contract changes arrive as reviewed changes

A written contract and a shipped implementation drift apart in one direction: the implementation wins and the document becomes archaeology. Two practices in this period worked against that.

The first was recorded deviation. An implementation could not follow the written sketch as drawn — the identifier shape in the sketch broke the surface already built against it, and the prose mandated a field the sketch omitted. Both were departures from a document the team had agreed to. Both were flagged in the commit, written into the consumer's contract document, and handed to whoever owns reconciliation. Not absorbed silently, not quietly redefined. A reader of the contract therefore learns what is actually true, which is the only property a contract has.

The second was a rule-by-rule cross-check of one producer's feed against the accrual rule it was supposed to implement. The output was findings, not code: no terminal-status field in the feed, so rows that never completed would still accrue; no idempotency marker on deferred entries, so a resend would accrue twice; plus smaller mismatches between the rule table and its own prose. The audit ended with no changes made, which is the correct outcome when the defect sits in the producer's contract and not in the consumer's handling.

Cost: documentation work that ships no feature, and findings that stay open until another owner acts.

What it proves: the team can tell a contract that changed deliberately from one that was quietly outgrown.