Update April 25, 2026:
GPT-5.5 and GPT-5.5 Pro are now both available through OpenAI's Responses and Chat Completions API, each with a one million token context window. "Agents built with GPT-5.5 can plan, gather context, call tools, recover from ambiguity, and complete longer workflows with less guidance," OpenAI writes. GPT-5.5 Pro is designed for "higher-accuracy work," the company says.
Independent testing lab Artificial Analysis has already benchmarked GPT-5.5: OpenAI's new model takes the overall top spot by a slim margin over Anthropic's Claude and Google's Gemini, but shows a notable weakness with hallucinations. Effective API costs run about 20 percent higher than GPT-5.4, according to the lab—the doubled token prices on paper are partially offset by lower token usage per task.
Original article from April 23, 2026:
OpenAI has announced GPT-5.5, an agentic model designed to handle complex tasks autonomously across multiple tools. On paper, it's double the API price.
