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How to connect Otto to AI assistants with MCP

Let Claude, ChatGPT or another AI assistant look up websites, find and keep businesses, run campaigns and read replies in your cold email, with an API key. Nothing is sent without your yes in Reviews.

Updated 2026-10-31

MCP (Model Context Protocol) is how AI assistants such as Claude and ChatGPT use other services. Otto has an MCP address for your cold email, so you can ask your assistant things like "look up who runs acmeplumbing.com" or "which replies this week were interested?" and it works with your real Otto data.

Every route, with what it takes and gives back, is in the API reference.

What you need

  • Cold email switched on for your business.
  • An API key. Make one under Settings → Integrations → API keys and tick what the assistant may do: Leads and lookups, Cold campaigns, Cold email replies, or several. See how to read your data with an API key.
  • The MCP address, shown under AI assistants (MCP) in the same place. Press Copy address. It is your Otto site followed by /hooks/mcp.

Connect your assistant

Add Otto to your assistant as a remote MCP server (it may be called a connector or a custom tool) using the address, and add the header Authorization with the value Bearer followed by your key.

In Claude Code, run:

claude mcp add --transport http otto https://your-otto-site/hooks/mcp --header "Authorization: Bearer otto_..."

Any MCP client that lets you add a header works the same way. An app that only offers to sign in, with no place to add a header, cannot use an API key yet.

What the assistant can do

The assistant sees only the tools your key's ticks allow:

  • Leads and lookups: look up the decision-maker at a website, look up many websites at once, read your credits, turn a sentence into search filters, find businesses for a draft campaign, list what was found, and keep or pass on what was found.
  • Cold campaigns: list and read campaigns with their figures, make a campaign, change a draft, add your own list as CSV, have Otto write the emails, ask to start a campaign, and pause, resume or cancel one.
  • Cold email replies: list the sorted replies with Otto's drafted answers, and answer one.

What costs credits

  • One credit is one email delivered by a campaign you approved. A bounce gives it back.
  • Lookups, finding businesses and keeping them are free.
  • Turning a sentence into filters and having Otto write the emails cost no credits.

The assistant cannot start sending by itself: a campaign it starts waits in Reviews for your yes. Tick only what you want it to use.

What it can never do

The assistant cannot approve anything. Asking to start a campaign puts it in Reviews, and nothing is sent until you approve it there. An answer to a reply waits in Reviews too, unless you set answering cold email replies to Auto. It can never see or change your settings, your keys or your money.

Words from replies and from businesses' websites are passed to the assistant marked as content to read, never as instructions to follow.

Limits and the log

The assistant shares the key's limit of 60 requests a minute with anything else using that key. Every request it makes is listed under Recent uses beside the key, with the tool it used. To stop it at once, press Revoke on the key.