Writing Decision Rules

A good Vouch candidate is a small deterministic judgement with explicit input, a stable checked-profile source, and an inspectable output.

At a glance

LISPEX

(define (refund? days opened?) (and (<= days 14) (not opened?)))
(refund? 9 #f)

Result

OUTPUT

#t

Keep host data conversion outside the rule and pin the exact datum passed into the checked profile.
Return a compact value whose interpretation is documented by the application, then test both accepted and rejected boundaries.
Version source, input corpus, and receipts together so replay has an explicit denominator.
Once a decision rule is stable, encode its exact reviewed bytes as a Lispex Image when you need a deterministic visual transport. Keep the ordinary source as the review and version-control surface.

A decision receipt does not decide whether the business policy itself is fair or correct.