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Document Processor System

An agentic pipeline that ingests a document, classifies its type, extracts structured data, validates the extraction, and routes it to the appropriate handler — with a HITL gate for low-confidence classifications.

Architecture

Document Input
      ↓
[Classifier Agent]
      ↓
  Confidence > 0.85?
  ├── YES → [Extractor Agent]
  └── NO  → [HITL Gate] → Human confirms type → [Extractor Agent]
                                                       ↓
                                               [Validator Agent]
                                                       ↓
                                           Validation passes?
                                           ├── YES → [Router Agent] → Handler
                                           └── NO  → [Error Handler]

Patterns Used

Pattern Where It Appears
Pipeline / Sequential Classify → Extract → Validate → Route
Conditional Routing Confidence-gated HITL; validation pass/fail routing
HITL Gate Human confirms document type when classifier is uncertain

Agent Roles

Agent Role Output
Classifier Identifies document type and confidence {type, confidence, reasoning}
HITL Handler (Simulated) human confirmation of type Confirmed document type
Extractor Extracts structured fields based on document type Structured data dict
Validator Checks extracted data for completeness and consistency {valid, issues}
Router Determines the appropriate handler and sends output there Routed output

Document Types Supported

Type Key Fields Extracted
invoice vendor, amount, date, line_items, due_date
contract parties, effective_date, terms, termination_clause
resume name, email, skills, experience, education

What This Demonstrates

  1. Sequential pipeline pattern with typed stage interfaces
  2. Confidence-gated HITL — low-confidence triggers human review
  3. Conditional routing based on validation results
  4. Schema-based extraction (different schemas per document type)
  5. Graceful error handling and partial results

Implementations

  • LangChain — Chain pipeline with conditional branching
  • LangGraph — State graph with conditional edges for HITL and validation
  • CrewAI — Sequential crew with classification, extraction, and validation tasks
  • ADK — SequentialAgent with conditional subagent routing