Flagship models collide: GPT-5.4 Thinking, Claude Opus 4.7, Gemini 3.1 Pro all live

As of April 1–2, OpenAI's GPT-5.4 Thinking, Anthropic's Claude Opus 4.7, and Google's Gemini 3.1 Pro stand as the latest public flagship models. Anthropic also launched a cybersecurity-focused "Claude Mythos Preview" for select customers.