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TAXSEMBLY / THE WORK BEHIND THE RETURN

Built by tax accountants · Evidence first

Open the work. Follow the evidence.

Every figure on a return traces back to the document it came from, the rule that used it, and the person who confirmed it. Nothing reaches a workpaper without a source you can open.

Start with Taxsembly

Watching: one W-2 becoming a workpaper

Sample 2025 W-2 on the official IRS Copy B layout. Fictional Alex Morgan, wages $48,000 and federal withholding $5,600. Marked not for filing.
EXTRACTED FIELDS2 ROWS
2025 WORKPAPERS — ALEX MORGANcontentsp. 1 of 28find in binder−   100%   +fitone pagefull pagetapecomparekeyopen PDFdownload
sign-offs: 12 / 240 · notes: 1 / 1I am:   ◉ preparer   ○ reviewer   |   ↖ browse   ○ note   △ adjust   ✓ tickmark
Tax workpapersP ✓   R ✓  

2025 Tax Workpapers

Alex Morgan · Example Accounting

DOCUMENTS2VALUES34CONFIRMED32
SIGN-OFF

Prepared by A. Lee ✓

Reviewed by Pending

CONTENTS

A   Cover and sign-off 1

B   Lead sheet 3

C   Workpapers 6

D   Source documents 12

REVIEW NOTES 1 open

PREPAREROPEN

Verify the carry-forward item before next year’s preparation.

p. 2 · Alex Lee

CURRENT YEAR   /   NEXT RETURN

+ Add a note

G   Open items26

This page

H   Review notes27

This page

I   Carry-forward28

This page
Example Accounting   ·   Alex Morgan — 2025 — page 2 of 28

CHAPTER 01 / SOURCE DOCUMENTS

Every return begins
with the evidence.

A W-2, a K-1, a brokerage packet, a client’s own spreadsheet. They arrive by upload, by portal or by email, and from that moment they belong to the engagement rather than to somebody’s inbox.

  1. Read once, on arrival.Each document is read as it lands and its pages are counted, so the cost of reading a return is a number you can see before you commit to it.
  2. A combined PDF is not one document.The scan splits a 40-page broker packet into the forms it actually contains, and each part carries its own page range back to the original.
  3. The original never leaves.Every value keeps the file, the page and the field it came from, for as long as the year exists.
THE TEST

Eleven months later, can you open the exact page a number came from without hunting for it?

TAXSEMBLY / SOURCE DOCUMENTS01
THE PRODUCT, RUNNING

Watch the documents land.

OverviewDocumentsWorkpapers A return starts empty.

Source documents

Alex Morgan · 2025 return · Example Accounting

0 files

Upload source documents — PDF, photos, Excel, CSV or ZIP; select several at once

File Status Detected form Pages
No documents yet.
Documents
0
Pages read
0
Document reading
$0.00

Illustrative document intake · fictional names and figures · the application's own layout

TAXSEMBLY / SOURCE DOCUMENTS02

CHAPTER 02 / DOCUMENT ATOMS

Break the document down.
Keep the source attached.

The scan turns a document into individual pieces of information — a label, an amount, the text around it — and each keeps the file, page and field it came from. That is what makes a number checkable rather than merely stated.

  1. Click the number, see the box.Every captured value links back to the region of the page it was read from. Review is looking, not retyping.
  2. Captured is not confirmed.A value arrives as something to review. A preparer confirms it or corrects it, and the record says which of the two happened.
  3. A correction is evidence too.When a human overrides the capture, the original reading, the new figure and the person stay on the record.
WHAT A CONFIDENCE SCORE IS NOT

It is not a decision. It never stands in for your judgment, and nothing here pretends otherwise.

TAXSEMBLY / DOCUMENT ATOMS03
THE PRODUCT, RUNNING

Click the number. See the box.

OverviewDocument reviewWorkpapers One W-2, exactly as the client sent it.
Morgan_W2_Northstar.pdf W-2 Scanning 1 page · Alex Morgan · 2025

Original document

Fit page
Sample 2025 Form W-2 for Alex Morgan — fictional figures, not for filing.

Extracted fields

0 rows
  • Reading the page…

Illustrative document review · fictional names and figures · the application's own layout

TAXSEMBLY / DOCUMENT ATOMS04

CHAPTER 03 / DETERMINISTIC AI

AI must be able
to show its work.

