Purchase Approval

Purchase Approval is the pre-spend decision gate. It answers one question, is this purchase allowed under the supplied procurement policy, and it answers it deterministically. It never moves money; spend and the payment rails own execution, and this skill's sealed decision is what a caller carries into that flow.

Procedure

1. Native data.digest binds the exact purchase request and procurement policy before any judgment.
2. Deterministic rules apply in order: the vendor must be in approved_vendors, the request currency must match the policy currency, and the amount must fit both remaining_budget and single_purchase_cap. The first failed rule refuses with a named refused_reason.
3. An in-policy amount that reaches approval_threshold returns needs_human with the policy's human_lane (default procurement-review); approval below the threshold is approved.
4. A policy missing any required authority field refuses with missing_policy_authority and findings; nothing is inferred or invented.

spend_executed is always false. The decision packet carries both input digests so a downstream spend can prove which request and policy were decided.

Output

purchase_approval (runx.purchase_approval.v1) carries decision (approved, refused, needs_human), reason, vendor, amount, currency, ceiling_amount, human_lane, refused_reason, policy_refs, validation, and the two digests.

Inputs are purchase_request and procurement_policy.