This seems quite amazing really, thanks for sharing

What is the scope of projects / features you’ve seen this be successful at?

Do you have a step before where an agent verifies that your new feature spec is not contradictory, ambiguous etc. Maybe as reviewed with regards to all the current feature sets?

Do you make this a cycle per step - by breaking down the feature to small implementable and verifiable sub-features and coding them in sequence, or do you tell it to write all the tests first and then have at it with implementation and refactoring?

Why not refactor-red-green-refactor cycle? E.g. a lot of the time it is worth refactoring the existing code first, to make a new implementation easier, is it worth encoding this into the harness?

I do it per feature, not per step. Write the AC for the whole feature upfront, then the agent builds against it. I haven't added a spec-validation step before coding but that's a good idea. Catching ambiguity in the spec before the agent runs with it would save a lot of rework