ν.β D3 CLOSED 2026-05-04 — outcome-VALIDATED-WITH-NOTE
Summary
Spike: D3 — Q-016 Will Update Architecture μ.ε hybrid Phase-1 implementation cost deepening Outcome: outcome-VALIDATED-WITH-NOTE Kill condition: NOT-MET (aggregate £12-20K << £30K threshold) Q-NU-012: frontier-derisked; state 1 → state 3
Key findings
- μ.ε hybrid Phase-1 confirmed at £12-20K / 24-40 engineer-days (+0% to +11% vs Spike 21 £12-18K baseline)
- 6 component cost-rows: C1 PROV-O (£3-5K) + C2 Bitstring Status List (£2-3K) + C3 SHACL (£2-4K) + C4 LinkML+Catala (£1-2K) + C5 VC issuance simplified (£2-3K) + C6 IAS routing (£2-3K)
- Phase-1 simplification: C5 WillCredential VC can use plain JSON-LD + did:web (avoids Sphereon SSI-SDK TypeScript dependency); reduces Phase-1 C5 cost from £4-6K → £2-3K
- All 6 smoke tests passed (30 subprocess-isolated iterations, N=5 per component)
- Phase-1.5+ uplift path: ~£13-23K additional (Sphereon OID4VCI + ProvToolbox + Scotland + Catala GP Connect)
Toolchain limitations (documented)
- Sphereon SSI-SDK: NOT installed → Phase-1 plain JSON-LD fallback; Phase-1.5+ Sphereon integration
- ProvToolbox 2.2.x: NOT installed → rdflib+pyshacl fallback for Phase-1
- Spruce ssi WASM: NOT installed → deferred Phase-1.5+
- nexus-prov: NOT installed → hand-authored SHACL shapes
T-file
~/off-github/library/projects/inherit/T-spike-nu-beta-D3-q016-will-update-implementation-2026-05-04.md
Cascade-Q placeholder
~/testatetech/docs-strategy/docs/superpowers/specs/2026-04-29-multi-phase-audit/current-questions/Q-NU-012-q016-will-update-implementation-cost-deepening.md
Upstream evidence
- Spike 21: T-spike-q016-will-update-architecture-pre-validation-2026-05-03.md (μ.ε 22/25 RECOMMENDED)
- T56: witness-event-as-PROV-bundle jurisdiction-agnostic primitive
- T2: Bitstring Status List W3C Rec production-ready [F-VC-03]