Codex setup guide

Install Codex, add your API key, and start a conversation through Starsg.

ImportantBefore you start, prepare an API Key created in the console. If you don't have one yet, follow the link to create it.

1. Environment check

If you use the npm commands below, first run node --version in a terminal. If the command is not found, visit the Node.js download page and install Node.js. Open a new terminal, then run both checks below.

bash

node --version
npm --version

Official installation guides: Codex CLI

Install only the tool you want to use; skip any tool you already have. npm commands:

bash

npm i -g @openai/codex@latest

Important: run the --version command for the tool you installed to check the installation.

bash

codex --version

A version number means the installation worked. If the command is not found, reopen your terminal and try again.

2. Configure Codex

Edit ~/.codex/config.toml — this file holds the gateway endpoint, model defaults and reasoning effort:

toml

disable_response_storage = true
model = "gpt-5.5"
model_provider = "novamaas"
model_reasoning_effort = "high"
model_verbosity = "high"

[features]
web_search_request = true

[model_providers.novamaas]
base_url = "https://api.starsg.ai/v1"
name = "novamaas"
requires_openai_auth = true
wire_api = "responses"

Then write your API key into ~/.codex/auth.json:

json

{
  "OPENAI_API_KEY": "sk-abc...xyz"
}

Note: If a configuration file or its folder is missing, create it before pasting the example above. On Windows, your home folder is %USERPROFILE%.

3. Verify

Run codex in a terminal. A chat reply confirms the connection.