Billing Run → Pull Lease Terms → Compare → Flag Mismatches → Hold For Review
Lease-to-Billing Validator
Checks billing against the lease terms and flags any mismatch, wrong base rent, missed escalation, incorrect pass-through, before invoices go out, so tenant disputes and rework get caught upstream.
The Problem
Billing says one thing. The lease says another. The tenant notices.
Billing doesn't match the lease. Tenant disputes start because pass-throughs or escalations were entered wrong.
What Changes
Every charge checked against the lease before it goes out.
Compares what the lease says against what the system is billing - base rent, CAM charges, escalation timing - and flags mismatches before invoices go out.
Humans stay in control: Your team fixes any mismatch and approves billing. The agent does the line-by-line check. It removes the billing errors, not the control.
HOW THE AGENT WORKS
TRIGGERLLMAPIDECISIONACTIONWAIT
TRIGGERBilling PreparedAn invoice or billing run is staged
APIPull Lease TermsGet the abstract for each unit
LLMCompare To LeaseCheck each charge against terms
DECISIONMismatch?
ACTIONFlag For ReviewList the discrepancies
ACTIONPass CleanClear matching invoices to send
The agent doesn't change billing. It checks billing against the lease and flags mismatches. Your team corrects them before invoices send.
HOW TO BUILD IT
Three levels of depth. Pick the one that matches where you are.
For the ops person who needs to understand what's involved and brief their team.
Your BillingStaged invoices
The AgentWorkflow engine + LLM
Your LeasesTerms of record
WHAT YOUR TEAM PROVIDES ONCE
- Lease abstracts - the terms to validate against
- Billing access - the staged charges to check
- Charge rules - how rent, escalations, pass-throughs should compute
- Tolerance - what variance is acceptable vs a flag
- Review routing - who fixes a flagged mismatch
What happens day-to-day: Before a billing run goes out, the agent checks each charge against the lease, base rent, this year’s escalation, the right pass-through share. Mismatches get flagged and fixed before the tenant ever sees a wrong invoice.
For the IT person or technical lead who needs to scope the integration.
INQUIRY SOURCES
Billing / AR system
Lease abstracts
PMS
WORKFLOW ENGINE (N8N)
Trigger
API - Pull lease terms
LLM - Compare
Branch - mismatch?
Flag for review
Pass clean
Release / hold billing
CONNECTS TO
PMS / AR (Yardi / MRI / AppFolio)Read: staged billing, lease data
Lease abstract storeRead: validated lease terms
Notifications (Slack / email)Flag mismatches to lease admin
Billing approvalHold flagged, release clean
WITHOUT PMS API
Agent compares an exported billing file to abstracts and returns a discrepancy list for manual correction.
WITH PMS API
Agent reads staged billing and lease terms live and gates the run on validation. Best experience, pairs with the Lease Abstraction agent.
For the person who wants to build this agent step by step. Each node below maps to an n8n workflow node.
TRIGGERNode 1
Trigger - Billing Prepared
Fires when a billing run is staged, before invoices send.
Output: { run_id, period, charges[] }
APINode 2
HTTP Request - Pull Lease Terms
Get the lease abstract for each unit in the run.
Output: { per_unit: { base_rent, escalations[], pass_throughs[] } }
LLMNode 3
LLM - Compare To Lease
Check each charge against the lease terms and the charge rules.
Output: [{ unit, charge_type, billed, expected, match, note }]
You validate billed charges against lease terms.
For each charge, using the LEASE TERMS and CHARGE RULES, return:
- charge_type
- billed: the staged amount
- expected: what the lease implies (apply current escalation, correct pass-through share)
- match: true/false within TOLERANCE
- note: one line if mismatched
Respond ONLY with a valid JSON array.
LEASE TERMS: {lease_terms}
CHARGE RULES: {charge_rules}
TOLERANCE: {tolerance}
CHARGES: {charges}INPUT
unit 12 base rent billed 4200; lease base 4200 with 3% escalation effective this period
OUTPUT
[
{ "unit": "12", "charge_type": "base_rent", "billed": 4200, "expected": 4326, "match": false, "note": "3% escalation effective this period not applied (4200 -> 4326)." }
]DECISIONNode 4
Condition - Mismatch?
IF any charge fails outside tolerance → flag that invoice for review. ELSE → pass it clean.
Output: Branch: MISMATCH (flag) or CLEAN (pass)
ACTIONNode 5
Flag or Pass
Send flagged invoices with the specific discrepancies to lease admin; release clean ones to send.
Output: Mismatches held for correction; clean invoices cleared.
MVP vs Advanced — Where To Start
MVP — START HERE
- Exported billing file
- Abstracts from a sheet
- Core charge comparison
- Fixed tolerance
- Discrepancy list to a sheet
- Email review
ADVANCED — ADD LATER
Full Video Walkthrough Coming Soon
From a billing run to a validated invoice - step by step.
Register to be notifiedEverything on this page is free to learn.
When you're ready to build — do it yourself or bring us in.
OTHER AGENTS IN LEASING & MARKETING
Lease Abstraction Agent
Extracts key terms from lease documents into structured fields
Critical Date Guardian Agent
Watches every renewal, option, and notice deadline across the portfolio
Frequently asked questions
Lease-to-Billing Validator is an AI agent that flags mismatches between lease terms and system billing before invoices go out.
Billing says one thing. The lease says another. The Lease-to-Billing Validator addresses this — it flags mismatches between lease terms and system billing before invoices go out.
No — your team stays in control. Your team fixes any mismatch and approves billing. The agent does the line-by-line check. It removes the billing errors, not the control.
This is 3 of 3 agents in Lease Administration. → · Explore all 10 departments →