ModelClock
Capability change announced Feb 5, 2026
OpenAI documents a capability change: “Introducing GPT-5.3-Codex Today we’re releasing GPT-5.3-Codex , the most capable agentic coding model to date for complex, real-world software engineering.”
- Hosting route
- First-party API
- Affected scope
- paid ChatGPT plans everywhere you can use Codex: the Codex app, the CLI, the IDE extension, and Codex Cloud on the web
- Replacement
- gpt-5.2-codex
- Announced
- Feb 5, 2026
- First seen by ModelClock
- Oct 8, 2026
What the provider published
learn.chatgpt.com ↗Introducing GPT-5.3-Codex
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.
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