I've basically lived inside Claude Code for the last few months. Opus 4.8 is my daily driver and I'm not looking to leave it. But when xAI dropped Grok 4.5 on July 8, two things nagged at me enough that I wanted it in the exact same terminal I already had open.
This is the write-up of that afternoon — what pulled me in, the three lines that actually did the job, and where I landed on Grok vs Opus after living with both for a week.
Why I even bothered
Two reasons, and neither of them is "it's the smartest model in the world," because it isn't.
One: it's built for coding. Grok 4.5 is the first xAI model explicitly aimed at coding and agentic work — xAI says it was trained on real developer sessions from Cursor, so the pitch is "long stretches of work inside an actual repo," which is exactly what Claude Code does all day.
