Agents as coaches does feel like the right direction to go, if they aren't fully autonomous. The way coaches work is that they provide the tools, hold people accountable, and believe that inside we have the ability to change ourselves.

In the future I wonder if assistive agents will be more focused on drawing out what we need rather than taking ambiguous direction and trying to figure out what is going on. Disambiguation is an important problem to figure out between humans and agents (and humans and humans honestly) but we also need to figure out where on the spectrum from complimentary to competitive we need them to be.

Don Norman's cognitive artifacts concept talks about how we might consider these to be replacements or modifiers. I'd recommend anyone considering this to check the concept out!

https://philosophicaldisquisitions.blogspot.com/2016/09/competitive-cognitive-artifacts-and.html