Define a metric precisely

Define "{{metric}}" precisely enough that two analysts compute the same number.
It informs: {{purpose}}

Pin the edges: the window, what counts as the event, who is excluded, how to treat
returns and trials, and what timezone the day boundary uses. Every one of those is
somewhere a definition usually goes soft.

Then say what this metric will fail to capture, so nobody over-reads it.

What to fill in

{{metric}}

The metric — e.g. active user

{{purpose}}

What decision it informs — e.g. whether the prompt library is being used