Attach your PDF like you always do
On ChatGPT, Gemini, or Claude, attach a PDF the way you normally would. The add-on quietly intercepts the upload before it leaves your browser.
You'll need to give 60 days' written notice and pay a fee equal to two months' rent — on top of any rent you still owe. Most leases ask for 30 days' notice without a separate fee. If you think you might move within the term, this is the clause to negotiate first.
Free. Donate only if it helped.
How it works
Attach a PDF the way you always do. The add-on redacts it in your browser, you review, and the AI only ever sees the redacted version.
On ChatGPT, Gemini, or Claude, attach a PDF the way you normally would. The add-on quietly intercepts the upload before it leaves your browser.
Names, addresses, account numbers, government IDs, company names — found locally with pattern matching and an on-device name detector. Nothing is uploaded to do this.
You see exactly what will be removed and can adjust it. The add-on swaps your file for redacted-document.md, so the AI only ever sees the redacted text — along with ready-made prompts to explain the document in plain language.
Why local-first
Most AI tools ask you to trust them. We'd rather show you the pipeline that runs in your browser.
PDF parsing, pattern matching, and the name detector all run locally on your device. The model is bundled with the add-on and never calls out.
Your original PDF is held back the moment it's detected, and only re-attached if you explicitly choose "Use original." The AI sees redacted-document.md — not your file — and the original stays blocked until proof shows the redacted file is present and the original absent.
You review every detection and can toggle items off or add your own before anything is shared. No black boxes.
No login, no payment, no email. It's free — and if it helped, you can leave an optional donation. Nothing else.
This Lease Agreement (the "Agreement") is made and entered into as of October 14, 2026, by and between Margaret A. Chen ("Landlord"), with mailing address at 412 Hawthorne Lane, and Jordan Patel ("Tenant").
Tenant's government ID on file: •••• ••• 134. Tenant shall pay rent via direct deposit to account ••••3982 on or before the first day of each month…
Use it for
Notice periods, automatic renewals, deposit terms, who fixes what.
Non-competes, IP assignment, equity vesting, separation clauses.
Term length, scope of confidentiality, mutual vs one-way obligations.
Arbitration clauses, data rights, what changes if they update the terms.
Coverage limits, exclusions, what counts as "pre-existing."
If it has a signature line, you should know what's above it.
Questions, answered
Yes. Reading the PDF, finding sensitive information, and the name detector all run locally in your browser. Only the redacted Markdown — with names, addresses, account numbers, and government IDs already removed — is attached to your AI chat.
No. There's no login, no account, and no payment. Install the add-on and start using it right away.
No. DocsUnderstood helps you understand what a document says — it doesn't replace a lawyer. For high-stakes situations, take what you've learned here and bring it to one. You'll have better questions to ask.
Text-based PDFs. Scanned or image-only PDFs and password-protected PDFs are out of scope for now. It works when you attach a PDF on ChatGPT, Gemini, or Claude.
It's free. There's no charge and no subscription. If it helped, you can leave an optional, pay-what-you-want donation — only if you want to.
ChatGPT (chatgpt.com and chat.openai.com), Gemini (gemini.google.com), and Claude (claude.ai). When you attach a PDF on any of these, the add-on steps in before it leaves your browser.
Chrome and Edge at launch. Firefox isn't available yet.
The interface and the ready-made "understand this document" prompts are available in English, Korean, Chinese, Spanish, Hindi, and French.
It's free. Install it once and it protects your PDFs in the browsers you already use. Donate only if it helped.
Free to use. If it helped, you can support the project.