OpenAI Launches Codex, a Software Engineering AI Agent

Today, OpenAI introduced a cloud-based software engineering AI agent, powered by the company’s most powerful coding model called ‘codex-1’. It’s available to ChatGPT Pro, Team, and Enterprise users, starting today. OpenAI says ChatGPT Plus and Edu users will get access to Codex in the future.

Talking about Codex, the software engineering agent can perform multiple tasks in parallel on the cloud. It can add new features, answer questions about your codebase, fix bugs, and propose pull requests for review. Developers can connect their GitHub repositories and run the AI agent to perform a variety of tasks. You can access Codex in ChatGPT from the left sidebar.

OpenAI says codex-1 is built on the o3 model by training it “using reinforcement learning on real-world coding tasks in a variety of environments to generate code that closely mirrors human style and PR preferences.“

Codex follows the instructions carefully and runs tests until it receives a passing result in the cloud environment. You can define the AGENTS.md file in your repo to guide the agent so that it can navigate the codebase and perform actions precisely the way you want.

On OpenAI’s internal SWE tasks, the codex-1 model achieves 75% accuracy, more than o3-high which gets 70%. On SWE-Bench Verified, codex-1 does slightly better than o3-high after a number of attempts.

OpenAI finally says the Codex agent operates in a secure, isolated container in the cloud, and during the task execution, internet access is disabled. The agent can’t access external websites, APIs, or other services.