Your assistant gets it ready. You approve the send.
Connect Claude Code, Cursor, VS Code, or Codex to SigPen. Ask it to draft an NDA, fill in an offer letter, or find out who still hasn't signed. Nothing goes to a signer until you click Approve and send.
✓ Free Developer tier · ✓ Professional ($29/month) and up
- create_document_from_uploadDraft created
- suggest_fields6 fields placed
- update_fieldsAcme LLC, $5,000 filled in
- set_recipientsJane Doe as Client
The draft is ready. Open this link to check it and send:
Approve and send in SigPenHow it works
Connect once, then just ask.
Setup takes an API key and one command. After that you work in plain language.
Connect
Create an API key in SigPen and add SigPen to your assistant. The setup guide has the exact command for each client, and Claude Code and Cursor also have a SigPen plugin.
Ask
Tell it what you need. It drafts, places the fields, fills in the details, and sets who signs.
Approve
It hands you a SigPen link. Check the recipients and the details, then click Approve and send.
What it can do
The busywork of sending, handled in a chat.
Ask for any of these in plain language.
Check on signatures
Ask which documents are still out and who hasn't signed yet.
Draft from scratch
Describe an NDA or a simple agreement and it writes the draft, with a signature line for each party.
Use your templates
Start from one of your SigPen templates, with each signer matched to their role.
Upload your own PDF
In Claude Code or Cursor, point it at a PDF on your computer and it becomes a draft.
Place and fill fields
It places fields with AI, then fills in names, amounts, and dates you give it.
Line up the signers
It sets who signs and in which role, and can add you as a signer too.
Built to stay in your control
An assistant can prepare. It can't send.
Text inside a document can try to trick an assistant. These rules hold no matter what it reads.
- Only you can send. The assistant gets an approval link, never a send button.
- Change a recipient, a field, or the title after the link is made, and the link stops working.
- It only edits or deletes drafts it created. Documents you made in SigPen are left alone.
- Test keys can only look things up. Drafting needs a live key.
- The developer dashboard shows when an assistant last called SigPen, and with which key.
FAQ
AI assistants and SigPen, answered.
What is the SigPen MCP server?
MCP (Model Context Protocol) is the standard way AI assistants connect to outside tools. SigPen runs an MCP server, so an assistant like Claude Code or Cursor can look up your documents, draft new ones, place and fill in fields, and set who signs, all from a chat.
Which AI assistants work with SigPen?
Claude Code, Cursor, VS Code, and Codex connect with an API key in a minute or two. Any other client that supports remote MCP servers and lets you send an Authorization header works too. The Claude and ChatGPT apps need one-click sign-in, which SigPen doesn't offer yet.
Can the assistant send a document without me?
No. When you ask it to send, it gives you a SigPen approval link instead. You open it signed in, check the title, every recipient, and any values it filled in, and click Approve and send. The link lasts 24 hours, works only for you, and stops working if anything on the draft changes.
Which plans include it?
The same plans as the SigPen API: the free Developer tier, and Professional ($29/month) and up. Starter doesn't include API access.
Does it cost anything extra?
No. It's part of your plan. Drafts count toward your monthly document limit, and placing fields with AI uses one of your monthly AI detections, the same as AI Detect in the editor. Each request the assistant makes also counts toward your API key's rate limit.
What does my AI provider see?
Whatever SigPen sends back to the assistant, such as document titles and signer names and emails. Your AI provider handles that under its own terms. Document lists show signer counts, not emails.
How do I disconnect it?
Revoke the API key in the developer dashboard. That cuts the assistant off right away and cancels any approval links it created. Use a separate key named "AI assistant" so you can revoke it on its own.
Connect your assistant.
Create an API key, add SigPen to your assistant, and ask it what's still waiting on a signature.