ChatGPT · Tax

LawDiver Tax for ChatGPT — Setup Guide

Keep ChatGPT on verified federal tax authorities. Use the free LawDiver Tax web product today, wire a Custom GPT Action to the Tax API, or install the official ChatGPT Tax app when OpenAI lists it.

Open LawDiver TaxBack to Tax
Official Tax app — coming on the same path as caselaw. Caselaw LawDiver is already an approved ChatGPT app. Tax will follow with Install → sign in → Allow (no MCP URL to type, no key paste). Until that listing is live, use the paths below — and never paste an ld_tax_ key into a chat message.

Free web + ChatGPT side by side

You do not need ChatGPT to research tax on LawDiver. Open lawdiver.com/tax, find the Code section, ruling, or case, then paste the verified text into ChatGPT with a hard boundary:

Use only the tax authorities below. Do not cite any Code section, regulation, ruling, or case that is not in this list. If these authorities do not answer the question, say so.

[paste LawDiver Tax results here]

To check what ChatGPT already wrote, re-look up each cite on /tax or with the Tax API check endpoint, then paste the results back and tell ChatGPT to remove every cite that was not found or marked adverse.

Official ChatGPT Tax app (when listed)

When LawDiver Tax appears in the ChatGPT app directory, install it the same way as caselaw LawDiver:

  1. Create a free LawDiver account at lawdiver.com/signup if you do not already have one.
  2. On a computer, open the LawDiver Tax listing in ChatGPT and click Install (or Add / Enable).
  3. Sign in to LawDiver and click Allow. No API key paste.
  4. Start a new chat, make sure LawDiver Tax is on under Apps or Tools, and test:
    Using LawDiver Tax, retrieve IRC § 61 (current edition) and summarize gross income from the text returned.

Until that listing URL is published, prefer the web product or a Custom GPT Action below. Do not use a hand-rolled ChatGPT “custom connector” with a pasted key for Tax — that path is fragile and leaves secrets in the wrong place.

Custom GPT Action (Tax REST)

For builders: create a Custom GPT Action against https://lawdiver.com/api/v1/tax/*. This is REST, not MCP.

  1. Mint an ld_tax_ key under Account → API Keys → Tax API. Caselaw ld_live_ keys are rejected.
  2. In ChatGPT, create or edit a Custom GPT → Actions → auth type API Key, header name Authorization, value Bearer ld_tax_YOUR_KEY, Content-Type application/json, method POST.
  3. Import or paste OpenAPI for the endpoints you need from Tax API docs or LawDiver-tax-api.
  4. In the GPT instructions, require: use the LawDiver Tax action for every cite; never invent a ruling or Code section; if the action returns empty, say it was not found.
Never paste a LawDiver API key into a ChatGPT message. Put the key only in Action authentication. If you already pasted one in chat, delete that chat and rotate the key under Account → API Keys.

What LawDiver Tax can do

Same five capabilities whether you use the web, REST, MCP, or (when live) the ChatGPT app:

Search primary sources

IRC, Treas. Regs, IRS guidance, forms, pubs, IRM — not cases or treaties (those have their own tools).

Retrieve one document

Open a Code or reg section (latest held year by default), guidance, form with optional instructions, or IRM section.

Tax caselaw

Search and retrieve Tax Court / federal tax opinions with good-law and IRS context when held.

Treaties

Search or retrieve U.S. tax treaties with article text and implementing-legislation links when held.

Check IRS guidance status

Batch-check revenue rulings, procedures, and notices. “No adverse action found” means the sources checked show none — not a forever guarantee.

No invented cites

If LawDiver returns empty, the answer should say not found. Letter rulings, TAMs, and CCAs cannot be cited as precedent (IRC § 6110(k)(3)).

Messages you can copy

After the official app is on

Using LawDiver Tax, is Rev. Rul. 99-7 still good law? Use only what LawDiver Tax returns.

Side-by-side with pasted authorities

Use only the authorities below from LawDiver Tax. Do not add any cite that is not listed.

[paste results]

MCP endpoint for developers

Streamable HTTP Tax MCP: https://lawdiver.com/mcp/tax with Authorization: Bearer ld_tax_…. Catalog: toolspec.json. For Claude Tax (approved in the Claude directory), see How To Connect Claude to LawDiver Tax.

If something goes wrong

I installed caselaw LawDiver and expected Tax tools
Caselaw and Tax are separate servers. The caselaw ChatGPT app will not expose tax_search or check_tax_authority. Use /tax on the web, a Tax Custom GPT Action, or wait for the Tax app listing.
My Custom GPT Action returns 401
Use an ld_tax_ key in the Authorization header as Bearer …. Caselaw ld_live_ keys fail on /api/v1/tax/*.
ChatGPT invented a Rev. Rul.
Paste LawDiver results and say: use only the authorities below. Or look the cite up on lawdiver.com/tax and tell ChatGPT the check result.
I pasted my API key into the chat
Delete that chat. Rotate the key under Account → API Keys. Put keys only in Action auth (or wait for official OAuth).

Questions

Is there an official ChatGPT app for LawDiver Tax yet?
The caselaw LawDiver app is live in ChatGPT. The Tax vertical uses a separate MCP and REST surface (/mcp/tax and /api/v1/tax/*). An official ChatGPT Tax listing (Install → Allow, no key paste) is coming on the same pattern. Until it ships, use the free web product, a Custom GPT Action against Tax REST, or Claude Tax MCP.
Do I paste an ld_tax_ key into a ChatGPT message?
Never. A key typed into chat cannot connect to LawDiver — it only sits in your history. Use Account → API Keys only inside Custom GPT Action auth settings, or wait for the official Tax app OAuth flow.
Can I use the caselaw LawDiver ChatGPT app for IRC and Rev. Ruls?
No. That app talks to https://lawdiver.com/mcp (caselaw). Tax tools live on https://lawdiver.com/mcp/tax. Use this Tax guide and the Tax product.
Is LawDiver Tax free?
The web product at lawdiver.com/tax is free during the current rollout. API keys need a regular LawDiver account. Your ChatGPT subscription is billed by OpenAI.
Can LawDiver Tax change my files or file with the IRS?
No. It only reads: search, retrieve, and check status. It does not edit documents, send email, or file anything.

Need help?

Email support with what you tried, your ChatGPT plan, and a screenshot of any error.

[email protected]

Open LawDiver TaxClaude Tax guide
LawDiver Tax for ChatGPT — Setup Guide | LawDiver