@nuntly/sdk-mcp) gives Gemini CLI tools to send email, manage domains and webhooks, and read and reply to inbound messages. Check the prerequisites first: an API key and Node.js 20 or later.
Create an API key
In the dashboard, go to API Keys and create a key with the Sending only permission, and leave Restrict to domains empty. Copy it. Pick Full access instead for an agent that manages domains, inboxes, webhooks or agent memory. See API keys.Add the MCP server
Run this in a terminal. Paste your key when the cursor waits, and press Enter:bash or zsh
-s user stores the server in ~/.gemini/settings.json, outside your repository. Without it, gemini mcp add writes to the project’s .gemini/settings.json, which you may commit with the key in it.
Gemini CLI connects a local MCP server only in a folder you trust. Start gemini in your project and trust the folder when it asks, then check the connection:
nuntly line reads Connected. In a Gemini CLI session, /mcp lists the tools the server exposes.
Share the server with your team
Commit a.gemini/settings.json file at the project root. It reads the key from the environment Gemini CLI starts in, so each person sets their own NUNTLY_API_KEY:
.gemini/settings.json
env block: Gemini CLI removes every variable whose name contains KEY from the environment it passes to an MCP server, unless the server’s env names it.
Send a test email
Ask your agent: “Send a test email from hello@onboarding.nuntly.com to my address.” Use the email address of your Nuntly account (the organization owner), exactly as you signed up. This sender only delivers to that address.Troubleshooting
gemini mcp list shows nuntly as Disabled. The current folder is not trusted, so Gemini CLI does not start local MCP servers there. Start gemini in the folder and trust it.
gemini mcp list shows nuntly as Disconnected. The server started without a key. With the project file, NUNTLY_API_KEY is unset in your shell, or the env block is missing and Gemini CLI removed the variable. Run npx -y @nuntly/sdk-mcp@2 in a terminal to see the server’s own error.
For errors shared by every client, such as a tool that returns isError: true, see Troubleshooting.
Next steps
AI agent inboxes
Give the agent its own inbox and a memory per thread
What an agent can do
See which operations stay with you