Developed a unified user authentication and API key management system for the openai/codex repository, focusing on consolidating and securing access across multiple deployment environments. Leveraging JavaScript, TypeScript, and Node.js, the work introduced OIDC-based API key retrieval and a CLI sign-in flow that supports both ChatGPT and existing API keys. The implementation included environment-aware authorization endpoint configuration, enabling seamless adaptation to different deployment contexts. This feature reduced onboarding friction for developers, improved security posture, and streamlined integration for downstream teams. The approach emphasized backend and full stack development, with targeted fixes to stabilize authentication flows and minimize operational overhead.