billing-review
Installation
SKILL.md
Billing Review (Polar)
The handle is the diff. The evidence is where the change breaks a billing invariant the team enforces in review.
Not a general code review. The other lenses know Polar's conventions, contract and deploy shape. This one knows how the billing domain is supposed to behave.
Distilled from ~210 review comments François (frankie567) left on billing PRs between
February and August 2026, plus domain invariants raised by pieterbeulque, psincraian,
joebon and Yopi on the same PRs. Each rule cites its PR.
Read .agents/skills/polar-billing.md first. That is the map of the domain — entities,
services, tasks, the cycle flow, proration, dunning, the ledger. This file is the checklist
that assumes it.