OpenAI Releases GPT-5.3-Codex: The Most Advanced Agentic Coding Model Powers Its Own Development
On February 5, 2026, OpenAI officially launched GPT-5.3-Codex, its most powerful agentic coding model to date. The model combines cutting-edge coding performance with general reasoning capabilities, supports long-horizon task execution, and played a key role in its own development process.
Core Features and Performance Enhancements
GPT-5.3-Codex merges the coding power of GPT-5.2-Codex with the reasoning and specialized knowledge of GPT-5.2, combining the strengths of both in a single model. Additionally, the model operates 25% faster than its predecessor, excelling at long-horizon tasks such as research, tool use, and complex execution flows.
Pioneering Self-Development Model
GPT-5.3-Codex is the first OpenAI model to play a significant part in its own creation. The development team used early versions for self-training, deployment management, and diagnosing test results. This approach significantly accelerated the model’s development cycle, demonstrating new progress for AI in engineering practices.
Interactivity and Task Execution
The model allows users to provide real-time guidance and interact during tasks without losing context. This colleague-like collaboration enables it to handle complex workflows involving multi-step reasoning and tool calls, including coding, debugging, and a broader range of professional tasks.
Availability and Deployment
GPT-5.3-Codex is now available to paid users via the Codex application, command-line tools, and associated platforms. OpenAI states that the model has set new records on multiple benchmarks, including its performance on agentic coding tasks.