Hand a pile of documents to a model and accept the return it writes, and you have bought a plausible number with no way to check it. The reading is the only place a model belongs. Everything after it runs on rules you can name.

  1. Named rules, versioned.A captured field reaches a workpaper line through a rule in a schema pack, and the pack carries a version. You can say which rule produced a figure.
  2. Same inputs, same output.Run it twice and the result is identical. When it differs, an input differed, and the chain shows which one.
  3. The model still gets things wrong.Reading a scan is genuinely hard. That is exactly why the source check and the human review are not optional.
WHAT DETERMINISTIC MEANS HERE

Not “always right”. Repeatable, attributable, and explainable when it changes.

TAXSEMBLY / DETERMINISTIC AI05
THE PRODUCT, RUNNING

Run it twice. Compare.

DocumentsWorkpapersTax return One captured value, one named rule, one workpaper line.

Captured value 98%

Morgan-W2-2025.pdf

w2 · page 1 · Northstar Design Studio

Extracted source

1 Wages, tips, other comp. 48,000.00

chunk 1:p1:r1:a1

Read once. The chunk is stored.

Pack rule tax-1040 0.1.0

forms/w2.yaml

- key: wages
  label: Wages, tips, other compensation
  type: money
  required: true
  find:
    label_contains:
      - "Wages, tips, other comp"
    box: "1"

lead_sheet.yaml

group "wages" · order 1 → "Wages, tips, other comp. (Box 1)"

Version 0.1.0 · published

Workpaper line B · Lead sheet

ItemValue
Wages and withholding
Wages, tips, other comp. (Box 1) —
Federal income tax withheld (Box 2) 6,240.00

The row is matched by form and field, never by where it sat on the page.

Waiting for the run.

Run 1 · not yet run

—

pack tax-1040 0.1.0

Run 2 · not yet run

—

same stored chunks

Comparison Waiting

Two runs, then compare.

A general-purpose chatbot

Reads the page and writes a plausible number. No named rule, no version, no line reference — and the next run can answer differently.

This

One field key in one versioned pack, carrying its page and its snippet, onto one workpaper line — and a difference names its cause.

Illustrative run · fictional names and figures · the application's own layout

TAXSEMBLY / DETERMINISTIC AI06

CHAPTER 04 / THE HUMAN GATE

Your professional judgment.
At every stage.

The workpaper binder is where preparation actually happens: tickmarks against the figures you have agreed, a calculator tape beside the column you are totting, a question pinned to the page that raised it, and two separate sign-offs.

  1. Tickmarks on the page, not in your head.Mark what you agreed, where you agreed it. The next person sees the same marks on the same page.
  2. A note belongs to a page.Raise a question on the workpaper that raised it, and mark it for the next return when it carries forward.
  3. Preparer and reviewer are two records.A preparer’s tick never stands in for the reviewer’s decision. The binder counts both.
WHAT THIS DOES NOT DO

It supports your process. It does not take responsibility for the return or certify anything.

TAXSEMBLY / THE HUMAN GATE07
THE PRODUCT, RUNNING

The tools on the page.

DocumentsWorkpapersTrial balance Three W-2s, one wage lead sheet, nothing agreed yet.
I am: | sign-offs: 0 / 6 · notes: 0 / 0
Section B Lead sheet Alex Morgan · 2025
Ref Item Value Tick P R
B-1 · W-2 wages and withholding 3 rows
B-1.1 Wages, tips, other comp. W-2 · Northstar Design Studio · p. 4 $48,000.00
B-1.2 Wages, tips, other comp. W-2 · Cedar Studio LLC · p. 6 $12,450.00
B-1.3 Wages, tips, other comp. W-2 · Rivera & Co. · p. 8 $10,670.31
Wages carried to Form 1040 $71,120.31 — —

P and R beside each row are the preparer sign-off and the reviewer sign-off. Tick them in the Workpapers tab; the marks are stored on the return and printed here on the next build.

Illustrative review book · fictional names and figures · the application's own layout

TAXSEMBLY / THE HUMAN GATE08

CHAPTER 05 / TEAM PLANNING

The team. The week.
The work ahead.

Every return sits with the person who holds it. Drag one onto the day you mean to work on it and the day, the person’s load and the return all move together — no form, no second system to keep in step.

