Really enjoyed this one!

The envelope pattern is spot on, normalizing the entry point before any business logic touches it feels obvious in hindsight, but almost nobody lays that foundation from day one. And it's far from over-engineered: it's exactly what lets you add WhatsApp or a CLI tomorrow without rewiring everything.

The other thing I like a lot is treating the policy engine as a first-class component from the start. For a system that acts in your name, making trust an architectural responsibility rather than scattered if/else checks after the fact changes everything. Looking forward to the next one!