The Year AI Changed Everything: 8 Defining Moments of 2025

2025 wasn't just another year of incremental AI progress - it was the year AI became infrastructure. Reasoning models that think before they speak. Coding agents that ship production code. If you blinked, you missed a paradigm shift. I've been tracking these developments all year, and I want to distill the noise into the 8 moments that actually mattered - and what they mean for developers heading into 2026. 1. Claude 4 and the Rise of Agentic AI Anthropic's Claude 4 family (Sonnet 4, Opus 4