RAG System

RAG System

When to Use This Skill

• Modifying document retrieval or search behavior
• Tuning relevance scoring or keyword matching
• Working on the context builder for chat
• Adding new query intent types or retrieval strategies
• Debugging "wrong document found" issues
• Extending Phase A/B/C intelligence integration

Architecture Overview

User Query
    │
    ├── Query Classification (classifyQueryIntent)
    │     └── 9 types: requirement, measurement, counting, location,
    │         room_specific, mep, takeoff, daily_report, general
    │
    ├── Primary Retrieval (retrieveRelevantDocuments)
    │     ├── Project isolation (MUST filter by projectSlug)
    │     ├── Role-based access (admin/client/guest)
    │     ├── Keyword extraction with synonym expansion
    │     └── 1000+ point scoring system
    │
    ├── Enhanced Retrieval (twoPassRetrieval)
    │     ├── Pass 1: Precision (exact identifiers)
    │     ├── Pass 2: Notes-first (requirements)
    │     └── Pass 3: Context (keyword matching)
    │
    ├── Cross-Reference Bundling (bundleCrossReferences)
    │     └── Door/window tags, detail callouts, schedule refs
    │
    ├── MEP Retrieval Ordering (mepRetrievalOrder)
    │     └── Schedule → Notes → Plan → Diagram → Spec
    │
    └── Intelligence Enrichment
          ├── Phase A: Title blocks, legends, scales, drawing types
          ├── Phase B: Callouts, dimensions, annotations, symbols
          └── Phase C: Spatial correlation, MEP intelligence

Core Patterns

Project Isolation (Critical Security Pattern)

// lib/rag/document-retrieval.ts — ALWAYS filter by project first
if (projectSlug) {
  const projects = await prisma.project.findMany({
    where: { slug: projectSlug },
    select: { id: true }
  });
  whereClause.projectId = { in: projects.map((p) => p.id) };
} else {
  return { chunks: [], documentNames: [] };  // No project = no results
}

Role-Based Access Control

if (userRole === 'guest') {
  whereClause.accessLevel = 'guest';
} else if (userRole === 'client') {
  whereClause.accessLevel = { in: ['client', 'guest'] };
}
// Admin: no accessLevel filter (sees everything)

Relevance Scoring System

The scoring engine in calculateRelevanceScore() uses additive scoring:

Keyword Extraction with Synonyms

// lib/rag/document-retrieval.ts — extractKeywords()
const synonyms: Record<string, string[]> = {
  'footer': ['footing', 'footer', 'footings', 'foundation', 'base'],
  'rebar': ['rebar', 'reinforcement', 'reinforcing', 'steel', 'bar'],
  'hvac': ['hvac', 'mechanical', 'heating', 'cooling', 'ventilation'],
  'receptacles': ['receptacles', 'outlets', 'duplex', 'plug'],
  // 60+ construction synonym groups
};

Query Intent Classification

// lib/rag/query-classification.ts — classifyQueryIntent()
interface QueryIntent {
  type: 'requirement' | 'measurement' | 'counting' | 'location' |
        'room_specific' | 'mep' | 'takeoff' | 'daily_report' | 'general';
  requiresNotes: boolean;       // Should fetch notes sections
  requiresCrossRef: boolean;    // Should bundle cross-references
  requiresRegulatory: boolean;  // Should fetch regulatory docs
  mepTrade?: 'hvac' | 'plumbing' | 'electrical' | 'fire_alarm';
  roomNumber?: string;
  isTakeoff?: boolean;
  takeoffScope?: string;
}

Two-Pass Retrieval Strategy

// lib/rag/retrieval-strategies.ts — twoPassRetrieval()
// Pass 1: Precision — exact identifiers (sheet numbers, door tags, equipment tags)
const identifiers = extractIdentifiers(query);  // "S-001", "D-101", "AHU-1"

// Pass 2: Notes-first — if query requires specifications/requirements
// Searches for: GENERAL NOTES, STRUCTURAL NOTES, SHALL, REQUIRED

// Pass 3: Context — keyword matching with expanded synonyms
const keywords = extractKeywords(query);

Cross-Reference Bundling

// lib/rag/retrieval-strategies.ts — bundleCrossReferences()
// Scans existing chunks for cross-reference patterns:
// - Door/window marks: /\b[DW]-?\d{1,3}\b/gi
// - Detail callouts: /\b\d+\/[A-Z]-?\d{1,3}\b/gi
// - "See schedule" references
// Then fetches related chunks from the database

MEP-Specific Retrieval Order

For MEP queries, chunks are reordered by priority:

1. Schedule rows (equipment, fixture, panel, lighting)
2. System keynotes and general notes
3. Plan views with equipment tags
4. Diagrams (riser, isometric, one-line, schematic)
5. Specification references

Intelligence Enrichment Phases

Phase A — Title blocks, legends, scales, drawing types:

enrichWithPhaseAMetadata(chunks, projectSlug)
// Adds: titleBlock data, legend entries, dimension data, discipline

Phase B — Callouts, dimensions, annotations:

retrievePhaseBContext(query, projectSlug, chunks)
// Adds context sections: DETAIL CALLOUTS, EXTRACTED DIMENSIONS,
// ANNOTATIONS & REQUIREMENTS, SYMBOL DEFINITIONS

Phase C — Spatial and MEP intelligence:

generateEnhancedContext(query, projectSlug, chunks, corrections)
// Adds: SPATIAL INTELLIGENCE (grid references, sheet matches)
// Adds: MEP INTELLIGENCE (system elements, routing)

Configuration

Key Files

RAG Module Inventory (25 files in lib/rag/)

Anti-Patterns

• Never return documents without project filtering — cross-project leakage is a security violation
• Never skip role-based access control — guests must not see admin documents
• Never hardcode scoring weights inline — use the centralized scoring functions
• Never fetch all chunks at once — use limit parameter and pagination
• Never ignore skipForRag metadata flag — these chunks contain failed extractions

Quick Reference

import { retrieveRelevantDocuments } from '@/lib/rag/document-retrieval';
import { twoPassRetrieval, bundleCrossReferences } from '@/lib/rag/retrieval-strategies';
import { classifyQueryIntent, extractIdentifiers } from '@/lib/rag/query-classification';

// Basic retrieval
const { chunks, documentNames } = await retrieveRelevantDocuments(
  query, 'admin', 12, projectSlug
);

// Enhanced retrieval with two-pass
const { chunks, retrievalLog } = await twoPassRetrieval(
  query, projectSlug, 'admin', 12
);

// Query classification
const intent = classifyQueryIntent("how many receptacles on sheet E-101?");
// → { type: 'counting', requiresNotes: false, requiresCrossRef: true }