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Build library/AI Tax Return Prep Agent

Finance and data

AI Tax Return Prep Agent

8 OpenAI prompts that read messy K-1s and rental schedules, reconcile every figure, catch missed deductions, and draft tax returns to a human sign-off for firms filing at volume.

Medium setup4 steps8 prompts
Open the setup guide Discuss an implementation
Finance and data

Start with the guided setup

Follow the setup below in your own workspace. For a demonstration of the prompt-copying process, open the optional walkthrough.

Watch the setup walkthrough
Step 1 · setup
Three minutes, four steps, nothing to install by hand

Claude sets it up for you. You just paste.

Never used Claude? It is free and takes 30 seconds to open. Copy the instruction below, paste it into Claude, and it reads this page and walks you through everything, one question at a time.

  1. Tell Claude how to talk to you

    One tap. It changes how much Claude explains, and how slowly it goes. You can change it any time.

  2. Copy your setup instruction

    A short instruction plus a link to this page lands on your clipboard. First copy asks for your email once. That unlocks every button across the whole library.

  3. Open Claude in a new tab

    Free account, no card, 30 seconds. This tab stays open so you can come back.

    Open claude.ai
  4. Paste, send, and answer one question

    Claude reads this page, asks one question about your work, then guides you step by step until your first output is right. If anything looks wrong, tell Claude what you see, and it fixes it with you.

▸Prefer the full prompt instead of the link? (optional)
Click to copy
I am comfortable copy-pasting and following instructions, but I am not a developer.
There is nothing to install for this one and no commands to type: it all happens inside Claude. If any instruction below implies a Terminal, translate it into the equivalent click path for me instead.
- Plain English. Define jargon the first time it appears.
- One step at a time, then wait for me to confirm before the next one.
- Tell me what success looks like at each step, and diagnose any error before moving on.

Follow the instructions below with those rules applied.

I want to stand up OpenAI's self-improving tax agent on my own client data. Walk me through it.

This is NOT a single coding install. It is a HYBRID with two paths, and you should treat me like a tax-firm owner or finance lead who has never coded but can follow careful steps. IT help is available if I choose the API path.

**Path A, the daily filing agent, zero Terminal, runs in a ChatGPT Project or via the Responses API.**
**Path B, the self-improving loop, runs in Codex, the one place a Terminal is involved, and only weekly.**

Do Path A first (returns get drafted today). Add Path B once Path A drafts are good enough to trust at the human gate.

---

## Path A, the filing agent (no Terminal)

Pick how my data lives, then we go:

1. Go to `chatgpt.com`, sign in. Team or Enterprise is recommended so my client data stays in my org's tenant and is excluded from training; Plus works for a solo preparer testing it.

2. Left sidebar, click "GPTs" then "Projects", or the Projects entry in the sidebar. Create a Project named "Tax Agent, [client or season]".

3. Add my data the way I choose:
   - **(A) Project files:** drag the client's PDFs into the Project's files, W-2s, 1099s, K-1s, rental schedules, prior-year returns.
   - **(B) Paste:** paste raw text into the chat for a one-off.
   - **(C) Responses API:** if my IT person wants this wired into our software, the API takes the same documents as file inputs. Ask me to loop in IT and I will switch to API instructions.

4. Paste prompt 01 (the onboarding router) from the prompt vault into a new chat in the Project. Answer its four questions (return type, data source, jurisdiction and year, risk bar). It will not analyze until I answer.

5. Run prompts 02 to 06 in order on one real return. Confirm:
   - Every extracted figure shows its source document and box or line.
   - Anything handwritten or uncertain comes back low-confidence and routed to me, not auto-accepted.
   - Nothing files itself. Prompt 06 stops at a named human sign-off.

---

## Path B, the self-improving loop (Codex, weekly, light Terminal)

This is the part that makes the agent get better instead of repeating mistakes.

1. Install Codex once. If I have Node: open Terminal and run `npm i -g @openai/codex`, then `codex login` and sign in with my ChatGPT account. No API key needed if I log in with ChatGPT.

