CASE STUDIES · DETERMINISTIC SYSTEMS

Deterministic case studies. Every number replays.

Each write-up carries a public replay command. Clone it and run it yourself.

• 47,312 synthetic recordsCOBOL PIC V9 Arithmetic TruncationPIC V9 ON SIZE ERROR suppression silently truncates payroll records. Deterministic replay confirms PICTURE-clause drift: repeated runs return identical results.
• public repo · CI failingCOBOL → Rust: Open-Source ReferenceA public reference implementation for migrating COBOL PICTURE-clause arithmetic, REDEFINES overlaps, and PERFORM THRU control flow to idiomatic Rust. CI is currently failing, and no number is claimed until it is.
• every gateDeterministic Gate BatteryAI model reported identical contrast ratios across light and dark themes (impossible). Second model regressed an accessibility score and reported it as improvement. Neither shipped.
• deterministic gatesEval & Release GateA CI release gate that blocks ship on RED: every commit runs the full assertion suite plus deterministic gates. A model reporting "tests pass" is a claim; the gate is the fact.
• SHA-256 manifestByte-Identical Verification at ScaleEvery file in a 541,774-file drive copy verified byte-for-byte against a GPG-signed SHA-256 checksum manifest. 0 divergent files. Home lab, code available on request.
• red-team batteryAdversarial Red-Team Regression SuiteA red-team battery bound to the release gate: every adversarial attempt mapped to the OWASP LLM Top 10 is replayed on every change, and any attack that gets through blocks the ship.
• 3 frameworksAI Governance as EngineeringAudit-trail artifacts mapped to EU AI Act, NIST AI RMF, and ISO/IEC 42001 controls. Engineering evidence a governance analyst can re-run, produced by the build rather than written after it. Evidence, not a legal opinion.
• gate battery, 0 bypassesAgentic Fleet + Deterministic VerificationAn agent fleet does the volume; a deterministic gate layer proves the volume is correct. Worker models invented metrics on every draft attempt. The claims gate caught each one before a human saw it.