Codex CLI

Codex CLI is OpenAI's official command-line coding assistant, best paired with the gpt-5.5 model.

Manage multiple providers

If you use the official OpenAI account alongside several gateways, CC Switch is much easier than editing config.toml by hand.

Install

# pick one
npm install -g @openai/codex
brew install codex

Verify:

codex --version

Configure

Edit ~/.codex/config.toml (%USERPROFILE%\.codex\config.toml on Windows). Create it if it doesn't exist:

model = "gpt-5.5"
model_provider = "tokone"

[model_providers.tokone]
name = "TokOne"
base_url = "https://api.tokone.ai/v1"
wire_api = "responses"

wire_api must be responses

Codex CLI uses OpenAI's Responses API (not Chat Completions). Getting wire_api wrong returns unsupported endpoint.

Provide your API Key

Pick one:

Option A: codex login (recommended)

codex login
# paste sk-xxx when prompted

Credentials are written to ~/.codex/auth.json and persist across terminal sessions.

Option B: environment variable

macOS / Linux

export OPENAI_API_KEY="sk-xxx"

Windows Terminal

$env:OPENAI_API_KEY = "sk-xxx"

The env-var approach only affects the current terminal session. To persist it, add it to ~/.zshrc (macOS) / ~/.bashrc (Linux) / Windows system environment variables.

Verify

codex "Describe this project in one sentence"

A reply means it works. You can also confirm the request landed on the "Usage" page of the TokOne console.

FAQ

unsupported endpoint

wire_api is wrong. It must be responses, not chat_completions.

Config changes don't take effect

Make sure model_provider exactly matches the xxx in [model_providers.xxx] (case-sensitive). Codex looks up the provider block by this field at startup.

Model name returns 404

Write the full model name: gpt-5.5, not codex or gpt-codex.

Different keys per project

~/.codex/config.toml is global. To use a different key per project, drop a .codex/config.toml in the project directory to override it (Codex reads the nearest one).

Next steps

• Models — pricing and context for gpt-5.5
• API Endpoints — protocol notes