An email ends with two signatures when two things each add one: the AI writes a sign-off with your name, and then Outlook, Gmail or your automation appends your saved signature underneath. Decide which one owns the signature and switch the other off. In most setups the mail app or the workflow should own it, and the AI should be told: "Do not include a sign-off, as my Outlook signature will handle it."
That sentence comes from a Microsoft Q&A answer for people whose Copilot drafts end with "Thanks, [Name]" above their Outlook signature. The same pattern shows up wherever AI meets email. On the Zapier forum, a user sending ChatGPT replies found "most messages are ending with something like 'Best Regards, [Your Name]'" on top of their real signature, and an AI sales tool's own help tells customers to turn its sign-off off "if your email signature already includes your name."
Five reasons an email gets two signatures
1. The AI writes a sign-off and the mail app adds your signature
Copilot in Outlook and Gemini in Gmail draft inside the compose window, where your saved signature is already added. If the model also ends the body with "Best, Maya", the name appears twice. AI browser agents such as Claude in Chrome and Perplexity Comet write in the same window and hit the same problem.
Fix: tell the AI to end the body without a sign-off. In new Outlook, select the dropdown next to the Copilot icon, then "Settings", then "Draft Instructions", turn on "Use custom instructions when drafting email" and add the sentence. The Copilot guide has the exact steps and license requirements.
2. The signature is in the AI's instructions and the mail app adds it too
A common fix for unsigned AI email is to paste your signature into the assistant's custom instructions. That works for connector sends, which skip the compose window. When the same assistant then writes in Gmail or Outlook directly, the compose window adds your saved signature and the instructions add a second one. The Gemini guide covers the case where Gemini Spark works through Chrome.
Fix: keep one source per sending path. Instructions for connector sends, the mail app's settings for compose-window sends, and a check of the first email from each.
3. The workflow appends a signature and the send step adds one
Zapier's Gmail actions can add your Gmail signature through their signature field. If you also map a signature into "Body", the email carries both. n8n, Make and Power Automate add nothing on their own, so a double there means the signature is mapped twice, or the model wrote one and the workflow appended another.
Fix: use one mechanism per step. If the Zap's signature field is set, leave the body without a signature. Steps for each tool: n8n, Zapier and Make.
4. The model writes a placeholder sign-off in an automation
When an AI step writes the body of an automated email, it often ends it the way it ends a draft for a person: "Best regards, [Your Name]". The workflow then appends the real signature below the placeholder. Telling the model to stop does not always hold; the Zapier user above had "tried adding specific instructions to exclude a sign-off message".
Fix: ask for the body only, and strip whatever sign-off still appears. The answer on that Zapier thread was a Formatter step: "Text"
"Split" at the sign-off phrase, keeping the first segment. In n8n or Make, the same cut is one expression or text function before the send step.
5. Replies stack signatures from earlier messages
Every reply in a thread carries the sender's signature, and the quoted history below it carries everyone's earlier ones. That is a normal thread, and Gmail can collapse the end of a message behind three dots ("Show trimmed content"). It looks like a duplicate when an agent replying through an API puts your signature at the bottom, under the quoted history, where it reads as part of an older message.
Fix: put the signature after the reply text and above any quoted message, as a person replying in Gmail would. The Gmail API guide covers replies.
Instructions that stop the AI from signing off
Short, specific wording works best. Use whichever matches who adds the signature:
- Mail app adds it: "Do not include a sign-off, as my Outlook signature will handle it."
- Workflow adds it: "Write the email body only. End after the last sentence of the message. No closing line, no name, no contact details."
- Assistant adds it from a fetched signature: "End the body without a sign-off. Then append the signature returned by get_signature exactly once, unchanged."
Then check a real sent email, from the Sent folder, for each path. The draft preview inside an AI tool can differ from what the recipient gets.
Exactly one signature, from one source
The cleanest setup gives every sending path the same signature from the same place, and lets the model write only the message. Signatoro is built for that:
- Agentic sending. Claude, ChatGPT and other assistants connected to Signatoro's MCP server call
get_signatureand append the result once. - API fetch. n8n, Zapier, Make and your own code call
GET https://signatoro.com/api/v1/signatureand maphtmlortextafter the body. Every reply includes ausagenote that starts "Append, do not replace". - A short version.
?mode=shortreturns name, role line and one link, for cold outreach or for a reply deep in a thread where the full block feels heavy. - Update once. People install the same signature in their mail app, so emails they write and emails their agents send match.
One signature, added once
Make your signature on Signatoro. Your mail app, your agents and your automations all use the same one.
Frequently asked questions
Why does my email have two signatures?
Two things each added one. Usually the AI wrote a sign-off with your name and the mail app or automation appended your saved signature after it. Decide which one owns the signature, then tell the AI to end the body without a sign-off, or remove the second signature step from the workflow.
Why does Copilot put my name twice?
Copilot in Outlook drafts in the compose window, where Outlook already adds your signature, and it can also write its own sign-off with your name. In new Outlook, add a draft instruction such as "Do not include a sign-off, as my Outlook signature will handle it." The Copilot guide shows where.
How do I stop ChatGPT from adding a sign-off in Zapier?
Ask the model for the email body only, with no closing line or name. If a sign-off still appears, add a Formatter "Text" > "Split" step that splits the output at the sign-off phrase and keeps the first segment, then map your real signature after it.
Why is my signature at the bottom of the thread instead of under my reply?
The reply was built with the signature after the quoted history. Put the signature after your reply text and above the quoted message. Gmail users can also check the signature settings for how signatures are placed in replies.
Should the AI or the email app add my signature?
Let the email app or the workflow add it, and let the AI write only the message. A saved or fetched signature is the same every time; a signature the model writes can drift, repeat or contain details it made up.
Sources
Checked on 2026-10-07:
- Microsoft Q&A: I want to add signature to my e-mails, March 13, 2026
- Microsoft: Draft an email message with Copilot in Outlook
- Google: Troubleshoot issues with Gmail signatures
- Google: REST Resource: users.settings.sendAs (Gmail API)
- Zapier: Why isn't my signature Gmail displaying in the dropdown?
- Zapier Community: Exclude ChatGPT Sign-off Line, June 6, 2024
- Artisan: Build messaging for your campaign