SignMaster in ChatGPT
ChatGPT can work with your SignMaster account through SignMaster's MCP server, added to ChatGPT as a custom app. Ask it what's still unsigned, have it draft an envelope from a template or line up reminders, then approve anything that emails people from inside SignMaster.
Updated November 5, 2026 · 2 min read
Connect ChatGPT
- 1
Copy the address
In SignMaster, open Settings › Connect an AI and copy the connector address from the ChatGPT card.
- 2
Add a custom MCP server
In ChatGPT, add a custom MCP server: name it SignMaster, paste the address as the server URL and choose OAuth sign-in. OpenAI has moved this option over time, from developer mode under Settings › Apps › Advanced settings to the Plugins page's Add custom MCP server, so use whichever your account shows.
- 3
Allow access
When ChatGPT starts the sign-in, a SignMaster page opens. Sign in, review what ChatGPT may do and press Allow access.
- 4
Use it in a chat
Start a new chat and pick SignMaster, for example by typing @ and choosing it, then ask your question.
Check your ChatGPT plan
OpenAI decides who can add custom MCP servers, and it has changed this more than once. Business, Enterprise and Edu workspaces have it, often only once an admin allows it; on personal plans, custom servers may be limited or read-only. If you can't find the option, check OpenAI's current help pages or ask your workspace admin.
What you can ask
- Which contracts went out this week and are still unsigned?
- Show me the fields on my Window replacement template.
- Draft an envelope from the Lawn care agreement for Sam Patel, sam@example.com.
- Find Morgan Lee in my contacts and tell me what we've sent them.
- Void the duplicate Maple Avenue contract; the customer signed the other one.
- Write a one-page photo release and save it in SignMaster as a template.
Approvals
Lookups and drafts happen right away. Sending, reminding and voiding wait: SignMaster stores each request with its exact recipients and asks you to approve it in Settings › Connect an AI. Deny it and ChatGPT is told no. If nobody answers, the request expires on its own.
Permissions and control
ChatGPT acts as you, not as an admin. It gets your role's access, narrowed to the permissions you left ticked when you allowed it, and SignMaster re-checks them on every request. A contract ChatGPT drafts stays a draft until a person sends it, so read the wording first: an AI wrote it.
To cut it off, choose Disconnect next to ChatGPT in Settings › Connect an AI. It stops working right away. Delete the server in ChatGPT as well, so it no longer appears in your chats.
Questions? Answers.
Is SignMaster in ChatGPT's app directory?
No. You add it yourself as a custom MCP server with the address from Settings › Connect an AI, which is why ChatGPT may show a warning about custom servers first.
Does it cost anything?
Connect an AI is on every SignMaster plan at no extra cost. Your ChatGPT plan has to allow custom MCP servers.
Can ChatGPT change a signed contract?
No. It can look up envelopes and get you a link to a signed copy, within your permissions, but completed documents can't be edited by anyone.
What about Gemini or Copilot?
Both work. Gemini CLI and Gemini Enterprise, Copilot Studio and GitHub Copilot in VS Code connect with the same SignMaster address. Settings › Connect an AI has the steps for each, and Claude works too: see SignMaster in Claude.