Connect Claude or ChatGPT to Signatoro with MCP
Add the MCP server of Signatoro, the agentic email signature platform, to Claude, Claude Code or ChatGPT: make a free email signature in chat, fetch or edit your saved one, sign as one of your AI assistants, and manage your company's people.
-
Signatoro runs a hosted MCP server. Add it to Claude, Claude Code, ChatGPT, Grok or any other MCP client, and the assistant can make an email signature, give the steps to install it in a mail app, fetch and edit the signature you saved, send with an AI assistant's own signature, and, for a company owner, add, update and remove the company's people.
The server address is:
https://signatoro.com/mcp
It speaks MCP over streamable HTTP. Making a signature and reading the install steps work right away. The tools that use your Signatoro account ask you to sign in the first time you call one.
Three tools work without an account, eight with one
Without signing in:
| Tool | What it does |
|---|---|
create_signature | Makes a free signature from a name plus an optional title, company, phone, email, website, LinkedIn, layout and color. Returns HTML, plain text and claimUrl, a link that opens the free generator with the same details and layout, to save it to an account and keep editing. Nothing is saved until you do. The link works for 7 days. |
list_templates | Lists the layouts, each with what it shows and when it fits. |
get_install_steps | Returns the steps from Signatoro's install guide for a mail app, such as gmail, outlook-new or apple-mail, with the link to the full guide. |
Signed in:
| Tool | Who | What it does |
|---|---|---|
get_signature | Everyone | The assistant calls it for an email you want signed, with any mail tool, and appends your saved signature; with the email signature rule in its instructions, it calls it before every email it sends or drafts. Returns it as HTML and text, with sender: your name, title, company, email, phone, website, LinkedIn and booking link as fields, so the body uses your real details. Pass signature with an agent's id or name to send with that agent's signature instead. Each call counts as one API request: 50 a month on Free, unlimited on a company plan. |
list_signatures | Everyone | Lists the signatures you can send with: your own (me, the default) and those of your AI assistants and of company agents you can use, each with how it signs, its disclosure line choice and a one-line preview. |
update_my_signature | Everyone | Changes the fields you name in your saved signature, or creates it if you have none yet. Returns the updated signature with sender, which counts as one API request like get_signature. A connected mailbox gets the new version. |
list_members | Company owners | Lists the company's people with their status and whether their signature is installed. |
add_member | Company owners | Invites a person by email with their name, title and phone. They get the invitation with their signature in it. |
update_member_field | Company owners | Changes a person's name, title or phone. A joined member gets their updated signature by email. |
remove_member | Company owners | Removes a person from the company. This cannot be undone, so it takes two steps: the assistant shows you who would be removed, and removes them only after you say yes. |
resend_invite | Company owners | Sends an invitation again and renews it if it expired. |
Each company tool follows the rules of the company page: only an owner can use it, the plan's size limit applies, and the primary owner and the person asking always stay in the company.
In a company, the company sets the company name, website, logo, layout, color, font, review badge and footnote for everyone, and the booking button when it sets one (otherwise each person keeps their own). get_signature and update_my_signature list those parts and who changes them: an owner gets the link to the company's page on signatoro.com, and a member is told to ask the owner. update_my_signature leaves those fields as they are and says which ones it skipped.
Choose which signature to send with
An AI assistant can send with your signature or with one of your AI agents' own, which carry a line saying it is an AI and whom it acts for. Set the agents up on Signatoro first: the agent guide covers the two ways an agent signs and the disclosure line choices.
- Pick per email. Under "Connected assistants" on your Connect page, leave "Signs as" on "Me". The assistant calls
list_signatures, passes the one it wants toget_signatureassignature, and asks you when it is unclear which one an email needs. - Lock the connection to one agent. Set "Signs as" to the agent. Every
get_signaturecall then returns that agent's signature, andlist_signatureslists only that agent.update_my_signatureis refused on that connection, since the agent's signature is managed on signatoro.com.
An agent's signature comes back with two more fields, as in the agent guide: agent, with its name, whom it acts for and disclosure (the line in the signature and a label sentence for the first line of the body, the agent's call), and signature, naming the one that was served. Keep the disclosure line; it is part of the signature. When a company requires one line for every agent, companyControlled lists "AI disclosure".
If the agent was deleted, or is no longer yours, get_signature returns an error and serves nothing, your own signature included. Bind the connection to another agent, or set it back to "Me", on signatoro.com.
Connect Claude
Signatoro is in Claude's connector directory: Signatoro in Claude. The same listing serves Claude.ai, the desktop and mobile apps, Claude Code and Cowork.
- In Claude, open Customize, then Connectors.
- Find Signatoro in the directory and connect it.
- In a chat, click "+" at the lower left, then Connectors, and turn Signatoro on.
On a Team or Enterprise plan, an owner adds Signatoro under Organization settings, then Connectors, and each member then connects with their own Signatoro account. A Team member without that permission clicks "Request", which asks the owners to add it.
When a tool needs your account, Claude shows a Connect card in the chat. Sign in to Signatoro, check what the assistant asks to do, and click "Approve".
In Claude Code, run this in a terminal:
claude mcp add --transport http signatoro https://signatoro.com/mcp
Claude Code opens the Signatoro sign-in page in your browser the first time a tool needs your account.
Connect ChatGPT
Signatoro is in ChatGPT's plugin directory: open "Plugins" in ChatGPT's sidebar, find Signatoro, or open the Signatoro plugin, and click "Install plugin". ChatGPT asks you to sign in to Signatoro the first time a tool needs your account.
