Installing & building
System requirements
| Requirement | Details |
|---|---|
| Operating systems | macOS 12+, Ubuntu 20.04+/Debian 10+, or Windows 11 via WSL2 |
| Git (optional, recommended) | 2.23+ for built-in PR helpers |
| RAM | 4-GB minimum (8-GB recommended) |
DotSlash
The GitHub Release also contains a DotSlash file for the Codex CLI named codex. Using a DotSlash file makes it possible to make a lightweight commit to source control to ensure all contributors use the same version of an executable, regardless of what platform they use for development.
Build from source
# Clone the repository and navigate to the root of the Cargo workspace.
git clone https://github.com/openai/codex.git
cd codex/codex-rs
# Install the Rust toolchain, if necessary.
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
source "$HOME/.cargo/env"
rustup component add rustfmt
rustup component add clippy
# Install helper tools used by the workspace justfile:
cargo install --locked just
# DotSlash fetches pinned development tools such as buildifier on first use.
cargo install --locked dotslash
# Install nextest for the `just test` helper.
cargo install --locked cargo-nextest
# Build Codex.
cargo build
# Launch the TUI with a sample prompt.
cargo run --bin codex -- "explain this codebase to me"
# After making changes, use the root justfile helpers (they default to codex-rs):
just fmt
just fix -p <crate-you-touched>
# Run the relevant tests (project-specific is fastest), for example:
just test -p codex-tui
# `just test` runs the test suite via nextest:
just test
# Avoid `--all-features` for routine local runs because it increases build
# time and `target/` disk usage by compiling additional feature combinations.
Tracing / verbose logging
Codex is written in Rust, so it honors the RUST_LOG environment variable to configure its logging behavior.
The TUI records diagnostics in bounded local stores by default. Set log_dir explicitly to enable a plaintext TUI log for a run:
codex -c log_dir=./.codex-log
tail -F ./.codex-log/codex-tui.log
The non-interactive mode (codex exec) defaults to RUST_LOG=error, but messages are printed inline, so there is no need to monitor a separate file.
See the Rust documentation on RUST_LOG for more information on the configuration options.