Programmatic Electronic Mail Dispatcher 💌

This utility establishes a Mechanized Communication Protocol (MCP) server interface grounded in the Resend Application Programming Interface (API). The primary motivation is to empower conversational AI agents, such as Cursor or Claude Desktop, to generate and transmit finalized correspondence instantly, eliminating manual copy-pasting procedures.

This capability is valuable for diverse operational workflows, such as triggering local computational tasks, soliciting input from advanced conversational models, or disseminating processed analytical results to relevant internal teams or stakeholders.

Core Technologies Employed:

• Resend (The underlying transmission service)
• Anthropic MCP Standard (The communication framework)
• Cursor (A primary integration environment)

Capabilities Overview

• Support for both unformatted text and HyperText Markup Language (HTML) message bodies.
• Functionality to mandate future delivery times for messages.
• Ability to designate Carbon Copy (CC) and Blind Carbon Copy (BCC) addressees.
• Configuration of a specific address for handling replies.
• Flexibility in defining the originating sender address (verification required).
• Utility for querying Resend audience lists.

Demonstration

Access a visual representation of its operation here: https://github.com/user-attachments/assets/8c05cbf0-1664-4b3b-afb1-663b46af3464

Initial Configuration Requirements

Presently, deployment necessitates local compilation of the project source code. Following compilation, the server must be registered within your chosen environment, be it Cursor or Claude Desktop, to enable its invocation during interactive chat sessions.

1. Secure a local clone of the repository.

bash git clone https://github.com/resend/mcp-send-email.git

1. Execute the build sequence.

bash npm install npm run build

1. Resend Credential Provisioning

Establish an account with Resend and generate an API Key. Furthermore, to dispatch mail to external domains, you must complete the process of verifying ownership of your sending domain.

[!NOTE] Consult the official Resend documentation for comprehensive guidance on sending emails using their Node.js library: Resend Documentation.

Integration Guide: Cursor

1. Access Cursor System Preferences.

Invoke the command palette (cmd+shift+p on Apple systems or ctrl+shift+p on Windows) and select "Cursor Settings".

1. Register the MCP Service Endpoint

Navigate to the "MCP" section in the sidebar and select the option to "Add new global MCP server". Inject the subsequent configuration block:

{ "mcpServers": { "resend": { "type": "command", "command": "node ABSOLUTE_PATH_TO_MCP_SEND_EMAIL_PROJECT/build/index.js --key=YOUR_RESEND_API_KEY" } } }

The absolute filesystem path to the executable script can be retrieved by right-clicking the /build/index.js file within the Cursor file explorer and choosing Copy Path.

Available Operational Parameters (Flags)

• --key: Your essential Resend authentication token (Mandatory argument).
• --sender: The verified email address designated as the message originator (Optional).
• --reply-to: The specific address designated to receive replies (Optional).

[!NOTE] Omission of the --sender argument will prompt the MCP server to request this information interactively upon every tool invocation.

1. Execution Verification

Initiate a test by interacting with the email.md file: - Update the primary recipient (to:) address to your own. - Select the entirety of the content within email.md and execute the shortcut cmd+l. - Instruct the Cursor agent (ensure it is set to "Agent" mode via the bottom-left selector) to "send this as an email".

Integration Guide: Claude Desktop

1. Access Claude's Configuration File for Developers

In the Claude Desktop application settings, navigate to the "Developer" tab and select Edit Config.

1. Register the MCP Service Endpoint

Incorporate the following configuration structure:

{ "mcpServers": { "resend": { "command": "node", "args": [ "ABSOLUTE_PATH_TO_MCP_SEND_EMAIL_PROJECT/build/index.js" ], "env": { "RESEND_API_KEY": "YOUR_RESEND_API_KEY" } } } }

Obtain the absolute filesystem path for the build script by right-clicking /build/index.js in your Integrated Development Environment (IDE) and selecting Copy Path.

Available Environmental Variables

• RESEND_API_KEY: Your required Resend authentication token (Mandatory).
• SENDER_EMAIL_ADDRESS: The source email associated with a verified domain (Optional).
• REPLY_TO_EMAIL_ADDRESS: The address designated for message replies (Optional).

[!NOTE] Failure to specify the sender email address results in the MCP server requiring this input during each tool invocation.

1. Execution Verification

Restart Claude Desktop. Confirm the resend tool is now visible and active in the Claude developer settings interface.

Engage Claude in a chat session and instruct it to utilize the resend tool for message transmission.