Momentum

Momentum is what happens after the start. It is the flywheel: hard to spin up, and in some architectures, genuinely hard to stop.

Momentum only receives a signal once something actually launches. That is why it can sit fully intact and completely invisible behind a gate that will not open. The person who could not start for three hours is often the same person who cannot stop at midnight.

The range

Lower
Easy to redirect and easy to stop, which makes you flexible in interruption-heavy environments. The trade is that every interruption is a full restart, so one starting problem quietly becomes many across a broken-up day.
Higher
Once moving you absorb friction and multiply output, and small interruptions bounce off. The costs are the lock: stopping is its own struggle, and momentum without a course check can carry you a long way down the wrong road.

What it is not

Not Sustained Effort
Momentum is staying in motion within a session once launched. Sustained Effort is coming back across days and weeks as novelty fades. You can have either one without the other, and the fixes are different.
Not the start
Momentum never explains how a task began. That belongs to Starting Gate and the keys that open it. Judging someone's starting by their cruising speed misses the entire mechanism.

Getting me moving is the whole war. After that I am unstoppable, which is why nobody believes the war exists.

the reaction we design for