# Codex Litellm Setup > Stand up the LiteLLM gateway and point the Codex CLI at it. Use when someone wants Codex running against a self-hosted gateway instead of calling OpenAI directly, or says "set up the stack", "wire Codex to LiteLLM", or "run the setup". - Skill: `berriai/codex-litellm-setup` (Agent Skill) - Install (CLI): `npx skillmds@latest add berriai/codex-litellm-setup` - Raw SKILL.md: https://api.skillmd.com/api/skills/berriai/codex-litellm-setup/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: BerriAI (https://skillmd.com/u/berriai) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/berriai/codex-litellm-setup --- # Set up Codex against a LiteLLM gateway You are configuring a machine so the Codex CLI sends its requests to a local LiteLLM gateway instead of straight to OpenAI. The gateway holds the real OpenAI key; Codex only ever sees a virtual key you can revoke. `scripts/setup.sh` does the deterministic work. Your job is to get its inputs right, read its output, and fix what it reports. Do not reimplement it with raw `docker` commands; it handles port interpolation, key minting, and config backup in ways that are easy to get subtly wrong. ## Getting the repo You may be handed this task with nothing on disk yet. If you are not already inside the repo, clone it and change into it: ```bash git clone https://github.com/BerriAI/codex-litellm-stack cd codex-litellm-stack ``` If a `codex-litellm-stack` directory already exists, work in it rather than cloning a second copy. Confirm you are at the repo root before going on: ```bash ls scripts/setup.sh docker-compose/docker-compose.yml ``` Every path below is relative to that root. ## Before you run anything Check these and resolve them first, because each produces a confusing failure several steps later: 1. **Docker is running.** `docker info` must succeed. If it doesn't, tell the user to start Docker Desktop; you can't start it for them on macOS. 2. **An OpenAI API key is available.** On a fresh clone, setup creates the ignored `docker-compose/litellm.env` from `litellm.env.example` and prompts for the key. For unattended setup, put the key in that file first. **Never invent, guess, or reuse a key from elsewhere in the conversation**, and don't echo the key back in your reply once you have it. 3. **Port 4000 is free.** Run `lsof -i :4000`. If something holds it, pass `--port ` rather than killing the other process. ## Running it ```bash ./scripts/setup.sh # prompts for the OpenAI key if needed ./scripts/setup.sh -y # unattended; the key must already be in litellm.env ./scripts/setup.sh --port 4123 # different host port ./scripts/setup.sh --enterprise # also emit the fleet config (see codex-litellm-fleet) ``` If you already wrote the key into `litellm.env` yourself, use `-y` so the script doesn't block on a prompt you can't answer. Setup ends by running `scripts/doctor.sh`. Read that output. The "Ready." banner above it means the script finished, not that the connection works. ## What it changed Say this back to the user plainly, because two of these touch files outside the repo: - `docker-compose/litellm.env` got a generated master key, plus the OpenAI key if one was entered. It is now chmod 600. Do not commit it. - `~/.codex/config.toml` was **overwritten**. Any pre-existing config was copied to `config.toml.bak.` first. If the user had settings there they care about (MCP servers, sandbox policy, approval mode), offer to merge them back from the backup. - `~/.codex/fast.config.toml`, `deep.config.toml`, and `astra.config.toml` were installed as current Codex profile files. Existing files with those names were backed up first. - `dist/start-codex.sh` exports `LITELLM_API_KEY` and launches Codex. It contains a live credential and is gitignored. Keep it that way. - On macOS, `~/Library/LaunchAgents/com.codex-litellm-stack.env.plist` was installed and loaded. It puts `LITELLM_API_KEY` into the GUI login session at every login, which is the only way the Codex desktop app can see it. It holds the key in plaintext at chmod 600. `--no-desktop` skips it; `scripts/uninstall-desktop-env.sh` removes it. - Two containers, `litellm` and `postgres`, under the compose project `codex-litellm-stack`. ## Verifying it actually works Don't declare success on exit code alone. Run a real turn: ```bash export LITELLM_API_KEY="$(sed -n 's/^export LITELLM_API_KEY=//p' dist/start-codex.sh | tr -d '"')" codex exec "reply with the word CONNECTED and nothing else" ``` Then confirm the request reached the gateway rather than OpenAI directly: ```bash docker compose -f docker-compose/docker-compose.yml --project-directory docker-compose \ logs litellm --tail 20 ``` You should see a POST to `/v1/responses`. If Codex answered but nothing shows in the gateway log, `~/.codex/config.toml` isn't being read. Check whether `CODEX_HOME` is set to somewhere else. ## The desktop app Nothing extra to run. Setup already installed the LaunchAgent, so `codex app` or the Dock icon works with the same config and key as the CLI. Two things to tell the user, because both look like bugs: - **An app that was already open won't have the key.** It kept the environment it launched with. Quit and reopen it. - **A session's model is fixed when the session starts,** and a custom provider has no in-app model picker. `codex app -c model=gpt-6-astra` sets it at launch; otherwise edit `model` in `~/.codex/config.toml` and start a new session. Verify without opening anything: ```bash launchctl getenv LITELLM_API_KEY # non-empty means the app will find it ``` If the user objects to the key sitting in the login session environment, that is a fair objection. `./scripts/setup.sh --no-desktop` keeps it CLI-only, and `scripts/uninstall-desktop-env.sh` undoes an install. ## Choosing models There are no aliases to configure. The gateway publishes OpenAI's model ids under their own names plus a `"*"` catch-all, so any model id that works against OpenAI works here. Model choice lives entirely on the Codex side: ```bash codex # the default in config.toml codex -m gpt-6-astra # any model, ad hoc codex --profile deep # loads ~/.codex/deep.config.toml ``` Edit `docker-compose/litellm-config.yaml` only to *restrict* what the gateway will serve, or to attach budgets and rate limits to specific models. If you remove the `"*"` entry, every model must then be listed explicitly. ## If something fails Use the `codex-litellm-troubleshoot` skill. Don't guess at fixes; each `doctor.sh` check failure names its own cause.