GPT-5.3 Codex (xhigh)

The GPT-5.3 Codex (xhigh) model, developed by OpenAI and released on February 5, 2026, is a specialized artificial intelligence system designed for high-performance coding and reasoning tasks. The model holds an intelligence index of 53.6 and a coding index of 53.1. Performance metrics indicate an output speed of 92.337 tokens per second with a time to first token of 54.938 seconds. Pricing for the model is set at $1.75 per million input tokens and $14.00 per million output tokens, resulting in a blended rate of $4.81 per million tokens. Benchmark results include a GPQA score of 0.915, HLE of 0.399, SciCode of 0.532, IFBench of 0.754, LCR of 0.74, TerminalBench Hard of 0.530, and TAU2 of 0.860.