feat(veridical-week6): Project Veridical Week 6 of 12 — Reranker Integration Sprint: Accuracy Breakthrough
VRDCL-ESR-006 | ~4,800 words | CONFIDENTIAL — Executive Steering Committee
Reporting period: Mar 10–16, 2026 | Status: GREEN — Breakthrough Week
HEADLINE: Cohere Rerank v3 production deployment delivers +4.3 pp accuracy lift
- Retrieval accuracy: 88.2% → 92.5% (NORTH STAR TARGET ACHIEVED, 4 weeks ahead)
- A/B test: 50/50 split, 31,600 queries, p < 0.001, Cohen's d = 0.82
- Domain lifts: Legal +5.3 pp, Finance +4.8 pp, Operations +4.2 pp, Compliance +3.8 pp
- Full traffic migration to reranker completed Mar 16 09:00 UTC
METRICS (Week 5 → Week 6):
- Retrieval accuracy: 88.2% → 92.5% (+4.3 pp breakthrough)
- Query latency P95: 1.14s → 1.21s (+0.07s, reranker overhead — within SLA)
- Token cost/query: $0.022 → $0.024 (+$0.002, reranker API cost)
- Document corpus: 968K → 1.06M (+92K, 1.0M milestone crossed)
- Pilot users: 361 → 438 (+77, Operations onboarded — 5 departments)
- Uptime: 99.98% → 99.96% (planned 42-min maintenance for deployment)
BUDGET: $638K / $1.42M (44.9% at 50% schedule), CPI 1.10, SPI 1.04, EAC $1.29M
RISKS: REI 0.09 (lowest of programme), VR-002 CLOSED, VR-001 downgraded to LOW
VISIONARY: Algorithmic Liability — three-layer audit trail (provenance + reranker + LLM)
saves $60–100M retrofit cost; 330–555× return on $180K early investment
HTML: veridical-week6.html (39 KB, dark theme, zero console errors, 8.7s load)
API: 9 endpoints all HTTP 200 (/api/veridical-week6/*, including /ab-test)
REGRESSION: All 10 existing endpoint groups continue returning HTTP 200