What are the features of GPT-5.5, OpenAI's smartest model yet?

OpenAI released GPT‑5.5, calling it their "smartest model yet". It excels at writing and debugging code, researching online, analysing data, creating documents and spreadsheets, operating software, and moving across tools until a task is finished. It shows improved ability to directly interact with computer interfaces and matches previous models' latency while giving higher intelligence.