The coding tool in a terminal and the service supplying its model can be selected separately. OpenAI's Codex CLI supports custom providers, and OpenRouter's tutorial uses that configuration to send requests through its model-routing service. The setup identifies the provider endpoint, supplies access credentials and selects an exact model identifier. Requests then use OpenRouter's account and billing. The guide describes a way to retain Codex's coding workflow while changing the model service behind it, including access to models from other developers.
