L3:fraud-review-platform · AI Wing · Hero
AI Fraud Document Review
OCR plus a two-pass LLM review of procurement packets, with a risk engine that had to pass its own gates.
- Role
- Creator and sole engineer: designed, directed, reviewed and shipped it with AI coding agents
- Period
- May 2026 to Oct 2026
Results
90.9% to 36.4%
False-positive rate on noisy clean packets
Offline evaluation on a development gold set.
Verified76.2% to 0%
Fail-open rate
Offline evaluation on the same development gold set.
Verified0 of 3,780
Production runs where the shadow engine changed user-visible output
The hybrid engine cut false positives to 9.1% offline, but recall fell to 0.841, so it failed its gate and ran in shadow mode only.
Verified11.1% to 3.7%
Prompt-injection success rate
Live evaluation runs after a model change (false positives also fell from 26.1% to 21.7%); evaluation results, not production outcomes.
Verified
Problem
Procurement teams need fast, trustworthy fraud review of document packets. Early versions raised alarms on clean packets, which erodes trust faster than a missed flag.
What I did
- Built a two-pass pipeline (per-document findings, then a cross-document verdict) over OCR output, with live progress streaming.
- Moved prompts into declarative YAML agents on Microsoft Agent Framework.
- Built gold sets and CI gates for false-positive rate, recall and fail-open, then replaced a majority-vote guardrail and over-broad safe patterns.
- Designed a hybrid rules plus LLM risk engine (rules catalog, severity floors, evidence verifier, duplicate fingerprints) and kept it in shadow mode when it failed the recall gate.
- Handled a secret-exposure incident with a history purge, a zero-downtime two-key rotation and a move to Key Vault references.
Architecture
- HumanProcurement reviewerUploads a document packet
- ClientNext.js web appUpload, live progress, reports
- ServiceFastAPI backendTwo-pass pipeline, live progress
- AIDocument IntelligenceOCR: Read, then Layout
- AIAgent Framework YAML agentsPer-document, then cross-document
- AIAzure OpenAIInputs screened by Prompt Shields
- ServiceHybrid risk engineRules plus LLM, shadow mode
- DataCosmos DB and BlobHistory and reports
Data flow
- Procurement reviewer to Next.js web app (document packet)
- Next.js web app to FastAPI backend (REST, live progress)
- FastAPI backend to Document Intelligence (OCR)
- FastAPI backend to Agent Framework YAML agents (findings, verdict)
- Agent Framework YAML agents to Azure OpenAI (model calls)
- FastAPI backend sends asynchronously to Hybrid risk engine (shadow run)
- Hybrid risk engine sends asynchronously to Cosmos DB and Blob (shadow results)
- FastAPI backend to Cosmos DB and Blob (history, reports)
Stack
- Next.js
- FastAPI
- Azure OpenAI
- Document Intelligence
- Microsoft Agent Framework
- Azure AI Content Safety
- Cosmos DB
- Blob Storage
- App Service
- Bicep
- GitHub Actions
- Azure Managed Applications
L2 · On the journeyTechnical Consultant, Software & AI · Metrodata (PT Mitra Integrasi Informatika)