This at a high level is the right approach. Taking this concept to the next level is in the details. Tiered planning, enforcing context boundaries, and feedback loops are a few key components. Applying the same engineering disciplines to your system/harness that you applied before AI was a thing is the fundamental unlock. The hard part is applying these disciplines in a simple and effective way, while avoiding unnecessary complexity.

If it becomes a tangled web of interconnected components that is hard to follow and anticipate how changes in one part will propagate throughout it, you end up in the same mess every experienced engineer has seen in their career in "that app". The legacy one that sits at the core of the system, riddled with bad neighborhoods that people are afraid to venture into. I suspect that people will end up making the same basic mistakes that were made in "that app". Lots of features and functionality will be added due to unbridled enthusiasm, and will yield a lot of value quickly. At some point, it will become so complex, that simple changes will start causing all sorts of unanticipated downstream effects, and untangling them will create new unintended effects. The classic unwinding of mess that spirals that eventually results in people coming to the conclusion that the system just needs to be rewritten. Time will tell.