GPT 5.3 Codex
Released on February 5, 2026
Release Summary
OpenAI's latest coding-focused model with best-in-class coding performance (57% SWE-Bench Pro, 76% TerminalBench 2.0, 64% OSWorld). Features customizable personality modes ('pragmatic' or 'friendly'), mid-task steerability with live updates, and the first model to achieve 'high' rating for cybersecurity on OpenAI's preparedness framework. Significantly faster and more efficient—uses less than half the tokens of 5.2-Codex for equivalent tasks and runs >25% faster per token.
Timeline
GPT-5.3 Codex released
OpenAI releases GPT-5.3 Codex with customizable personality modes, top coding benchmarks, and first 'high' cybersecurity rating on preparedness framework.
Codename 'Garlic' leaked
Internal codename and 400K context window specs surface in developer communities, suggesting a focus on efficiency over scale.
Model IDs found in tooling
References to GPT-5.3 model identifiers discovered in OpenAI's code and API tooling by external developers.
GPT-5.2 enterprise launch
Limited enterprise rollout of GPT-5.2, setting the stage for public 5.3 release speculation.