Released GPT-5.5, a new frontier model for complex professional work, to the Chat Completions and Responses API, and released GPT-5.5 pro for Responses API requests, including through Batch, for tougher problems that benefit from more compute.

GPT-5.5 supports a 1M token context window, image input, structured outputs, function calling, prompt caching, Batch, tool search, built-in computer use, hosted shell, apply patch, Skills, MCP, and web search. GPT-5.5 defaults to medium reasoning effort.