I have a basic "Architect" sub-agent that will do research, ask questions, etc. until we agree. Then it finalises a plan. It managed to drift three times in a single day.
A message looks something like this:
https://gist.github.com/van-sprundel/d7e3b6672da7b25a7029f7075c496f3e
Using Opus 4.6, curious if I'm the only one