Curtis 'Fjord' Hawthorne
63c2ac96cd
## Summary Improve `js_repl` behavior when the Node kernel hits a process-level failure (for example, an uncaught exception or unhandled Promise rejection). Instead of only surfacing a generic `js_repl kernel exited unexpectedly` after stdout EOF, `js_repl` now returns a clearer exec error for the active request, then resets the kernel cleanly. ## Why Some sandbox-denied operations can trigger Node errors that become process-level failures (for example, an unhandled EventEmitter `'error'` event). In that case: - the kernel process exits, - the host sees stdout EOF, - the user gets a generic kernel-exit error, - and the next request can briefly race with stale kernel state. This change improves that failure mode without monkeypatching Node APIs. ## Changes ### Kernel-side (`js_repl` Node process) - Add process-level handlers for: - `uncaughtException` - `unhandledRejection` - When one of these fires: - best-effort emit a normal `exec_result` error for the active exec - include actionable guidance to catch/handle async errors (including Promise rejections and EventEmitter `'error'` events) - exit intentionally so the host can reset/restart the kernel ### Host-side (`JsReplManager`) - Clear dead kernel state as soon as the stdout reader observes unexpected kernel exit/EOF. - This lets the next `js_repl` exec start a fresh kernel instead of hitting a stale broken-pipe path. ### Tests - Add regression coverage for: - uncaught async exception -> exec error + kernel recovery on next exec - Update forced-kernel-exit test to validate recovery behavior (next exec restarts cleanly) ## Impact - Better user-facing error for kernel crashes caused by uncaught/unhandled async failures. - Cleaner recovery behavior after kernel exit. ## Validation - `cargo test -p codex-core --lib tools::js_repl::tests::js_repl_uncaught_exception_returns_exec_error_and_recovers -- --exact` - `cargo test -p codex-core --lib tools::js_repl::tests::js_repl_forced_kernel_exit_recovers_on_next_exec -- --exact` - `just fmt`
Codex CLI (Rust Implementation)
We provide Codex CLI as a standalone, native 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. 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".
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.