How to read a rent roll or T12 with Claude or ChatGPT
Give the assistant the report, ask for specific things (vacancy, leases ending soon, rent below the rest of the building, the biggest expense lines), and then check every total yourself against the report. A plain chat only sees what you paste, so it can miscopy a number. A connected assistant reads the report from your own records, which removes the copying step but not the need to check.
What you are asking it to read
A rent roll lists every unit with its tenant, lease dates, rent, deposit and balance owed on one date. A T12 (trailing twelve months) shows income and expenses month by month for the last twelve months, ending in net operating income. Lenders and buyers ask for both, and so should you before any decision about rent, a refinance or a purchase. The long version of how to build them is in how to keep and read a rent roll and how to prepare a T12.
An AI assistant is useful here because both reports are tables with a handful of questions every owner asks and few have time to answer by eye. It is not useful as the source of the numbers. The numbers come from your books. The assistant reads and explains them.
Three ways to get the report in front of the assistant
| Way in | What happens | Risk |
|---|---|---|
| Paste the table into the chat | The assistant works from the text you pasted. | A column can shift or a figure can be dropped on the way. Tenant names go into the chat. |
| Upload the export as a file | The assistant reads the spreadsheet or PDF. | A scanned PDF can be misread. Tenant names go into the chat. |
| Connect the assistant to your records | It calls the report itself and reads the result. | Check that the connector reads only your own portfolio and cannot change anything without your approval. |
If you paste or upload, remove what the question does not need. Unit numbers can stand in for names. See what to redact before pasting for the fields to strip.
Questions that work on a rent roll
- Which units are vacant, and what share of units is that?
- Which leases end in the next 90 days, soonest first?
- Which units pay the least rent compared with similar units (same bedrooms) in this building?
- Who owes a balance, how much, and how many months of rent is that?
- Which leases are month to month?
- What is the total monthly rent if every occupied unit pays what the roll says, and how does that compare with what was actually collected?
Ask for the arithmetic to be shown. "List the units you counted" gives you something to check in seconds. An answer that says "about 12 percent vacant" with no list is a guess.
Example a made-up six-unit building has one vacant unit and two units at $1,050 and $1,075 while the other three occupied units pay $1,250. The assistant should report one vacancy out of six units (about 17 percent), name the two lower-rent units and say the gap to $1,250 is $200 and $175 a month. If it reports anything else, ask it to list the units it used.
Questions that work on a T12
- Which expense lines are the largest, and what share of income is each?
- Which month had the biggest swing in income or expenses, and which line caused it?
- Is any line large in one month and zero in the others, which may mean a bill was booked once instead of spread?
- Do repairs and maintenance together look unusual next to the other lines?
- What is net operating income, and does it equal income minus operating expenses as written on the report?
Net operating income leaves out mortgage payments, depreciation and income tax, so the assistant should not subtract them. If it does, tell it to follow the report's own definition. The NOI guide lists what belongs above and below that line.
How to check what it tells you
- Add the unit rents yourself, or use a spreadsheet total, and compare with the figure the assistant gave.
- Ask the assistant to name the rows behind every number. Spot check three of them.
- Compare the T12's total income with what landed in your bank for the same months.
- Treat any conclusion about a cause ("the roof leak drove repairs") as a question to investigate, not a fact. The assistant has the figures, not the story.
Never let a read of a report turn into an action without you. If the assistant suggests a rent increase or a notice, it is drafting an idea. The decision and any notice are yours.
How DoorKeeping handles it
DoorKeeping connects to Claude and ChatGPT. The connector has a rent roll tool and a T12 tool that read the reports from your own books, for one property, one LLC or the whole portfolio, so nothing needs to be pasted. They only read: they cannot change a lease or post a payment. Anything involving money or a legal step waits for your one-tap approval on doorkeeping.com, and your AI app can reject an item in your approvals queue but never accept one. Rent and payments stay in your own bank accounts. DoorKeeping never holds your money and sends a payment only when you approve it. The tools are listed on the connect page.
Sources
- Model Context Protocol: Architecture overview (tools, resources, prompts), read Oct 30, 2026
- DoorKeeping: Connect Claude or ChatGPT (steps and tools list), read Oct 30, 2026
Questions
- Can ChatGPT read a rent roll PDF?
- It can read text-based PDFs and many spreadsheets you upload. A scanned image can be misread, so check totals against the original.
- Can AI calculate NOI from a T12?
- Yes, if you tell it to use the report's definition: income minus operating expenses, leaving out mortgage payments, depreciation and income tax. Check the result against the report's own NOI line.
- Is it safe to paste a rent roll into an AI chat?
- It contains tenant names and balances. Replace names with unit numbers first, or use a connection that reads the report without pasting.
- How do I know the AI did not make up a number?
- Ask it to list the rows behind each figure and check a few against the report. A figure with no rows behind it is a guess.