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Seven AI agents run a CPA firm's night in tax season

In this case study, seven AI agents run a tax-season night at a small CPA firm in Columbus, Ohio, two days before April 15. A client's W-2 photo is unreadable at 11 PM, a 1099 from last year is missing, and 46 clients upload documents. The agents chase, sort and key the files, and write review briefs. Nothing is e-filed until the CPA reviews the return and the client signs Form 8879.

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Business
Mercer & Lane CPAs, Columbus, Ohio
Size
A CPA partner and a staff preparer
The night
Monday 11:02 PM to Tuesday 8:00 AM, two days before April 15
Agents
Seven: Otto, Intake, Docs, Prep, Brief, Money and Guard
Tools
TaxDome UltraTax CS Claude
Build time (estimate)
About three weeks, before the season
31files
complete and keyed overnight (from typed by hand the next day)
One night
6briefs
ready for the CPA at 8 AM (from notes on sticky pads)
One night
0
returns e-filed without CPA review and a signed 8879
By design
Cover of the guide: The AI CPA Tax Night Shift

Free guide · PDF · 78 pages

The AI CPA Tax Night Shift

Implementation guide for small CPA firms: the seven agents with their build specs, the IRS rules, the rollout and the templates.

View the guide Download PDF

The situation

Tax season is a flood of documents. Tax professionals e-filed 72.8 million returns by April 17, 2026, according to the IRS filing season statistics, and most of the work in a small firm is not the return itself. It is chasing, sorting and typing what clients send.

Mistakes here are expensive later. A 1099 left out of a return is a common cause of an IRS CP2000 notice, which proposes changes to income and tax.

In this case study, it is Monday, 11:02 PM, two nights before the deadline. Tanya Reed uploads her W-2. The photo is too blurry to read box two.

How the night used to go

At a small firm, uploads pile up overnight. The next morning, a preparer opens each file, finds the blurry ones, emails clients for what is missing, and types every W-2 and 1099 into the tax software.

The CPA reviews returns between calls, with notes scattered across emails. Missing forms are noticed late, sometimes after the return is filed.

The agents

Seven agents, each with one job and a written rulebook, all working inside the firm's own tools. Otto runs the night.

OttoLead

Runs the night, keeps the tally, and briefs the CPA by voice at 7:30 AM.

Never decides anything about a return.
Intake

Answers every call and text, says it is AI, and asks for a clearer photo when an upload cannot be read.

Never gives tax advice or promises a refund.
Docs

Checks each upload against last year's return in TaxDome and chases what is missing.

Never shares return data without the client's signed consent.
Prep

Keys every W-2 and 1099 into UltraTax for the preparer to check.

Never finalizes a return.
Brief

Writes the review notes: what changed, what is missing, and the questions for the CPA.

Never answers those questions itself.
Money

Tracks what each client owes and drafts extensions with a payment estimate.

Never files an extension the CPA has not confirmed.
Guard

Checks every message and action: no advice, no refund promises, no data shared without consent, no e-file without the 8879.

Never lets an action through that breaks a rule.

Step through the night

Press play, or tap any time, to follow the night from the blurry W-2 to the CPA's review.

Two nights before April 15
11:02 PM
Docs

Tanya uploads her W-2. The photo is too blurry to read box two.

1 / 8

An extension, with the money in it

Four clients are still waiting on K-1s. An extension moves the filing date, not the payment date, so Money drafts each one with a payment estimate for the CPA to confirm. Example figures for one family:

LineAmount
Estimated tax for the year$21,400
Withheld and already paid$18,200
Estimated balance due April 15$3,200
Return dueOctober 15
 Example figures. The CPA confirms the estimate.

The stack

The firm keeps its tools. The agents work inside them.

TaxDome, portal and e-sign UltraTax CS, returns Claude, the agents
  • TaxDome is the client portal: uploads, organizers, the scanner in the app and the 8879 e-signature with an identity check.
  • UltraTax CS holds the returns. Prep keys each W-2 and 1099 there for the preparer to check.
  • Last year's return is the checklist. Docs compares every upload against it to catch what is missing.
  • The phone line and texts go to Intake, which always says it is an AI.

Before and after

MomentBefore (typical)With agents
Blurry upload at 11 PMFound the next day, client emailedClear photo asked for and received by 11:20 PM
Missing 1099Noticed late, sometimes after filingCaught overnight against last year
Keying W-2s and 1099sTyped by the preparer31 files keyed for the preparer to check
Review notesScattered across emailsSix briefs ready at 8 AM
A lender asks for a returnSometimes sent in a rushHeld until the client signs consent
E-fileAfter reviewOnly after CPA review and a signed 8879
 Before: a typical firm, estimated. With agents: the night in this case study.

The value, and how we estimated it

Counted in hours and outcomes, with each assumption written out so you can redo the math with your own firm's numbers.

