3cf737e4e3
## Why When Guardian or the sandbox network proxy detects and denies a network attempt, core cancels the associated execution through `ExecExpiration`. The Windows sandbox capture path was only forwarding the timeout component of that expiration state. As a result, a sandboxed Windows command whose network attempt had already been denied could keep running until its timeout elapsed rather than terminating promptly in response to the denial. This change closes that cancellation-propagation gap for Windows sandbox execution. ## What changed - Added `WindowsSandboxCancellationToken` as the cancellation hook exposed to Windows capture backends. - Extracted the cancellation token from `ExecExpiration` in core and passed it to both the direct and elevated Windows sandbox capture paths alongside the existing timeout. - Updated direct capture to poll for either process exit, timeout, or cancellation and to terminate cancelled processes without reporting them as timed out. - Updated elevated capture to watch for cancellation and send the existing `Terminate` IPC frame to the elevated runner. The watcher parks for 50 ms between checks to bound response latency without a tight busy wait. - Added Windows regression coverage for a long-running PowerShell command: cancellation ends capture before its timeout and does not set `timed_out`. - Added a visible skip diagnostic when that PowerShell-dependent regression test cannot execute, and consolidated the duplicated expiration-policy branch identified in review. ## Security This improves enforcement after a denied network attempt has been attributed to a Windows sandboxed execution: the command no longer remains alive simply because Windows capture lost the cancellation signal. This PR does not claim to make Windows offline mode an airtight no-network or no-exfiltration boundary. It does not introduce AppContainer or change how network denial is detected; it makes an already-detected denial promptly stop the affected sandboxed command. ## Validation ### Commands run - `just fmt` - `cargo test -p codex-windows-sandbox` - `cargo test -p codex-core network_denial` - `cargo clippy -p codex-core -p codex-windows-sandbox --tests --no-deps -- -D warnings` - `just argument-comment-lint -p codex-windows-sandbox -p codex-core` The new capture regression is `cfg(target_os = "windows")`, so Windows CI is the execution coverage for that test path. The local macOS test runs validate the host-runnable crate and core network-denial behavior. --------- Co-authored-by: Codex <noreply@openai.com>
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, use the sandbox subcommand in Codex CLI:
# Uses the sandbox implementation for the current host OS:
# Seatbelt on macOS, the Linux sandbox on Linux, and Windows restricted token on Windows.
codex sandbox [COMMAND]...
# macOS-only diagnostic option
codex sandbox --log-denials [COMMAND]...
codex sandbox also accepts --profile NAME (-p NAME) to layer
$CODEX_HOME/NAME.config.toml onto the base user config for the sandboxed
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
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 becomes 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.