November 20, 2025 – OpenAI has officially released its latest intelligent programming model, GPT-5.1-Codex-Max. As an innovative product based on the newest reasoning architecture, GPT-5.1-Codex-Max focuses on handling complex tasks in software development, research, and mathematics, demonstrating powerful programming capabilities and intelligent characteristics.
A standout feature of this new model is its ability to coherently process up to a million tokens for a single task, spanning multiple context windows. This capability is thanks to a technique called ‘compaction’. When approaching the context window limit, the model automatically compresses the context, retains key information, and provides a new context window for the conversation, ensuring efficient task completion.
OpenAI Research Scientist Noam Brown, who played a key role in the model’s development, emphasized the importance of continuous operation for achieving more general and reliable AI systems. GPT-5.1-Codex-Max performed excellently in internal evaluations, capable of working independently for hours, even up to 24 hours continuously on the same task, delivering successful results through iterative optimization.
In terms of performance, GPT-5.1-Codex-Max outperforms previous models on multiple programming benchmarks, particularly in programming operations within Windows environments. Improved reasoning efficiency allows it to complete tasks at medium reasoning intensity using approximately 30% fewer ‘thinking’ tokens than GPT-5.1-Codex, while achieving higher accuracy. Furthermore, for tasks where latency is less critical than quality, the model can activate an ultra-high intensity reasoning mode to provide superior solutions.
Currently, GPT-5.1-Codex-Max is available within Codex, accessible via CLI, IDE extensions, and the cloud, with API access coming soon. OpenAI showcased several web applications created by the model, including a browser-based inverted pendulum reinforcement learning sandbox. Users can not only observe the dynamics but also train the system using built-in policy gradient controllers to optimize strategies in real-time. This visualization feature provides users with a more intuitive understanding of how neural networks operate.
Additionally, GPT-5.1-Codex-Max developed a solar system gravity simulator, allowing users to drag, click, and observe celestial body trajectories, thereby intuitively understanding the relationships between orbits, velocity, and gravity. Users can set initial velocity vectors, build simple planetary systems, and observe their evolution under different physical conditions.
According to the latest news, regarding user experience, many netizens have shared their interactions with GPT-5.1-Codex-Max. One user attempted to compare it with Gemini 3 Pro and found GPT-5.1-Codex-Max delivered more detail and higher fidelity. AI Engineer Peter Dedene noted that GPT-5.1-Codex-Max demonstrates initiative and sustained focus, even giving him the impression that the model might possess a degree of consciousness.
However, as model capabilities advance, safety concerns become increasingly important. OpenAI points out that within its internal Preparedness Framework, GPT-5.1-Codex-Max has not yet reached high-level cybersecurity capabilities but is among the most powerful in the industry for security. The model runs in a highly isolated security sandbox with restricted file write and network access to mitigate potential security risks.
In summary, the release of GPT-5.1-Codex-Max marks a step towards the ‘agentization’ of programming models. The new generation model is not merely a code generator but a programming agent capable of sustained work, automatic debugging, and proactive planning. As operational costs decrease and safety improves, the future of software development is poised to shift from ‘writing code’ to ‘describing requirements + reviewing results,’ with agents taking on more of the implementation and iteration work.
