How AI Agents Actually Work: Architecture, Planning, and Failure Modes
Most agent failures are architecture failures. The model gets blamed when a task goes sideways, but nine times out of ten, the real problem is that nobody thought hard enough about how planning, tool use, and reflection should fit together. You can swap in a better model and still get the same crashes — because the scaffolding around the model was never designed to handle what the model was being asked to do.
This post is a practical guide to how agents actually work under the hood: what the core components are, where plans go wrong, how reflection loops help (and when they hurt), and what multi-agent systems look like when you're building them for production rather than demos.
