Files
codex/codex-rs
Michael Bolin 5eab9ff8ca app-server: expose thread permission profiles (#18278)
## Why

The `PermissionProfile` migration needs app-server clients to see the
same constrained permission model that core is using at runtime. Before
this PR, thread lifecycle responses only exposed the legacy
`SandboxPolicy` shape, so clients still had to infer active permissions
from sandbox fields. That makes downstream resume, fork, and override
flows harder to make `PermissionProfile`-first.

External sandbox policies are intentionally excluded from this canonical
view. External enforcement cannot be round-tripped as a
`PermissionProfile`, and exposing a lossy root-write profile would let
clients accidentally change sandbox semantics if they echo the profile
back later.

## What changed

- Adds the app-server v2 `PermissionProfile` wire shape, including
filesystem permissions and glob scan depth metadata.
- Adds `PermissionProfileNetworkPermissions` so the profile response
does not expose active network state through the older
additional-permissions naming.
- Returns `permissionProfile` from thread start, resume, and fork
responses when the active sandbox can be represented as a
`PermissionProfile`.
- Keeps legacy `sandbox` in those responses for compatibility and
documents `permissionProfile` as canonical when present.
- Makes lifecycle `permissionProfile` nullable and returns `null` for
`ExternalSandbox` to avoid exposing a lossy profile.
- Regenerates the app-server JSON schema and TypeScript fixtures.

## Verification

- `cargo test -p codex-app-server-protocol`
- `cargo test -p codex-app-server
thread_response_permission_profile_omits_external_sandbox --
--nocapture`
- `cargo check --tests -p codex-analytics -p codex-exec -p codex-tui`
- `just fix -p codex-app-server-protocol -p codex-app-server -p
codex-analytics -p codex-exec -p codex-tui`

---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/18278).
* #18279
* __->__ #18278
2026-04-21 23:52:56 -07:00
..
2026-04-21 17:24:30 +01:00

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

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.