OpenAI Upgrades Codex Coding Agent with Specialized GPT-5-Codex Model

Summary

OpenAI released GPT-5-Codex, a specialized version of GPT-5 designed specifically for its Codex AI coding agent. The new model features dynamic "thinking" capabilities that allow it to spend anywhere from a few seconds to seven hours on a single coding task, adapting compute time to task complexity. OpenAI reports that GPT-5-Codex outperforms the base GPT-5 model on SWE-bench Verified, a benchmark measuring agentic coding abilities, as well as on code refactoring benchmarks drawn from large, est