To add the server yourself instead, ChatGPT connects to your own MCP servers in developer mode, on ChatGPT on the web. OpenAI documents the switch in two places and the labels differ by account, so if one path is missing, try the other:
- Turn on developer mode: Settings, then "Security and login", then "Developer mode". Some accounts have it under Settings, then Apps, then "Advanced settings".
- Add the server: on ChatGPT's Plugins page click the plus button, or under Settings, then Apps, click "Create". Give it the name Signatoro, paste
https://signatoro.com/mcpas the server URL, keep OAuth as the authentication, and create it. - Start a new chat and add Signatoro from the tools menu.
On a Business, Enterprise or Edu workspace, an admin turns on developer mode for the workspace first.
Connect Grok
xAI documents custom connectors for Grok:
- Go to grok.com/connectors.
- Click "New Connector", then "Custom".
- Enter
https://signatoro.com/mcpas the MCP server URL and sign in to Signatoro.
On Grok Business and Enterprise, a team admin provisions the connector first. A Grok Bot fetches the signature from the API instead: the Grok Bot guide has the steps, and the Grok guide covers every other way Grok sends email.
Sign every email
Connected, an assistant adds your signature to an email you ask it to sign. To have it sign every email it sends, or ask you each time, add the email signature rule to its instructions: "Instructions for Claude" in Claude's Settings, ChatGPT's custom instructions, a Grok Bot's instructions, or CLAUDE.md or AGENTS.md for a coding agent.
Connect with an API key
Some agents add an MCP server with a URL and a header, and have no OAuth sign-in. Connect them with a Signatoro API key:
- On the Connect page, under "For tools and assistants", click "Generate API key". For an AI agent, generate the key for that agent, so it always gets the agent's signature.
- In the agent's MCP settings, enter
https://signatoro.com/mcpas the URL and the key as the bearer token: the headerAuthorization: Bearer sig_live_....
A key reads signatures: get_signature, counted like the REST API, and list_signatures, which is not counted. Changing your signature and managing your company's people take the OAuth sign-in. To end the connection, revoke the key on the Connect page.
Find Signatoro in MCP directories
- Claude's connector directory: connect Signatoro in Claude.ai, the Claude apps, Claude Code and Cowork.
- Smithery: add Signatoro to your toolbox and connect it from any client Smithery supports.
- The official MCP Registry, as
com.signatoro/signatoro: clients that read the registry find the server by that name.
A prompt to start with
Use Signatoro. Make me an email signature: Maya Okafor, Head of Operations at Northwind Supply, +44 20 7946 0123, northwind.co. Show me the layouts first and use the one that suits a reply-heavy inbox. Then give me the steps to add it in Gmail.
Signed in:
Use Signatoro. Change the title in my signature to Head of Design and send me the updated version.
For an owner:
Use Signatoro. List the people in my company, then invite sam@northwind.co as Sales Lead.
Signing in and privacy
Signing in uses OAuth. The assistant sends you to Signatoro's own sign-in page, where you sign in as usual, with two-factor authentication if you set it up, and approve the connection. The assistant receives a token that works only with https://signatoro.com/mcp, lasts an hour and renews itself. Your password stays with Signatoro.
The server handles signature details and your company's people. The email you write stays between you, the assistant and your mail app. To end a connection, remove the connector in Claude or ChatGPT.
Signatoro MCP questions
What is the Signatoro MCP server URL?
The Signatoro MCP server URL is https://signatoro.com/mcp. It uses the streamable HTTP transport. Add it as a custom connector in Claude, as an app in ChatGPT developer mode, or with claude mcp add --transport http signatoro https://signatoro.com/mcp in Claude Code.
Do I need a Signatoro account to use it?
Making a signature with create_signature, listing layouts and getting install steps work without an account. Fetching your saved signature with get_signature, editing it with update_my_signature and managing a company's people need a Signatoro account, and the assistant asks you to sign in the first time.
How many times can an assistant fetch my signature?
Each get_signature call counts as one API request, the same count as the signature API. The Free plan includes 50 requests a month, and a company plan has no limit. An update_my_signature call that changes something counts as one request too, since it returns the updated signature. With the month used up, the change is still saved.
Why can't the assistant change my logo or review badge?
In a company, the logo, colors, layout, font, website and review badge come from the company, and the booking button too when the company sets one, so every signature matches. The company's owner changes them on the company's page at signatoro.com. The assistant tells you which parts these are and who to ask.
Can an AI assistant sign emails as itself instead of as me?
Yes. Add an AI assistant on your Connect page, choose whether it signs as you or as itself, and pick its disclosure line. Then the assistant passes it to get_signature as signature, or you lock the connection to it under "Connected assistants". Assistants come on top of the people your plan covers.
Can an assistant manage my company's people?
Yes, when you own the company. After you approve the connection, the assistant can list, invite, update and remove people and resend invitations, with the same limits as the company page. These tools are for owners only.
Related: Gmail MCP and Outlook MCP, for adding your signature to email sent through Google's and Microsoft's mail MCP servers.
Sources
Checked against the vendors' own documentation on 2026-09-28:
- Get started with custom connectors using remote MCP (Claude Help Center, updated 2026-08-11)
- Authentication for connectors (Claude Docs)
- Lazy authentication for MCP servers (Claude Docs)
- Connect Claude Code to tools via MCP (Claude Code Docs)
- Connect and test your plugin (OpenAI Developers)
- Developer mode and MCP apps in ChatGPT (OpenAI Help Center)
- Connectors (xAI Docs, read 2026-10-08)
- MCP authorization, 2025-11-25 (Model Context Protocol)
Was this page helpful?
Connect my agent
Add Signatoro to your agent as an MCP server:
https://signatoro.com/mcpThen ask it to make your email signature. It gives you a link to save it to Signatoro.