Multimodal AI in 2025: How GPT-5.1, Gemini, Claude, and Grok Learned to Understand Everything

In 2020, AI was an archipelago of isolated models. By 2025, everything has changed. This article is a deep dive into the unified Next Token Prediction paradigm that enabled GPT-5.1, Gemini, Claude, and Grok to understand text, images, and video simultaneously. We break down how it works and what the flagship models are capable of today.