AI summary
Written by AI from the official notes. Check them for exact details.OpenAI has released GPT-5.3-Codex, enhancing coding capabilities and performance for software engineering.
- GPT-5.3-Codex offers stronger reasoning and professional knowledge.
- Runs 25% faster than GPT-5.2-Codex for Codex users.
- Improved collaboration with real-time progress updates.
- Available in Codex app, CLI, IDE extension, and Codex Cloud.
Why it matters: Software engineers and developers should care for improved coding efficiency and collaboration features.
Full release notes4 changes
Today we're releasing GPT-5.3-Codex, the most capable agentic coding model to date for complex, real-world software engineering.
GPT-5.3-Codex combines the frontier coding performance of GPT-5.2-Codex with stronger reasoning and professional knowledge capabilities, and runs 25% faster for Codex users. It's also better at collaboration while the agent is working—delivering more frequent progress updates and responding to steering in real time.
GPT-5.3-Codex is available with paid ChatGPT plans everywhere you can use Codex: the Codex app, the CLI, the IDE extension, and Codex Cloud on the web. API access for the model will come soon.
To switch to GPT-5.3-Codex:
- In the CLI, start a new thread with:
Or use /model during a session.
- In the IDE extension, make sure you are signed in with ChatGPT, then choose GPT-5.3-Codex from the model selector in the composer.
- In the Codex app, make sure you are signed in with ChatGPT, then choose GPT-5.3-Codex from the model selector in the composer.
- If you don't see GPT-5.3-Codex, update the CLI, IDE extension, or Codex app to the latest version.
For API-key workflows, continue using gpt-5.2-codex while API support rolls out.