OpenAI Codex configuration for OpenRouter

OpenAI’s coding & work tool Codex is not tied to OpenAI as a first-party model provider. In particular, it allows OpenRouter to be used - a hub to currently 480 models offered by independent inference providers. These inference providers offer models not found in the OpenAI like OpenAI’s own open-weights models gpt-oss-20b or gpt-oss-120b, or third party models including Gemini, Claude, Grok or GL…