Phase D — Evidence, Policy & Cascading Failure#

Overview#

Phase D enforces risk-tiered evidence requirements for each IU and propagates failures through the dependency graph. When evidence fails for an IU, its dependents are re-validated.

Components#

1. Evidence Model (src/models/evidence.ts)#

enum EvidenceKind { TYPECHECK, LINT, BOUNDARY, UNIT_TEST, PROPERTY_TEST, STATIC_ANALYSIS, THREAT_NOTE, HUMAN_SIGNOFF }
enum EvidenceStatus { PASS, FAIL, PENDING, SKIPPED }

interface EvidenceRecord {
  evidence_id: string;
  kind: EvidenceKind;
  status: EvidenceStatus;
  iu_id: string;
  canon_ids: string[];
  artifact_hash?: string;
  message?: string;
  timestamp: string;
}

2. Policy Engine (src/policy-engine.ts)#

Evaluates whether an IU has sufficient evidence for its risk tier.

3. Cascade Engine (src/cascade.ts)#

When IU-X fails, propagates to dependents:

• Dependent IU-Y: re-run typecheck, boundary, relevant tests
• Failure propagation is explicit and graph-based

4. Evidence Store (src/store/evidence-store.ts)#

Persists evidence records bound to IU IDs and canonical nodes.