Nuntly

Transaktions-E-Mails über Nuntly senden und empfangen, eine entwicklerorientierte E-Mail-Plattform mit EU-Datenhosting. Tools für E-Mails, Domains, Webhooks, Posteingänge und Threads.

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Dokumentation

@nuntly/sdk-mcp

MCP server for Nuntly, the developer-first email platform. Exposes tools for sending emails, managing domains, webhooks, inboxes, and more.

Documentation | SDK Reference | Get your API key

Requirements
Setup
Environment variables
Programmatic usage
Tools
FAQ
Upgrading
Semantic versioning
Previous versions
Contributing
License

Requirements

Node.js 20 or later (or Bun)
A Nuntly API key from https://nuntly.com/auth/sign-up
An MCP-aware client: Claude Desktop, Claude Code, Cursor, Continue, or any custom integration based on the Model Context Protocol

Setup

Claude Desktop

Add to your Claude Desktop config:

OS	Path
macOS	`~/Library/Application Support/Claude/claude_desktop_config.json`
Windows	`%APPDATA%\Claude\claude_desktop_config.json`
Linux	`~/.config/Claude/claude_desktop_config.json`

{
  "mcpServers": {
    "nuntly": {
      "command": "npx",
      "args": ["@nuntly/sdk-mcp"],
      "env": {
        "NUNTLY_API_KEY": "your-api-key"
      }
    }
  }
}

Claude Code

Use the built-in claude mcp add command:

claude mcp add nuntly -- npx @nuntly/sdk-mcp

Then export NUNTLY_API_KEY in your shell, or paste this shape into .mcp.json manually:

{
  "mcpServers": {
    "nuntly": {
      "command": "npx",
      "args": ["@nuntly/sdk-mcp"],
      "env": {
        "NUNTLY_API_KEY": "your-api-key"
      }
    }
  }
}

Cursor

Add to your Cursor MCP settings:

{
  "mcpServers": {
    "nuntly": {
      "command": "npx",
      "args": ["@nuntly/sdk-mcp"],
      "env": {
        "NUNTLY_API_KEY": "your-api-key"
      }
    }
  }
}

Environment variables

Variable	Required	Description
`NUNTLY_API_KEY`	Yes	Your Nuntly API key
`NUNTLY_BASE_URL`	No	Custom API base URL (default: `https://api.nuntly.com`)

Programmatic usage

createMcpServer and registerTools use the McpServer type of @modelcontextprotocol/sdk v1, with zod 3, for the whole 2.x line. Moving to @modelcontextprotocol/server v2 and zod 4 is planned for 3.0. Running the stdio server (npx @nuntly/sdk-mcp) is not affected.

registerTools takes your Nuntly client: your project needs a single copy of @nuntly/sdk that satisfies this package's dependency on it: the same version for a prerelease, this version or a later 2.x for a release. Check with npm ls @nuntly/sdk or your package manager's equivalent; npm dedupe merges duplicate copies.

Embed the server

createMcpServer returns a fully-configured McpServer (all tools registered); connect it to any transport yourself.

import { createMcpServer } from '@nuntly/sdk-mcp/ai';
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';

const server = createMcpServer({ apiKey: process.env.NUNTLY_API_KEY });
await server.connect(new StdioServerTransport());

Custom integration

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { Nuntly } from '@nuntly/sdk';
import { registerTools } from '@nuntly/sdk-mcp';

const server = new McpServer({ name: 'my-server', version: '1.0.0' });
const nuntly = new Nuntly({ apiKey: process.env.NUNTLY_API_KEY });
registerTools(server, nuntly);

Tools

Tools available:

Agents: retrieve-agent-memory, upsert-agent-memory

API Keys: create-api-key, delete-api-key, list-api-keys, retrieve-api-key, update-api-key

Broadcasts: create-broadcast, delete-broadcast, list-broadcast-recipients, list-broadcasts, retrieve-broadcast, send-broadcast, update-broadcast

Contact Properties: create-contact-property, delete-contact-property, list-contact-properties, retrieve-contact-property, update-contact-property

Contacts: create-contact, delete-contact, list-contacts, retrieve-contact, update-contact

Domains: create-domain, delete-domain, list-domains, retrieve-domain, update-domain

Emails: cancel-email, list-email-events, list-emails, retrieve-email, retrieve-email-bulk, retrieve-email-content, retrieve-email-stats, send-email, send-email-bulk

Inboxes: create-inbox, delete-inbox, list-inboxes, retrieve-inbox, send-inbox-message, update-inbox

Messages: forward-message, list-message-attachments, list-messages, reply-message, retrieve-message, retrieve-message-attachment, retrieve-message-content, update-message

Namespaces: create-namespace, delete-namespace, list-namespace-inboxes, list-namespaces, retrieve-namespace, update-namespace

Organizations: list-organizations, retrieve-organization, retrieve-organization-usage

Segment memberships: add-contact-segment, list-contact-segments, list-segment-members, remove-contact-segment, retrieve-contact-segment

Segments: create-segment, delete-segment, list-segments, retrieve-segment, update-segment

Templates: create-template, create-template-version, delete-template, list-template-versions, list-templates, publish-template-version, retrieve-template, retrieve-template-version, retrieve-template-version-content, update-template

Threads: list-inbox-threads, list-thread-messages, retrieve-thread, update-thread

Topic memberships: list-contact-topics, list-topic-memberships, update-contact-topic

Topics: create-topic, delete-topic, list-topics, retrieve-topic, update-topic

Webhooks: create-webhook, delete-webhook, list-webhooks, retrieve-webhook, update-webhook

Webhooks Events: list-webhook-event-deliveries, list-webhook-events, replay-webhook-event

FAQ

Does this require Node.js or Bun? Either. The published package runs on Node.js 20+ via npx @nuntly/sdk-mcp and on Bun via bunx @nuntly/sdk-mcp. Most MCP clients spawn npx directly.

Do I need an LLM provider account? No. The MCP server only talks to the Nuntly API. The LLM client (Claude Desktop, Cursor, etc.) handles its own provider authentication.

How do I report a bug or request a tool? Open an issue at github.com/nuntly/nuntly-mcp/issues.

Upgrading

Upgrading from 1.x? See MIGRATION.md.

Semantic versioning

This package follows Semantic Versioning 2.0. The published version tracks the underlying Nuntly SDK version closely. New tools and tool argument additions are minor bumps; tool removals or argument breaking changes are major bumps.

Previous versions

Versions 1.x and 0.x remain installable from npm via npm install @nuntly/sdk-mcp@1 or npm install @nuntly/sdk-mcp@0.

Contributing

Issues, bug reports, and feature requests are welcome at github.com/nuntly/nuntly-mcp/issues.

Troubleshooting

Server does not appear in the Claude Desktop tools list Validate the JSON syntax of claude_desktop_config.json (a trailing comma silently breaks the whole file), fully quit and restart Claude Desktop, and confirm the command path resolves on your $PATH (try running it from a terminal first).

NUNTLY_API_KEY missing at startup Grab a key from nuntly.com and paste it under env in your MCP client config. The server reads the variable from the spawned process environment, not from your shell.

Tool returns isError: true The text content block holds the HTTP status, the error message, the API error code, its details when the API sent any, and the request id. Use the request id when contacting support. A 401 means the API key is missing, revoked, or scoped to a different organization.

command not found: npx Install Node.js 20 or later from nodejs.org. npx ships with Node and is the spawn target used by every MCP client in the examples above.

License

MIT. See LICENSE.