Ratatui.cli/CLI multitool that provides the aforementioned CLIs via subcommands.
If you want to contribute or inspect behavior in detail, start by reading the module-level README.md files under each crate and run the project workspace from the top-level codex-rs directory so shared config, features, and build scripts stay aligned.