GPT-5.6 Sol
GPT-5.6 Sol is OpenAI's flagship model in the GPT-5.6 family, offering advanced reasoning, coding, biology, and cybersecurity capabilities with max reasoning and ultra sub-agent mode. Available on ChatGPT, Codex, and the OpenAI API, it launched July 9, 2026, after a brief national-security review, with an August 2026 update improving accuracy and an Ultrafast tier on Cerebras hardware reaching up to 14× Standard speed. API pricing is $4 per 1M input and $20 per 1M output tokens, with promotional rates through November 21, 2026.