OpenAI has released two AI “reasoning” models that it says are its most capable yet as well as an open-source AI agent that helps computer programmers code, as the company seeks to gain a lead over its rivals. The open-source coding agent, called Codex CLI, marks the first time since 2019 that OpenAI has introduced a significant open-source tool.

OpenAI on Wednesday announced new reasoning AI models, o3 and o4-mini which can pause and work through questions before responding.