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- Feb 5, 202695% CONFIDENCEfrom help.openai.com
GPT-5.3-Codex Released
OpenAI launches GPT-5.3-Codex, its most capable agentic coding model, the first to combine the Codex and GPT-5 training stacks.
- OpenAI launched GPT-5.3-Codex on February 5, 2026, calling it its most capable agentic coding model to date and about 25% faster; it combines GPT-5.2-Codex coding with GPT-5.2 reasoning and professional knowledge[1][3]
- Available on paid ChatGPT plans in the Codex app, CLI, IDE extension and web, with API access coming soon; trained and served on NVIDIA GB200 NVL72 systems[3]
Notable features
- It is the first model to combine the Codex and GPT-5 training stacks, and OpenAI calls it its first model instrumental in creating itself, with early versions used to debug training and diagnose tests[1][3]
- In the API it takes text and image input, with a 400,000-token context window, up to 128,000 output tokens, an August 31, 2025 knowledge cutoff and low, medium, high and xhigh reasoning effort, priced at $1.75 per million input tokens ($0.175 cached) and $14 per million output tokens[2]
- Benchmarks (vs GPT-5.2-Codex): SWE-Bench Pro 56.8% vs 56.4%, Terminal-Bench 2.0 77.3% vs 64.0%, OSWorld-Verified 64.7% vs 38.2%[3]
- It can be steered while working, and built two games autonomously over millions of tokens[3]
- First model classified High capability for cybersecurity under the Preparedness Framework; OpenAI launched a Trusted Access for Cyber pilot and committed $10M in API credits[3]
References 390% CONFIDENCE
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- [1]95%OpenAI Model Release Notes: Introducing GPT-5.3-Codex (February 5, 2026)help.openai.com· Posted Sep 19, 2026· Starts Feb 5, 2026· 33% of score
OpenAI's[2][3] own model release notes date this entry February 5, 2026
- [2]90%GPT-5.3-Codex Model | OpenAI APIdevelopers.openai.com· Added Sep 22, 2026· 34% of score
OpenAI's[1][3] API model page for GPT-5.3-Codex lists low/medium/high/xhigh reasoning effort, a 400,000 context window, 128,000 max output tokens, Aug 31, 2025 knowledge cutoff and $1.75/$14 per 1M tokens.
- [3]85%Introducing GPT-5.3-Codexopenai.com· Added Sep 19, 2026· Starts Feb 5, 2026· 33% of score
OpenAI's[1][2] announcement post, linked from the release note entry.
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