Run Codex in a sandbox

The Codex CLI (codex) is installed in the ubuntu template. Choose how it signs in, then run a task with codex exec.

Sign inCopy Anchor Link

With an OpenAI API keyCopy Anchor Link

Put the key in the env of the sandbox:

{
  "CODEX_API_KEY": "sk-..."
}

codex exec reads CODEX_API_KEY for each run. For the terminal UI, sign in once with the key: printenv CODEX_API_KEY | codex login --with-api-key. OpenAI recommends an API key for automation, see authentication in the Codex docs.

With a ChatGPT planCopy Anchor Link

Sign in inside the sandbox, over SSH, in one of two ways:

• With a device code: turn on device code sign-in in the security settings of ChatGPT, or of your workspace. Then run codex login --device-auth, open the link on any device, and enter the code.
• With your browser: connect with ssh -L 1455:localhost:1455, then run codex login, and open the link in the browser of your computer. The forward brings the sign-in back to the sandbox.

Codex keeps the sign-in in ~/.codex/auth.json, and each later codex exec in the same sandbox uses it. A persistent sandbox keeps it across pauses. Codex then uses the usage limits of your plan.

With the open models of Munito AICopy Anchor Link

Put your Munito AI key in the env of the sandbox as MUNITO_API_KEY, and write this configuration to ~/.codex/config.toml in the sandbox, with the files API or a command:

model = "zai-org/glm-5.3-flash"
model_provider = "munito"

[model_providers.munito]
name = "Munito"
base_url = "https://api.munito.ai/inference/v1"
env_key = "MUNITO_API_KEY"
wire_api = "responses"

Codex with open models explains the provider, the model metadata and the regional hosts.

Run a taskCopy Anchor Link

curl -sS --fail-with-body "https://api.munito.ai/sandboxes/v1/sandboxes/$SANDBOX/exec" \
  -H "Authorization: Bearer $MUNITO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"command": "cd /workspace && codex exec --skip-git-repo-check --dangerously-bypass-approvals-and-sandbox \"Write a Python script that prints the first 10 primes, and run it\"", "timeout": 1800}'

• codex exec runs one task and exits. It writes its progress to standard error and its last message to standard output.
• --dangerously-bypass-approvals-and-sandbox lets Codex run commands and change files without asking, and without its own sandbox: the sandbox of Munito AI isolates it. Without it, codex exec can only read files.
• --skip-git-repo-check lets Codex work in a folder that is not a Git repository. In a cloned repository, leave it out.
• --json prints each event of Codex as one line of JSON. With "stream": true in the command, the events come as they happen.
• A command runs for at most 30 minutes. For a longer task, run codex exec in the background with nohup and read its log with later commands.

Use the terminal UI over SSHCopy Anchor Link

Add your public key with SSH, connect with the command that GET /sandboxes/{sandbox_id}/ssh answers, and run codex in /workspace. For a session that outlives your connection, install tmux (apt-get install -y tmux) and start Codex inside it.