Codex Setup Guide (VS Code)

Search "Codex" in VS Code extension marketplace and install the first official OpenAI plugin.

Click the settings icon in Codex panel, select "Open config.toml", and configure as below.

model_provider = "codex"
model = "gpt-5.1-codex"
disable_response_storage = true
model_reasoning_effort = "medium"
windows_wsl_setup_acknowledged = true

[model_providers.codex]
name = "codex"
base_url = "/api/v1"
wire_api = "responses"
requires_openai_auth = true

Create an auth.json file in the same directory as config.toml with your platform API Key.

Create auth.json in the .codex directory:

{
  "OPENAI_API_KEY": "your-api-key"
}

Return to Codex panel and click "Use API Key" to activate.