The company rolled out Claude Sonnet 4.5, a new frontier model it claims can code like a seasoned engineer, and maybe even better. Unlike earlier AI tools that were good for quick prototypes, Anthropic says Sonnet 4.5 is reliable enough to build production-ready apps. The timing is classic AI one-upmanship: Sonnet 4.5 lands barely two months after Claude Opus 4.1. Does Anthropic’s Claude Sonnet 4.5 autonomous coding capability represent a genuine breakthrough toward AI replacing junior developers, or are these 30-hour coding marathons still impressive demos that can’t match human judgment on complex projects? Should developers view AI coding assistants like Claude as tools that augment their work, or as competitive threats that will fundamentally reshape the software development job market?