2. Make a folder (a repo) with: my prompt files, an `evals/` folder, and `corrections.jsonl`. Every time I fix one of the agent's drafts, prompt 07 logs that fix as one line in `corrections.jsonl`.

3. Once a week, from inside that folder, run Codex with prompt 08. Codex reads my corrections, finds the most common repeated mistake, writes a regression test for it, fixes the prompt or code, and re-runs the tests. It changes one root cause at a time and opens the change for my review, it does not auto-merge.

4. Over a few weeks this is what moves field accuracy up (the source build went 25% to 86% in six weeks this way).

---

## Rules

- One step at a time. Tell me which path I am on (A or B) before each instruction.
- Define jargon on first use: Project, Project files, Responses API, Codex, repo, evals, corrections.jsonl, review gate, K-1, carryforward.
- Path A never needs a Terminal. Only Path B step 1 and 3 touch Terminal, walk me through those commands with expected output and common errors (`command not found: codex` means Node or the install path, `not inside a trusted directory` means add `--skip-git-repo-check` or run `git init`).
- Anti-pattern callouts:
  - If I say "my firm blocks chatgpt.com", use ChatGPT Enterprise with SSO or the Azure OpenAI deployment under our tenant, same Project workflow.
  - If I say "I do not want any Terminal at all", I can still run Path A forever; Path B is optional, the agent just will not self-improve without it.
  - If Codex errors, NEVER tell me "it is not possible", diagnose plainly (Node missing, not logged in, not a git folder) and give the fix.
- Never tell me to file a return. A named human preparer signs off at prompt 06, every time.

First message: ask "Which return type, and where does your client data live, Project files, paste, or the API? And do you want Path B (the weekly self-improving loop) set up now or later?" Then start on the right path.

When Path A prompts 01 to 06 run cleanly on a real return AND I have logged a few corrections, switch into "loop mode" and walk me through the first weekly Codex run from the 90-day rollout playbook.
Step 2 · run it on your data

Step 1 set it up. These 8 prompts do the work.

the vault

The 8 prompts

Grab the whole pack as one file, or tap any prompt below to copy it on its own. Placeholders that look like {{THIS}} get swapped for your own numbers — and if you ran Step 1, Claude fills them in for you.

One .md file · all 8 prompts, numbered, in order · nothing left out.
Click to copy
<role>
You are the lead of a tax board: an enrolled agent, a CPA who reviews complex individual and pass-through returns, and a tax-controversy specialist. You do not file anything. You prepare drafts and surface issues for a human preparer to sign.
</role>

<task>
Before any analysis, set up this engagement. Ask me, and WAIT for my answers:

1. RETURN TYPE: (A) 1040 individual (B) 1120/1120-S corporate (C) 1065 partnership, K-1 heavy (D) 990 nonprofit (E) a mix across a client book.

2. DATA SOURCE, this decides how every later prompt receives documents:
   (A) Uploaded into this ChatGPT Project's files
   (B) Pasted as raw text into the prompt
   (C) Passed via the OpenAI Responses API as file inputs (your code calls the API)
   (D) Read by Codex from a local or synced folder of client files, one folder per client
   (E) A mix

3. JURISDICTION + YEAR: tax year, federal plus which states.

4. RISK BAR: what must be true before a draft reaches the human gate. Default: every figure traces to a source document, every assumption labeled, nothing invented.

Capture as {{RETURN_TYPE}}, {{DATA_SOURCE}}, {{JURISDICTION}}, {{YEAR}}, {{RISK_BAR}}.
</task>

<output_format>
Confirm the four answers in one short block, then say: "Engagement set. Load the client documents the way you chose, then run prompt 02." Do not analyze yet.
</output_format>

<review_gate>Stop. Wait for my four answers before proceeding.</review_gate>
Click to copy
<role>You are a tax document intake specialist on the board from prompt 01.</role>

<task>
Using the data source selected in prompt 01, inventory every document. For each, identify type (W-2, 1099-NEC/INT/DIV/B, K-1 1065, K-1 1120-S, 1098, rental schedule, prior-year return, loose note or spreadsheet), the entity it belongs to, and the tax year. Flag anything ambiguous or unreadable rather than guessing.
</task>

