Given parent and GP are both using Claude... have you tried Claude? (I say this as someone who has not tried Claude recently. I did try Claude Code when it first came out, though.)

First, it is important for these discussions that people include details like I did. We're all better off to not generalize.

RE: Claude Code, no I haven't used it, but I did do the Anthropic interview problem, beating all of Anthropic's reported Claude scores even with custom harnesses etc.

It's not a dunk that agents can't produce "as fast as can be" code; their code is usually still reasonably fast; it's just often 2-10x slower than can be.