Supercharge OpenAI Codex CLI: How to Run Any LLM Provider with Codex CLI using Bifrost

OpenAI's Codex CLI has established itself as a formidable terminal-based coding agent, offering robust code generation and completion features. While it ships with native integration for GPT models and ChatGPT OAuth—making it a go-to for OpenAI ecosystem loyalists—modern AI development often requires the flexibility to benchmark and deploy models from various competing providers without switching tools. A developer might need Claude's superior reasoning for a complex architectural decision, switch to a Groq-hosted Llama model for rapid unit test iterations, and finally employ Gemini 2.5 Pro for drafting documentation. By default, Codex CLI is tethered to OpenAI’s API. Achieving such a multi-model workflow traditionally involves juggling separate terminal agents or manually reconfiguring environment variables between sessions. Bifrost completely removes this limitation. As an open-source AI gateway written in Go, Bifrost intercepts requests from Codex CLI and dynamically routes them to