Retrieval trace failure
- Symptom
- Expected chunk ranks #14 with max_score 0.61 below threshold 0.72
- Root cause
- Embedding model swap without corpus reindex; namespace still on legacy vectors
- Remediation
- Re-embed corpus, tune top_k=12, rerun faithfulness gate on canary
Config evidence
- • embedding: text-embedding-3-large@v2
- • top_k: 8→12
- • score_threshold: 0.72
Trace / metric evidence
- • retrieve_span max_score 0.61
- • recall@10: 0.41 → 0.29
- • Langfuse trace: filter tenant_id=acme-prod
Why this answer won: Hard trace + config evidence beat generic RAG tutorials; tier-1 expert moment paired with observability gap contract.
Rejected: Deprioritized: shallow “what is embeddings” segment without retrieve span scores.