LexisRAG Legal
Deterministic Legal Intelligence & Hybrid Vector Knowledge Base
“Paralegals spent 15+ hours per diligence audit manually searching clauses across thousands of non-standardized PDF agreements.”
A global advisory group held an archive of 100,000+ contracts, indemnification agreements, and regulatory filings.
Searching for precedent clauses during M&A due diligence required cross-referencing multi-hundred-page scanned PDFs with complex tables and scanned addendums.
Traditional enterprise keyword search returned hundreds of irrelevant false positives, while early generative AI tools hallucinated non-existent clauses.
15-Hour Diligence Cycle: Slowed down closing timelines on multi-million-dollar transactions.
Hallucination Risk: Generative tools paraphrased clauses without source page attribution.
Table & Addendum Loss: Scanned PDFs with tables were unsearchable by standard OCR.
Hybrid Dense/Sparse Vector Search with Citation Grounding
A high-precision RAG pipeline combining hierarchical PDF layout parsing, dense vector embeddings, BM25 exact term indexing, and bounding-box citation grounding.
Hierarchical Layout Parser
Extracts clauses, tables, and headers preserving parent document context.
Hybrid Index Core
Executes dense semantic queries and sparse exact keyword searches concurrently.
Attribution Engine
Maps extracted citations back to exact PDF page and bounding box coordinates.
Live Interface & Inspection Workflows
Semantic Query & Clause Attribution Workbench
Interactive clause comparison workspace with side-by-side source PDF highlighting and multi-document attribution.
Air-Gapped Tenant & Policy Configuration
Enterprise access control and tenant isolation interface enforcing strict client matter privilege barriers.
Architectural Trade-Offs
pgvector with HNSW Index Over External Vector SaaS
Enterprise legal compliance required data residency inside the client's existing VPC. pgvector eliminated external third-party data egress while maintaining sub-50ms search times.
Cross-Encoder Reranking Over Raw Similarity Scores
Cosine similarity alone often ranks superficially similar text above semantically critical caveats. Cross-encoder reranking boosted retrieval accuracy from 72% to 96%.
Operational Telemetry
Comprehensive clause discovery per contract set
Direct PDF bounding-box citation grounding
Indexed in scalable pgvector cluster
