ratulsur/ap-auditor

AP Auditor — Accounts Payable Fraud Detector

Fine-tuned Phi-3.5-mini-instruct for Accounts Payable invoice auditing. Detects fraud, duplicates, pricing errors, and compliance violations instantly.

Evaluation Results

Metric	Score
JSON Parse Success	8/8 (100%)
Action Accuracy	7/8 (87.5%)
Risk Level Accuracy	7/8 (87.5%)
Flag Detection	5/6 (83.3%)
Overall	87.5%

Model Details

Property	Value
Base Model	Phi-3.5-mini-instruct
Parameters	3.8B
Method	QLoRA (4-bit NF4 + double quantization)
LoRA Rank	r=64, alpha=128
Training Samples	1,219
Real Data	CORD-v2 (400 receipts)
Synthetic Data	600 AP audit scenarios
Epochs	3
Final Train Loss	0.853
Final Val Loss	0.137

Detects

• duplicate_invoice — same invoice submitted twice
• unapproved_vendor — vendor not on approved list
• missing_po_reference — no PO number attached
• tax_discrepancy — wrong GST rate applied
• round_number_fraud — suspiciously round amounts
• split_invoice — invoices split to avoid approval threshold
• price_mismatch — amount exceeds contracted rate
• weekend_submission — invoice submitted on weekend

Usage

from transformers import AutoModelForCausalLM, AutoTokenizer, pipeline
import torch, json, re

model = AutoModelForCausalLM.from_pretrained(
    "ratulsur/ap-auditor",
    torch_dtype=torch.float16,
    device_map="auto",
)
tok = AutoTokenizer.from_pretrained("ratulsur/ap-auditor")

SYSTEM_PROMPT = """You are a senior Accounts Payable Auditor AI.
Output ONLY a valid JSON audit result."""

def audit(invoice: dict) -> dict:
    prompt = (
        f"<|system|>\n{SYSTEM_PROMPT}<|end|>\n"
        f"<|user|>\nAudit this invoice:\n\n{json.dumps(invoice, indent=2)}<|end|>\n"
        f"<|assistant|>\n"
    )
    pipe = pipeline("text-generation", model=model, tokenizer=tok,
                    return_full_text=False)
    out  = pipe(prompt, max_new_tokens=512, do_sample=False)
    raw  = out[0]["generated_text"].strip()
    match = re.search(r"\{.*\}", raw, re.DOTALL)
    return json.loads(match.group()) if match else {"error": raw}

Live Demo

Try it: huggingface.co/spaces/ratulsur/ap-auditor-demo

License

Apache 2.0