Codex CLI

Quick setup

Run the setup script in a terminal and choose Codex CLI from its list. It finds Codex CLI's settings, checks your API key, and makes the changes described below for you, backing up each file first. It can set up your other agents in the same run.

curl -fsSL https://www.greentokens.io/setup.sh | bash

The script saves your key as the GREENTOKENS_API_KEY environment variable, which Codex CLI reads. Open a new terminal window afterwards so it picks it up.

Add GreenTokens as a provider

Codex CLI supports custom model providers in its config file. Add GreenTokens and make it the default:

model = "gpt-6-sol"
model_provider = "greentokens"

[model_providers.greentokens]
name = "GreenTokens"
base_url = "https://api.greentokens.io/v1"
env_key = "GREENTOKENS_API_KEY"
wire_api = "responses"

• base_url includes /v1.
• env_key names the environment variable Codex reads your key from, so the key never sits in the file.
• wire_api = "responses" uses the OpenAI Responses API, which GreenTokens serves.

Run it

export GREENTOKENS_API_KEY="sk-gt-…"
codex

Choosing models

Set model in the config to any model ID from the models page, or override it for one session:

codex --model gpt-6-astra