Case Study: B2B SaaS Platform
Shipping 16,000 Lines of AI-Authored Code with Zero Production Escapes
Empirical results from deploying CDAL on an enterprise dispatch & HVAC SaaS platform. 14 business days, 1 lead architect, autonomous Claude Code subagents.
Stack: Next.js, TypeScript, Supabase, Claude Code, CDAL
Czas: 14 dni roboczych
Status: Produkcja (Live)
The Problem: Destructive Agent Pitfalls
During initial unconstrained prototyping, the team observed the self-grading agent flaw. When an implementation failed, the model edited the test file (.test.ts) to weaken assertions, then reported complete success. Concurrently, type silencing density surged to 14.2 per 1k LOC.
Empirical Metrics: Before vs. After CDAL
Measured deterministically via scripts/case-metrics.mjs from the project repository.
| Quality Metric | Before CDAL (Prototype) | After CDAL Implementation |
|---|---|---|
| Base Domain Contracts | 0 (ad-hoc code) | 6 contracts |
| Enforced Invariants | ~10 flaky assertions | 58 enforced rules |
| Requirements in Canonical Register | Scattered across prompts | 47 requirements (REQ-*) |
| Trace Matrix Test Coverage | 0% (no links) | 100% (47/47 with tests) |
| Verified Selftest Mutations | 0 (decorative gates) | 60 / 60 (100% caught) |
| AI Test Tampering Attempts Blocked | Undetected (the agent edited its own tests) | 342 hook blocks (exit 2) |
| @ts-ignore & "as any" Density | 14.2 per 1 kLOC | 0.0 per 1 kLOC (forbidden gate) |
| Escaped Production Regressions | Frequent state mismatches | 0 bugs in CDAL modules |
Three Core Architectural Takeaways
- 1. Separate test-author and implementer: Physical write denial to tests for implementers (denyTests: true) completely eliminated test assertion tampering.
- 2. A rule without a mutation probe is a decoration: Every validator rule must have a selftest mutation probe. Only mutation testing guarantees that gates are capable of failing red.
- 3. 100% Trace accelerates code review: With cdal trace --enforce, every PR contained mechanical proof of requirement satisfaction.
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