The American AI company OpenAI has released GPT-5.5 and GPT-5.5 Pro, marking a significant shift toward models that act as autonomous agents rather than simple chat assistants. Launched on April 23, 2026, and expanded to the API on April 24, the new model is specifically designed to handle “messy”, multi-part professional tasks with minimal human supervision.
In their announcement, they share that the core breakthrough of GPT-5.5 lies in its agentic reasoning. Unlike its predecessors, it can independently plan workflows, operate software, and move between different digital tools, such as spreadsheets, web browsers, and IDEs.
Despite the increase in reasoning depth, GPT-5.5 maintains the same per-token latency as GPT-5.4. Notably, the model is more token-efficient, requiring fewer total tokens to complete the same complex coding and data analysis tasks. This allows it to deliver higher-quality outputs at a competitive cost.
The model is now the default experience for ChatGPT Plus, Pro, Business, and Enterprise users. The Pro variant, which utilizes parallel test-time compute for higher accuracy, is available exclusively to higher-tier subscribers for the most demanding technical and legal work.
