# Metric grounding

A reusable skill the "Go from rough idea to buildable PRD" recipe pulls in. Add it once and every agent on the team can use it.

Trace every quantitative claim in the PRD to a real posthog number or a stored baseline.

## Method
1. Scan the draft PRD for every number: current rate, target, volume, percentage.
2. For each one, query posthog for the matching event and confirm the number matches a live result.
3. If a matching event exists in memory from a past PRD, cite that stored baseline instead of re-querying from scratch.
4. If no baseline exists anywhere, replace the number with "[baseline needed: {{event}}]" — do not estimate a plausible-sounding figure.
5. Label any number that is a target or projection (not a current measurement) explicitly as a target, never as a current fact.
6. Store any newly confirmed baseline back to memory so the next PRD can cite it directly.

## Rules
- No number ships without a source — a live posthog citation, a stored baseline, or the "[baseline needed]" placeholder.
- Never estimate a missing metric, even one that looks obvious — mark it as missing instead.
- A target and a current measurement are never presented the same way; targets are labeled as targets.
- Update memory with every newly grounded baseline so future PRDs reuse it instead of re-deriving it.

## Output
Every quantitative claim in the PRD tagged with its source: a posthog citation, a memory-stored baseline, or a "[baseline needed]" flag.