AI Backend Engineer · Genpact
Bangalore, India
- Designed idempotent PDF ingest with content hashing and stable chunk IDs so a changed document re-indexes without duplicate vectors or stale citations
- Built authorization-aware hybrid retrieval (pgvector + BM25 + RRF, then cross-encoder rerank) scoped by user and workspace from day one
- Shipped structured answer-with-citations and calibrated abstention as the default path, held on a frozen 40-question set (18 answerable / 11 partial / 11 unanswerable)
- Modeled threats with DFD + STRIDE and ran a separate adversarial suite covering planted instructions, prompt extraction, cross-user access, and hostile PDFs
- Added a bounded LangGraph path only for question types hybrid RAG still failed, with loop limits and a single read-only MCP document-lookup tool
- Built eval gates separating retrieval quality, citation faithfulness, abstention precision/recall, security pass rate, and cost per successful task, with version tags
FastAPI · pgvector · LangGraph · evals