@jihyunlab/mcp-mailer

@jihyunlab/mcp-mailer is an MCP (Model Context Protocol) server that enables Claude to send emails via any SMTP server. It supports plain text and HTML bodies, CC/BCC recipients, and can load body content from local files.

Requirements

| Variable | Required | Description | | :-------------- | :------- | :-------------------------------------------------------------- | | SMTP_HOST | Yes | SMTP server hostname (e.g. smtp.gmail.com) | | SMTP_USER | Yes | SMTP authentication username | | SMTP_PASSWORD | Yes | SMTP authentication password | | SMTP_PORT | No | SMTP port number (default: 587) | | SMTP_SECURE | No | Use TLS — set to true for port 465 (default: false) | | SMTP_FROM | No | Default sender address. Falls back to SMTP_USER when omitted. |

Registration

Claude Code (CLI)

Register mcp-mailer with Claude Code using the claude mcp add command.

claude mcp add mcp-mailer \
  -s user \
  -e SMTP_HOST=your-smtp-host \
  -e [email protected] \
  -e SMTP_PASSWORD=yourpassword \
  -- npx -y @jihyunlab/mcp-mailer

Claude Desktop App

Open the Claude desktop app settings and edit your claude_desktop_config.json to add the following entry:

{
  "mcpServers": {
    "mcp-mailer": {
      "command": "npx",
      "args": ["-y", "@jihyunlab/mcp-mailer"],
      "env": {
        "SMTP_HOST": "your-smtp-host",
        "SMTP_USER": "[email protected]",
        "SMTP_PASSWORD": "yourpassword"
      }
    }
  }
}

After saving, restart the Claude desktop app.

Usage

Once registered, ask Claude to send an email in natural language.

Send a plain text email

Send an email to [email protected] with the subject "Hello" and body "Hi Alice, how are you?"

Send an HTML email

Send an HTML email to [email protected] with the subject "Newsletter" and the HTML body "<h1>Hello!</h1><p>Welcome to our newsletter.</p>"

Send with CC and BCC

Send an email to [email protected], CC [email protected], BCC [email protected], subject "Meeting", body "Please find the agenda attached."

Send using a local file as the body

Send an email to [email protected] with the subject "Report" and use the file at /Users/me/report.txt as the body.

Tool Reference

send_mail

Sends an email via the configured SMTP server.

| Parameter | Required | Type | Description | | :------------- | :------- | :----- | :--------------------------------------------------------------------- | | to | Yes | string | Recipient address. Use comma-separated values for multiple recipients. | | subject | Yes | string | Subject line of the email. | | from | No | string | Sender address. Falls back to SMTP_FROM, then SMTP_USER. | | cc | No | string | CC recipients. Use comma-separated values for multiple recipients. | | bcc | No | string | BCC recipients. Use comma-separated values for multiple recipients. | | text | No | string | Plain text body. | | textFilePath | No | string | Absolute path to a local .txt file to use as the plain text body. | | html | No | string | HTML body. Takes priority over plain text when both are supplied. | | htmlFilePath | No | string | Absolute path to a local .html file to use as the HTML body. | | attachments | No | array | Array of attachment objects. |

At least one of text, textFilePath, html, or htmlFilePath must be provided.

Attachment Object

| Field | Type | Description | | :------------ | :----- | :--------------------------------------------------------------------------- | | filename | string | Name of the attached file. | | path | string | Absolute path to the file to attach. | | content | string | Plain text or base64 string content for the attachment. | | contentType | string | Optional MIME type for the attachment (e.g. application/pdf). | | cid | string | Optional Content-ID for embedding images in HTML bodies (e.g. logo). | | encoding | string | Optional encoding for the content (e.g. base64). |

Send with attachments

Send an email to [email protected] with the subject "Files" and body "Here are the files." and attach /Users/me/document.pdf and /Users/me/image.png.

Credits

Authored and maintained by JihyunLab <[email protected]>

License

Open source licensed as MIT.