Building Codex with Tibo Sottiaux

Building and evolving AI coding agents requires a strategic balance between local execution and cloud-based scalability. Codex, an open-source coding harness, demonstrates how prioritizing correctness and efficiency—often through Rust—enables agents to handle complex tasks like automated code reviews and security verification. As models improve, the need for manual "crutches" or complex harnesses diminishes, allowing agents to manage long-running goals and architectural maintenance autonomously. The integration of Codex into ChatGPT highlights the challenges of merging disparate technical stacks while maintaining high performance for millions of users. Ultimately, the future of software development lies in unified, agentic systems that act as personal AGI, capable of managing schedules, data, and proactive code execution, thereby shifting the developer's role from manual coding to high-level architectural intent and system oversight.