feat(veridical-week5): Project Veridical Week 5 of 12 — Inflection Point: Reranker Evaluation Complete, Embedding Abstraction Deployed

Report: VRDCL-ESR-005 — Project Veridical Week 5 of 12 Executive Status Report
Classification: CONFIDENTIAL — Executive Steering Committee
Date: March 10, 2026 | Reporting Period: Mar 3–9, 2026
Status: GREEN — On Track, Accelerating | Words: ~4,900

Week 5 Key Achievements:
- Embedding abstraction layer deployed (VR-001 downgraded MEDIUM → LOW)
  - 3-vendor hot-swap: OpenAI, Cohere embed-v3, e5-mistral-7b
  - Shadow index failover validated in production (14 min, 1.2% accuracy drop)
- Offline reranker evaluation COMPLETE (decisive results):
  - Cohere Rerank v3: +4.1 pp (p<0.001, n=2,400) → PRIMARY SELECTED
  - Jina Reranker v2: +3.2 pp → BACKUP
  - bge-reranker-v2-m3: +2.8 pp → FALLBACK (self-hosted)
  - Ensemble (Cohere+Jina): +4.6 pp → NOT RECOMMENDED (marginal +0.5 pp)
  - CTO approved vendor shortlist Mar 10 — Week 6 sprint unlocked
- Finance department onboarded (4th pilot dept, 52 users)
- 100% P0/P1 Week 5 objectives met or exceeded

Metrics (all GREEN, Week-over-Week deltas vs Week 4):
- Query Latency P95: 1.14s (↓0.04s) — target ≤1.50s
- Retrieval Accuracy: 88.2% (↑0.8 pp) — target ≥92% by Wk 10
  - Reranker projects 92.3% at Week 6–7 (3 weeks ahead of gate)
  - By domain: Legal 85.5%, Compliance 89.4%, Engineering 89.1%, Finance 87.8%
- Token Cost: $0.022 (↓$0.001) — target ≤$0.035
- Uptime: 99.98% — Corpus: 968K docs (+121K) — Users: 361 (+77, +44% above target)

Budget: $532K of $1.42M (37.5%) | CPI 1.11 | SPI 1.02 | EAC $1.28M ($140K underrun)
Risk: REI 0.11 (↓0.03 from 0.14) | 0 critical | 1 medium (was 2) | 4 low (was 3)

API Endpoints (8, all HTTP 200):
  /api/veridical-week5 (full), /meta, /reasoning, /health, /metrics, /risks, /next-steps, /reranker

HTML: veridical-week5.html (40KB, dark-theme, accuracy trajectory chart, reranker eval cards, zero console errors)

Author: OneFineStarstuff