OpenAI's GPT-5.5 is here, and it's no potato: narrowly beats Anthropic's Claude Mythos Preview on Terminal-Bench 2.0
After months of rumors and reports that OpenAI was developing a new, more powerful AI large language model for use in ChatGPT and through its application programming interface (API), allegedly codenamed "Spud" internally, the company has today unveiled its latest offering under the more formal name GPT-5.5. And to likely no one's surprise, it's hardly a "potato" in the disparaging sense of the word: GPT-5.5 retakes the lead for OpenAI in generally available LLMs, coming ahead of rivals Anthropic's and Google's latest public offerings, and even beating the private Anthropic Claude Mythos Preview model narrowly on one benchmark (essentially a statistical tie). "It’s definitely our strongest model yet on coding, both measured by benchmarks and based on the feedback that we’ve gotten from trusted partners, as well as our own experience," explained Amelia "Mia" Glaese, VP of Research at OpenAI, in a video call with journalists ahead of the launch earlier today. OpenAI positions GPT-5.5 as a fundamental redesign of how intelligence interacts with a computer's operating system and professional software stacks. "What is really special about this model is how much more it can do with less guidance," said OpenAI co-founder and president Greg Brockman on the same call. "It’s way more intuitive to use. It can look at an unclear problem and figure out what needs to happen next." Brockman proceeded to emphasize the areas in which users can expect to see gains from using GPT-5.5 compared to OpenAI's prior state-of-the-art model, GPT-5.4, which remains available (for now) to users and enterprises at half the API cost of its new successor. "It’s extremely good at coding," Brockman said of GPT-5.5. "It’s also great at broader computer work, computer use, scientific research—these kinds of applications that are very intelligent bottlenecks." OpenAI CEO and-cofounder Sam Altman also weighed in on the launch and the company's philosophy in a post on X, writing, in part: "We want our users to have access to the best technology and for everyone to have equal opportunity." The model is available in two variants: GPT-5.5 and GPT-5.5 Pro, distinguished by the latter offering enhanced precision and specialized logic for handling the most rigorous cognitive demands. While the standard version serves as the versatile flagship for general intelligence tasks, the Pro model is architected specifically for high-stakes environments such as legal research, data science, and advanced business analytics where accuracy is paramount. This premium tier provides noticeably more comprehensive and better-structured responses, supported by specialized latency optimizations that ensure high-quality performance during complex, multi-step workflows. Unfortunately for third-party software developers, API access is not yet available for either GPT-5.5 nor GPT-5.5 Pro and will be coming "very soon," according to the company's announcement blog post. "API deployments require different safeguards and we are working closely with partners and customers on the safety and security requirements for serving it at scale," OpenAI writes. For the time being, GPT-5.5 is available only to paying subscribers of the ChatGPT Plus ($20 monthly), Pro ($100-$200 monthly), Business, and Enterprise users, with GPT-5.5 Pro access starting at the Pro tier and upwards. A focus on agency At the core of GPT-5.5 is a focus on "agentic" performance—specifically in coding, computer use, and scientific research. Unlike its predecessors, which often required granular, step-by-step prompting to avoid "hallucinating" a path forward, GPT-5.5 is designed to handle messy, multi-part tasks autonomously. It excels at researching online, debugging complex codebases, and moving between documents and spreadsheets without human intervention. One of the most significant technical leaps is the model's efficiency. While larger models typically suffer from increased latency, …