Codex

The codex adapter installs and runs the OpenAI Codex CLI directly inside a Taxiway lab.

Quick Start

taxiway up mylab --type codex --repo https://github.com/org/repo
taxiway shell mylab

taxiway shell mylab attaches to the Codex tmux session. Send prompts directly in that session.

The recommended lab path is to route Codex through the lab's LiteLLM sidecar. taxiway up creates the lab LiteLLM key, sidecar, and proxy route. The adapter writes the taxiway-litellm provider and default gpt-5.5 model into Codex's local config during start. Run taxiway observe up separately when you also want Langfuse traces.

Override the lab model with:

taxiway up mylab --type codex --set model=gpt-5.4

The model name should match a Codex model name declared in LiteLLM, such as gpt-5.5, gpt-5.4, gpt-5.4-mini, or gpt-5.3-codex-spark.

Subscription authentication with Codex Pro uses host Codex OAuth converted for LiteLLM. Run the host login once, then let Taxiway prepare the LiteLLM auth file:

codex login
taxiway credentials codex

The host ~/.codex/auth.json file is not copied into labs. Codex labs only receive TAXIWAY_LITELLM_API_KEY and talk to LiteLLM.

Agent CLI

The adapter uses the codex agent, which installs the npm package @openai/codex. The install phase also ensures the bubblewrap Linux sandboxing utility is available, which Codex uses for process isolation.

The verify phase checks codex --version, codex --help, and whether API-key or OAuth credentials are available, without making an API call.

Inspect the Adapter

taxiway describe codex