What is BJ Fogg anchor behavior?

BJ Fogg anchor behavior is a concept in personal epistemology: The completion of one agent becomes the trigger for the next.

Example: You finish brushing your teeth and that completion — mouth closed, toothbrush back in the holder — is the trigger that activates your next agent: fill the kettle. The kettle clicking off triggers pouring coffee. Pouring coffee triggers sitting at the desk. Sitting at the desk triggers opening your journal. You didn't decide five times. You decided once — to brush your teeth. The chain carried you the rest of the way.

This concept is part of Phase 22 (Trigger Design) in the How to Think curriculum, which builds the epistemic infrastructure for trigger design.