Claude Sonnet 4.5 - The New Coding King? (Sonnet 4.5 vs. GPT 5 Codex)

Anthropic has just released Claude Sonnet 4.5 and it's a BEAST! Definitely looking like it's the new coding king - at least according to the benchmarks. It's a laser focused LLM (super fast) that simply gets the job done. But I want hands on testing to know if Claude Sonnet 4.5 is truly the best in practice. So in this video, I do a live comparison building out a complex feature with Sonnet 4.5 in Claude Code and GPT 5 Codex in Codex at the same time. Anthropic/OpenAI are not sponsoring this video - results and opinions from my testing are genuine!