Worried AI will quietly eat your engineering org? In the past two weeks (high‐signal Reddit threads around 2025‐12‐06), senior engineers using Claude Opus 4.5, GPT‐5.1 and Gemini 3 Pro say state‐of‐the‐art LLMs already handle complex coding, refactoring, test generation and incident writeups—acting like a tireless junior—forcing a shift from “if” to “how fast.” That matters because mechanical coding is being commoditized while value moves to domain modeling, system architecture, production risk, and team leadership; firms are redesigning senior roles as AI stewards, investing in platform engineering, and rethinking interviews to assess AI orchestration. Immediate actions: treat LLMs as core infrastructure, invest in LLM engineering, domain expertise, distributed systems and AI security, and redraw accountability so senior staff add leverage, not just lines of code.