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.
Introducing GPT-5. 1-Codex-Max, a faster, more intelligent agentic coding model for Codex.
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.
GPT-5. 2-Codex is OpenAI’s most advanced coding model, offering long-horizon reasoning, large-scale code transformations, and enhanced cybersecurity capabilities.
This system card outlines the comprehensive safety measures implemented for GPT‑5. 1-CodexMax.
Teams use Codex with GPT-5. 5 to ship production systems and turn research ideas into runnable experiments.