I find the same. We have abstractions with multiple concrete implementations, examples of patterns and examples of anti patterns.

I usually find I can achieve 90% of the outcome I'm trying to achieve. I use sonnet for planning, qwen for coding, sonnet for review.

The harness mattering more than the model lines up with my experience too. What this paper measures is within-turn constraint decay. The version that bites in multi-agent setups is across-session — the architectural rules an agent wrote down on Monday don't reach the agent making the next change on Tuesday.