As someone who finds a huge amount of enjoyment in developing using Opus 4.6 in Claude code, I’d love to know what other harnesses people use that deliver the same experience as CC. CC is a vibe-coded mess, but it works very well for me.

I do a lot of work in R and find codex (5.4 & 5.3-codex) just totally drop the ball with R. Anthropic’s models are far better with R, so I use them.

But I do wonder how much the harness affects performance.

Would GPT-5.3-Codex perform just as well if it was plugged into CC?