  1. Plan the day, not the deadline.Planned hours are what the team intends to do. The due date keeps its own colour so the two never get confused.
  2. Planned against logged, side by side.The timer in the return writes back here, so a 2h plan that took 5h is visible before the season ends, not after it.
  3. Day, week, month, year.The same plan at four zooms. Amber is due, red is overdue, gold is today.
WHY IT MATTERS

A season is lost in the gap between who is free and what is due. This closes it in one screen.

TAXSEMBLY / TEAM PLANNING09
THE PRODUCT, RUNNING

Watch a return get planned.

BoardPlannerReports Alex has three returns and an empty week.
‹›TodaySeptember 7–13, 2026 · Week 37 DayWeek MonthYear
MON70h
    TUE83h
    • AL 2 3h1h Rivera 2025
    WED90h
      THU100h Morgan 2025 · due
        FRI110h
          SAT120h
            SUN130h

              Illustrative planner · fictional names and figures · the application's own layout

              TAXSEMBLY / TEAM PLANNING10

              CHAPTER 06 / CLAUDE & TAX SOFTWARE

              Work with Claude.
              Keep the controls.

              Connect your firm’s Claude workspace and it can read the source-linked lead sheet, inspect a document field and prepare a handoff — always as the person who signed in, never as an anonymous robot with the keys.

              1. Every call is attributable.What was called, on which client, by whom and when. Consent is session-bound; any person can be disconnected.
              2. Answers carry their source.Ask for a figure and you get the document, page and field with it, so the answer can be checked rather than trusted.
              3. The tax software gets confirmed values only.The CCH Axcess import is authored from confirmed values against proven mappings, and every export is kept as a version.
              WHAT NEEDS SETTING UP

              Your own Claude workspace and sign-in. Coverage depends on the forms and mappings we have proven.

              TAXSEMBLY / CLAUDE & TAX SOFTWARE11
              THE PRODUCT, RUNNING

              A tool call you can audit.

              WorkpapersCCHTax return The preparer asks where a number came from.

              Claude Example Accounting workspace ALAlex Lee

              Firm settings · Claude connector

              Recent activity

              append only
              When Who What Return Outcome
              09:58 Alex Lee Signed in through Claude — OK

              Illustrative connector and import file · fictional names and figures · the application's own layout

              TAXSEMBLY / CLAUDE & TAX SOFTWARE12

              CHAPTER 07 / CLIENT DELIVERY

              Finish the work.
              Share it with confidence.

              The return goes back through the client workflow: the right version, one clear next step, and a signature that lands on the firm’s record the moment the client applies it.

              1. One shared version, not an attachment.A share names its version and its expiry. What the client opens is what your record says they opened.
              2. The 8879 signs in place.Signer, time and version are recorded on the firm side as the client signs.
              3. The evidence stays.Documents, binder and review history stay attached to the year — the only reason next year starts easy.
              ONE CONNECTED STORY

              Source → atoms → named rules → human review → team plan → tax software → client.

              Start your Taxsembly workspace
              TAXSEMBLY / CLIENT DELIVERY13
              THE PRODUCT, RUNNING

              Signed on both sides at once.

              Documents Workpapers Tax return Form 8879 The prepared return, ready to go out.

              Morgan_2025_client_copy.pdf · 38 pages

              Who receives the return

              • Alex Morgan Taxpayer alex.morgan@example.com not shared yet Re-sendCopy link
              • Jordan Morgan Spouse jordan.morgan@example.com not shared yet Re-sendCopy link

              Illustrative delivery · fictional names and figures · the application's own layout

              TAXSEMBLY / CLIENT DELIVERY14
              14 pages · 7 chapters

              Drag a page corner, use the arrows, or choose a chapter.

              Use the chapter links to explore the work.

              A source you can open. A decision you can defend.Deterministic rules and source references support review. Professional judgment stays with your team.

              Start with Taxsembly
              About the examples and integrations

              Illustrative workspace with example data; all product previews use fictional names and figures. The W-2 uses the official IRS 2025 Copy B layout with fictional details, marked not for filing. The walkthrough simplifies one wage amount; it is not a complete return. Claude connectivity requires your firm’s setup and sign-in. CCH transfer coverage depends on supported forms, mappings, and permissions. Source traceability helps investigate errors; it does not guarantee an error-free return or professional compliance.

              Explore Taxsembly

              Sample W-2 · fictional data

              Full-size sample W-2. Box 1 wages $48,000, box 2 federal withholding $5,600. Fictional details; not for filing.

              Official IRS 2025 form layout, populated for this demonstration only.