interaction-enginelisted

# Interaction Engine ## Mission Make software respond to intent with clarity, continuity, and appropriate energy. ## Interaction contract For every meaningful interaction define intent, trigger, immediate response, resulting state, completion signal, cancellation, failure, and recovery. ## Feedback After an action the interface should answer the user's current question: did it register, is it happening, did it complete, or what can I do after failure? ## Frequency Frequent interactions deserve quiet, fast feedback. Rare interactions may justify richer explanation. Repeated theatrical motion is friction. ## Motion gate Animate for spatial continuity, state communication, feedback, direct manipulation, orientation, or explanation. If motion has no meaningful purpose, omit it. ## Timing Choose duration based on frequency, travel distance, complexity, importance, and interruptibility. Never use one duration globally without considering behavior. ## Easing Direct manipulation should follow input. Transitions should communicate state changes. Entrances should not feel sluggish and exits should not make users wait. ## Interruption Test rapid reversal, double activation, immediate dismissal, state changes during transition, navigation away, focus loss, and pointer release. Avoid visibly restarting from unrelated starting states. ## Direct manipulation For drag/gesture behavior consider pointer capture, ownership, movement mapping, boundaries, resistance, velocity,