Behaviour, by design.

BJ Fogg's behaviour model (B=MAT) is a precision instrument for the *moment* of action. A behaviour happens when motivation, ability, and a trigger converge at the same instant — and Fogg's threshold curve makes the trade-offs concrete: if ability is low you'd better not need much motivation, and a trigger arriving on the wrong side of the curve is wasted. It's the lens a designer needs when they're asking why a single tap didn't happen.

Nir Eyal's Hook model picks up where Fogg stops. Once a single action happens, four bound moments — trigger, action, variable reward, investment — turn that action into a loop. Variable reward is the engine, but investment is the *flywheel*: the more a user has put in, the more they're set up to come back, because what they've put in is sitting there waiting. The four-step loop is also what makes Hook auditable — you can name which step is weak.

Hatched declares both on each framework-registry feature surface. Fogg tells you whether a single act is plausible at all (motivation_target, ability_target, trigger_type, trigger_class). Hook tells you whether the act becomes a loop (action_minimization, reward_variability, reward_class, investment_type). When the Planner Behaviour tab renders the Fogg scatter and the Hook quadrant side by side, a feature that looks fine in one view but dim in the other is exactly the case a behaviour designer needs to see.