Introducing GPT-5. 1-Codex-Max, a faster, more intelligent agentic coding model for Codex.
Summary generated by The Flow from the publisher's feed. The full article lives at OpenAI Blog.
GPT-5. 3-Codex is a Codex-native agent that pairs frontier coding performance with general reasoning to support long-horizon, real-world technical work.
GPT‑5. 3-Codex is the most capable agentic coding model to date, combining the frontier coding performance of GPT‑5.
GPT-5. 2-Codex is OpenAI’s most advanced coding model, offering long-horizon reasoning, large-scale code transformations, and enhanced cybersecurity capabilities.
This addendum to the GPT-5 system card shares a new model: GPT-5-Codex, a version of GPT-5 further optimized for agentic coding in Codex. GPT-5-Codex adjusts its thinking effort more dynamically based on task complexity, responding quickly to simple conversational queries or small tasks, while independently working for longer on more complex tasks.
Codex is a cloud-based coding agent. Codex is powered by codex-1, a version of OpenAI o3 optimized for software engineering.
How engineers at Nextdoor use Codex with GPT-5. 5 to investigate hard-to-reproduce issues, build across platforms, and focus on product outcomes.