OpenAI: GPT-5.3-Codex

GPT-5.3-Codex, OpenAI's advanced agentic coding model, demonstrates strong overall performance, particularly in specialized domains. It typically performs among the fastest models, ranking in the 61st percentile for speed, though it tends to be positioned at premium pricing levels (15th percentile). The model exhibits exceptional reliability, achieving a 100% success rate across all benchmarks, indicating minimal technical failures. Its core strength lies in coding and knowledge-based tasks. It achieved a remarkable 96.0% accuracy in the Coding (Baseline) benchmark, placing it in the 97th percentile, and perfect 100.0% accuracy in General Knowledge, where it was noted as the most accurate model at its price point and among models of similar speed. The model also shows strong reasoning capabilities (96.0% accuracy, 86th percentile) and robust instruction following (88.0% accuracy, 95th percentile). A notable strength is its low hallucination rate, with 98.0% accuracy, suggesting a strong ability to acknowledge uncertainty. While its Email Classification accuracy (97.0%) is solid, its percentile ranking (41st) suggests some room for improvement compared to peers. Its Mathematics performance (93.0% accuracy, 71st percentile) is also commendable. Overall, GPT-5.3-Codex excels in complex, multi-faceted tasks requiring deep understanding and precise execution, aligning with its description as an agentic coding model optimized for long-running workflows and professional knowledge work.