#Capstone#RAG#ColPali#Neo4j#Hybrid Retrieval#RAGAS#Syllabus

Project 03: LegalRAG — Hybrid Multi-Modal + Graph RAG for Contracts

Build a production legal-document intelligence system combining ColPali multimodal indexing (no OCR), a Neo4j knowledge graph, hybrid retrieval with RRF, cross-encoder reranking, and RAGAS-gated evaluation.

May 28, 2026 at 12:00 PM1 min readFollowFollow (Hindi)

Topics You Will Master

ColPali multimodal page indexing without OCR
A Neo4j knowledge graph over contracts, parties, clauses, obligations, and dates
Hybrid retrieval with BM25 + dense and Reciprocal Rank Fusion
Cross-encoder reranking and adaptive query routing
RAGAS evaluation with a faithfulness gate
Best For

Engineers building enterprise RAG over complex, visually rich documents where answer faithfulness is non-negotiable.

Expected Outcome

A working legal RAG system with an adaptive router, integrated security, and a RAGAS report passing the faithfulness gate.

Project Overview

LegalRAG combines no-OCR multimodal indexing, knowledge-graph retrieval, hybrid search, and a RAGAS-gated evaluation harness into a single legal-document intelligence system.

Objective

Index a contract corpus with ColPali, populate a Neo4j knowledge graph from extracted entities, and build a routed hybrid retrieval pipeline gated by RAGAS faithfulness scores.

Scope

  • ColPali multimodal page indexing (no OCR).
  • A Neo4j knowledge graph with nodes for contracts, parties, clauses, obligations, dates, and amounts.
  • Hybrid retrieval with BM25 + dense and Reciprocal Rank Fusion.
  • Cross-encoder reranking over fused candidates.
  • Adaptive query routing across ColPali, BM25, Neo4j, and the fused stack.

Datasets

  • Commercial-contract corpora with clause categories.
  • Optional multi-jurisdiction legal text.

Stack

  • Multi-vector index with MaxSim (late-interaction) scoring (Qdrant).
  • BM25 sparse retrieval (Elasticsearch).
  • A graph database (Neo4j) with LLM + Pydantic entity extraction.
  • Cross-encoder reranker.
  • PII masking and input/output guardrails.
  • FastAPI + LangChain LCEL + Docker for serving.

Evaluation

  • RAGAS faithfulness, answer relevancy, context precision and recall.
  • Faithfulness gate on golden QA pairs.

Deliverables

  • Indexed corpus across Qdrant, BM25, and Neo4j.
  • Operational hybrid retrieval with RRF and reranker.
  • A working adaptive query router.
  • Integrated PII masking and guardrails.
  • A RAGAS report meeting the faithfulness gate.

Prerequisites

Modules 14–19 (embeddings, RAG basics, advanced RAG, quantization & multimodal RAG, graph/caching/security).

Find this tutorial useful?

Subscribe to our YouTube channels for more practical production walk-throughs.

Discussion & Comments