## Why The `non_prefixed_mcp_tool_names` feature should be applied where MCP tools become model-visible, not by remapping names later in core. Keeping the decision in `McpConnectionManager` construction makes `ToolInfo` the single shaped view that spec building, deferred tool search, routing, and unavailable-tool placeholders can consume directly. This also preserves the existing external behavior while the feature is off, and keeps the feature-on behavior for code mode and hooks explicit at the manager boundary. ## What Changed - Add `McpToolNameMode` to `codex-mcp` and flow it through `McpConfig` into `McpConnectionManager::new`. - Normalize MCP `ToolInfo` names in the manager using either legacy-prefixed namespaces or non-prefixed namespaces; the legacy path adds `mcp__` without restoring the old trailing namespace suffix. - Remove the core-side MCP name remapping path so specs, tool search, session resolution, and unavailable-tool placeholder construction use the manager-provided `ToolName` values directly. - Keep code mode flattening on the `__` namespace separator. - Preserve hook compatibility by giving non-prefixed MCP hook names legacy `mcp__...` matcher aliases. - Add/adjust integration and unit coverage for non-prefixed code-mode behavior, hook matching with the feature on and off, and manager-level legacy prefixing. ## Testing - `cargo test -p codex-mcp --lib` - `cargo test -p codex-core --lib tools::spec::tests -- --nocapture` - `cargo test -p codex-core --lib mcp_tools -- --nocapture` - `cargo test -p codex-core --lib mcp_tool_exposure -- --nocapture` - `cargo test -p codex-core --test all mcp_tool -- --nocapture` - `cargo test -p codex-core --test all search_tool -- --nocapture` - `cargo test -p codex-core --test all hooks_mcp -- --nocapture` - `cargo test -p codex-core --test all code_mode_uses_non_prefixed_mcp_tool_names_when_feature_enabled -- --nocapture` - `cargo test -p codex-tools` - `cargo test -p codex-features`
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.