What has worked better for me is splitting authority, not just prompts. One agent can touch app code, one can only write failing tests plus a short bug hypothesis, and one only reviews the diff and test output. Also make test files read only for the coding agent. That cuts out a surprising amount of self-grading behavior.

It’s not an agentic pattern, it’s an approach to test driven development.

You write a failing test for the new functionality that you’re going to add (which doesn’t exist yet, so the test is red). You then write the code until the test passes (that is, goes green).

I built rlm-workflow which has stage gating, TDD and sub-agent support: https://skills.sh/doubleuuser/rlm-workflow/rlm-workflow

That's the cool bit - you don't have to. CC is perfectly well aware and competent to implement it; just tell it to.