<output_format>Table: Document | Type | Entity | Year | Confidence | Notes. Then a list of MISSING documents expected for a {{RETURN_TYPE}} but not found.</output_format>

<constraints>Work only from the data source from prompt 01. Never invent a document. Illegible value writes "ILLEGIBLE, needs human", not a guess.</constraints>

<review_gate>Human confirms the inventory and supplies missing docs before prompt 03.</review_gate>
Click to copy
<role>You are a senior tax preparer who specializes in messy pass-through documents.</role>

<task>
Extract every tax-relevant field from the documents classified in prompt 02. Prioritize the hard ones: K-1s, rental schedules, handwritten notes, spreadsheets, prior-year carryforwards. For each field record the exact source: document name, box or line, page.
</task>

<output_format>JSON, one object per field: { "field", "value", "source_doc", "source_location", "confidence" 0-1 }</output_format>

<constraints>Use the data source from prompt 01. Every field MUST carry a source_doc and source_location. Confidence below 0.7 routes to a human, never auto-accept. No field exists without a traceable source.</constraints>

<review_gate>Preparer reviews all confidence below 0.85 fields before prompt 04.</review_gate>
Click to copy
<role>You are a Big 4 tax reviewer checking internal consistency.</role>

<task>
Values must match across documents. Reconcile K-1 income vs partnership return, 1099-B proceeds vs brokerage summary, prior-year carryforwards (NOLs, capital losses, passive activity losses) vs this year's inputs, W-2 wages vs payroll. Surface every mismatch with both sources and the delta.
</task>

<output_format>Table: Item | Source A (value, location) | Source B (value, location) | Delta | Severity (block/review/note).</output_format>

<constraints>Use the data source from prompt 01. Cite both sides of every mismatch.</constraints>

<review_gate>Human resolves all "block" severity items before prompt 05.</review_gate>
Click to copy
<role>You are a tax planner who finds every legal deduction and credit a rushed preparer would skip.</role>

<task>
Given the reconciled data, identify every deduction and credit the client likely qualifies for, including ones needing an extra document or question. Check prior-year carryforwards, QBI (199A), home office, depreciation and 179, energy credits, retirement contributions, HSA, education credits, EV credits, and state-specific items for {{JURISDICTION}}.
</task>

<output_format>Table: Deduction/Credit | Likely eligible? | Est. impact ($ or range) | Document/question needed | Authority (IRC section or form). Rank by dollar impact descending.</output_format>

<constraints>Cite the IRC section or IRS form for every item. Where eligibility needs a missing fact, list the exact question to ask the client. Never claim a credit without an authority cite.</constraints>

<review_gate>Preparer approves the deduction list and assigns client questions before prompt 06.</review_gate>
Click to copy
<role>You are assembling the draft for human review. You never file.</role>

<task>Produce a draft return summary for {{RETURN_TYPE}} {{YEAR}}: line-by-line figures with source citations, the open-issues list (anything below the risk bar), and the client-question list from prompt 05.</task>

<output_format>1. Draft figures table (line | amount | source). 2. Open issues (must clear before filing). 3. Client questions. 4. One-paragraph preparer brief.</output_format>

<constraints>Every figure cites a source. Label every assumption. Flag, never fabricate.</constraints>

<review_gate>NAMED human preparer sign-off. The draft does not leave the firm without it. Non-negotiable, maps to your professional liability.</review_gate>
Click to copy
<role>You are the agent's QA logger.</role>

<task>When the human preparer fixes something in the draft, record it as a structured failure signal: agent output, human correction, which step produced it, the source document, and the likely root cause (extraction miss, reconciliation gap, missed deduction, bad assumption).</task>

<output_format>JSON appended to corrections.jsonl: { "date", "client_ref", "step", "agent_value", "human_value", "source_doc", "root_cause", "field" }</output_format>

<constraints>Anonymize client identifiers. One line per correction. This file is the fuel for prompt 08. No correction, no improvement.</constraints>
Click to copy
You are improving a tax-prep agent. Read corrections.jsonl. Cluster the corrections by root_cause and field. For the most frequent recurring failure:

1. Write a regression eval that reproduces the failure from the cited source doc (add it to /evals with the known-correct human_value).
2. Run the existing eval suite to confirm the new test fails today.
3. Modify the relevant prompt template or extraction/reconciliation code to fix the root cause WITHOUT regressing other evals.
4. Re-run the full suite. Report which failure you targeted, the eval you added, the change you made, and the before/after pass rate.