ValueEstimateHow we estimated it
Preparer hours back in seasonabout 10 a weekKeying, chasing and sorting for about 40 clients a week move to agents; the preparer checks instead of types.
Missing forms caught before filingmore of themEvery upload is compared to last year's return the night it arrives.
Review time for the CPAshorterEach return comes with a brief: what changed, what is missing, the open questions.
Returns e-filed without reviewnoneGuard blocks any e-file without CPA review and a signed 8879.
 Estimates, with every assumption shown.

How a build like this would run

Estimated for a firm of two to ten people on TaxDome and UltraTax, built before the season.

  1. Week 1

    Map

    Walk through last season's busiest week, the organizers, the engagement letters and the firm's AI policy. Agree on the result, for example: every upload checked the night it arrives, and a brief for every return.

  2. Weeks 2 to 3

    Build

    Intake and Docs first, then Prep and Brief. Money and Guard are built with the CPA, rule by rule.

  3. Day 30

    Prove

    Measured from TaxDome and UltraTax: files complete, forms chased, briefs ready.

  4. Every month

    Stay

    A report, rule updates when the IRS changes guidance, readiness before each season, one improvement a month.

What stays with the people

The AI chases, sorts and drafts. The CPA reviews, signs and decides.

No tax advice from the AIPractitioners cannot rely solely on AI; a person reviews (IRS OPR guidance 2026-19, Circular 230).
No data shared without consentReturn information goes to a third party only with the client's signed consent (IRC 7216).
No e-file without the 8879The signed Form 8879 must be in hand before a return is transmitted; remote signing needs an identity check.
Extensions move filing, not paymentEach extension comes with a payment estimate for the CPA to confirm.
The AI says it is AIOn every call and text, and it texts only clients who said yes.

What's in the guide

The full implementation guide behind this case study, 78 pages, free to read and to download.

  1. The business reality: how small CPA firms run tax season, their tools and where the hours go, with sources.
  2. One night at Mercer & Lane, minute by minute.
  3. The seven agents: a job card and a build spec for each.
  4. The rules: AI and Circular 230, section 7216 consent, Form 8879 and e-signature, extensions.
  5. Build and run it: the stack, the data flow, the rollout before the season and the numbers to track.
  6. Templates and appendices: the Claude skill and its files, scripts, a glossary and every source.

View the guideDownload PDF

Where the numbers come from

The tools and rules are real. The firm, the people and the amounts are invented for this case study, and the before and after are estimates.

Read the video transcript

Narrator: I built seven AI agents that run tax season at a CPA firm. Here's one night. Eleven PM, two days before the deadline, a client uploads a blurry W-2. The agents get to work while the CPA sleeps. This year, tax pros e-filed almost seventy-three million returns by deadline week. And the blueprint is free.

Narrator: Otto runs the firm's night, with six specialists: Intake, Docs, Prep, Brief, Money, and Guard. All inside the firm's own tools.

Intake (AI): Mercer and Lane CPAs, this is the firm's AI assistant. How can I help?

Tanya: Hi. I just uploaded my W-2. Did it go through?

Intake (AI): It did, but the photo is blurry, and I can't read box two. Could you retake it flat, in good light? The scanner in the app helps.

Tanya: Sure. Oh, and should I itemize this year? Would I get a bigger refund?

Intake (AI): I can't give tax advice or promise a refund. I'll put your question in front of Dan, your CPA, and he'll go over it with you.

Narrator: Intake answers every call and text, and says it's AI. Docs checks each upload against last year in TaxDome, and chases what's missing. Prep keys every W-2 and 1099 into UltraTax for the preparer to check. And Brief writes the review notes: what changed, what's missing, and the questions for the CPA.

Narrator: But nothing that commits the firm happens overnight. No tax advice, and no promises about refunds. No return data shared without the client's signed consent. And nothing is e-filed until the CPA reviews it and the client signs Form 8879.

Docs (AI): Morning, Kevin. Thirty-one files came in complete overnight, and Prep keyed them all into UltraTax.

Kevin: Thirty-one. Anything missing?

Docs (AI): The Millers. Last year they had a 1099 from Brightline Media. It's not in this year's pile, so I asked them for it.

Kevin: Good catch. That's an IRS letter waiting to happen.

Dan: Morning, Otto. How was the night?

Otto (AI): Forty-six clients uploaded documents. Tanya's W-2 was blurry, and she sent a clear one at eleven twenty. Six returns have review briefs ready for you, and four extensions are drafted.

Dan: Did anyone ask for advice?

Otto (AI): Two asked about itemizing. I said you'd answer, and put it in their briefs. And a mortgage lender asked for the Coles' return. No signed consent, so it waits.

Dan: Good. Briefs first, then the 8879s.

Narrator: At eight, the CPA reviews six returns, brief in hand. Then TaxDome sends each client the 8879, with an identity check. Only after they sign does the return go to the IRS.

Narrator: And Money tracks what every client owes. Four are still waiting on K-1s. Their extensions are drafted with a payment estimate, because an extension moves the filing date, not the payment date.

Narrator: The AI chases, sorts and drafts. The CPA reviews, signs and decides. Comment TAX, and the blueprint is yours.

For CPA firms

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