Mihaly Csikszentmihalyi catalogued the preconditions of Flow across chess players, mountain climbers, musicians, and surgeons. The conditions generalise: a task just above current skill, immediate feedback, the possibility of failure, clear goals — and an environment that does not interrupt.
Interruption is the default flow-killer. Push notifications, modal dialogs, context switches, unexpected UI movement. Each one breaks the loop between hand and thought and resets the warm-up cost.
Fluera is designed around flow preservation. No notifications during writing. Toolbars auto-hide. Input latency is held under 15 ms because latency above that threshold is itself a form of interruption. The AI is silent unless summoned. Every interface decision is evaluated against a single question: does this help or hurt the loop?