What GPT-5.4 Is
GPT-5.4 is the fusion of advanced reasoning with the coding capabilities of GPT-5.3-codex — the specialized model OpenAI previously used separately for programming tasks. Instead of having two models that complement each other, there is now one that does both well.
Think of it as a Swiss Army knife that finally has a good blade. Swiss Army knives always had many tools, but the main knife was mediocre. GPT-5.4 is the version where the main blade actually got sharp.
The Number That Changes the Conversation
GPT-5.4 is 33% less likely to make errors in individual factual claims than GPT-5.2, and full responses are 18% less likely to contain errors overall. That might sound like cold statistics, but in practice it means less hallucination, less invented information, less rework for those who use the model professionally.
For an analyst using AI to draft reports, or a developer asking for code explanations, that error reduction is not trivial. It's the difference between trusting the answer and always having to verify everything from scratch.
1 Million Token Context
The model supports context windows of up to 1 million tokens. To put that in perspective: a 300-page book contains around 100,000 words. With 1 million tokens, you can process something between 5 and 10 complete books in a single session.
In practice, this opens possibilities that were previously theoretical: analyzing entire codebases, processing extensive legal contracts, reviewing technical documentation for complex products without losing prior context.
Native Computer Use
One of the most talked-about additions is native computer use capability — in Codex and the API, GPT-5.4 is the first general-purpose OpenAI model capable of interacting with graphical interfaces, clicking buttons, filling out forms, and navigating systems as if it were a human user.
This positions GPT-5.4 as a real automation agent, not just an assistant that generates text about what to do. It can execute.
GPT-5.4 Thinking: The Version That Reasons Out Loud
There is a variant called GPT-5.4 Thinking that shows the reasoning plan before responding. It's not just the final result — it's the process. For complex tasks like deep web research, data analysis, or decision-making with multiple variables, seeing the model's reasoning helps identify flaws before they become problems.
This version is available for ChatGPT Plus, Team, and Pro plans.
Tool Search for Agents
Another relevant advance for those building agent systems: GPT-5.4 includes a feature called tool search, which helps the model find and use the right tools within large ecosystems. When an agent has access to dozens or hundreds of tools, knowing which one to use and when is just as important as knowing how to use it.
What to Expect
GPT-5.4 is not the end of the race — OpenAI is already on GPT-5.4 and continues iterating. But it represents the moment when reasoning and coding stopped being a choice and began to coexist natively. For those who use AI in daily work, that is worth paying attention to.