Do not touch the human review gate. Do not auto-merge, open the change for review. Stop after one root-cause fix so each change stays bounded and testable.

Rent an army every April, or run the 7,000-return agent yourself.

This is the exact OpenAI build behind the 7,000-return, 97%-accuracy tax agent — 8 prompts you run on your own client data in your own OpenAI account. It reads messy K-1s and rental schedules, reconciles every figure, hunts skipped deductions, and a weekly Codex loop turns corrections into regression tests — the mechanic that took the source agent from 25 to 86 percent field accuracy in six weeks.

Path A · free

Run the build independently

The setup rail and every prompt above are free and stay free. The cost is your time, and the risk of wiring it wrong on live data.

Back to the prompts
Path B · done with you

Connect it to your operation

We deliver a private tax-agent workspace: the 8 prompts loaded into your OpenAI tenant, your document types and jurisdictions wired in, the Responses API connected to your software if you want it, and the Codex correction loop scaffolded with your evals folder and a weekly review cadence so the agent improves on your data — then handed over so you own it. You get Big 4 accuracy without renting an army every April.

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data safety

Before you use live numbers

  • • Run last quarter's numbers first. Live data is not a test bed.
  • • Nothing here uploads to us. It runs in your own Claude account, on your own machine.
  • • A named human reviews and signs every output before it reaches a board, lender, or client.
  • • Mask account numbers and names to the minimum the task needs.
the fine print

Straight answers on ownership

Prompt set and build authored by consultance.ai. OpenAI, Thrive, and Crete are referenced as the source proof of concept, no affiliation implied. Your client documents stay in your own OpenAI tenant; we never see them. This is not tax advice; a named human preparer signs every return before it is filed.

Read this far? You want the 7,000-return agent on your own data, not an April army. Let us build it — with a named human signing every return.

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Want this wired into your stack instead of running it yourself? That is our AI deal desk and finance automation service.

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What is AI Tax Return Prep Agent?

AI Tax Return Prep Agent is a finance and data build in the consultance.ai AI Build Library. 8 OpenAI prompts that read messy K-1s and rental schedules, reconcile every figure, catch missed deductions, and draft tax returns to a human sign-off for firms filing at volume. It fits Accounting firm owners preparing returns at volume and in-house finance teams handling their own filings who want Big 4 grade accuracy without renting an army every April. Setup difficulty is Medium, with 4 plain-English steps.

What does AI Tax Return Prep Agent do?

8 OpenAI prompts that read messy K-1s and rental schedules, reconcile every figure, catch missed deductions, and draft tax returns to a human sign-off for firms filing at volume.

Who is AI Tax Return Prep Agent for?

It fits Accounting firm owners preparing returns at volume and in-house finance teams handling their own filings who want Big 4 grade accuracy without renting an army every April.

How hard is AI Tax Return Prep Agent to set up?

Medium to set up — one guided setup instruction covering 4 plain-English steps, plus 8 ready-to-run prompts on the resource page.

How would consultance.ai build this out?

We would deliver a private tax-agent workspace: the 8 prompts loaded into your OpenAI tenant, your document types and jurisdictions wired in, the Responses API connected to your software if you want it, and the Codex correction loop scaffolded with your evals folder and a weekly review cadence so the agent improves on your data. Done with you, then handed over so you own it.

What are the licensing terms?

Prompt set and build authored by consultance.ai. OpenAI, Thrive, and Crete are referenced as the source proof of concept, no affiliation implied. Your client documents stay in your own OpenAI tenant; we never see them. This is not tax advice; a named human preparer signs every return before it is filed.

Connect this build to your workflow.

Discuss how AI Tax Return Prep Agent fits your systems, controls, and team. We define the integration, review process, and deployment requirements with you.

This build comes from our AI consulting and AI implementation practice — see the full AI in finance guide and how we work with CFO teams.

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