Send Email

Send Email Skill

Overview

This skill provides the send_email tool for sending emails via SMTP or Feishu/Lark Mail. It is a standalone binary with no LLM dependencies -- pure networking only.

Usage

Call send_email with the following parameters:

• to (required, string): Recipient email address.
• subject (required, string): Email subject line.
• body (required, string): Plain text email body.
• provider (optional, string): Either "smtp" or "feishu". If omitted, the tool auto-detects based on which environment variables are present.
• html (optional, bool): When true, the body parameter is treated as HTML content. For SMTP this sends a multipart/alternative message with both plain text and HTML parts. For Feishu the body is sent as HTML directly.

Providers

SMTP

Sends email via any SMTP server (Gmail, Outlook, custom, etc.) using TLS.

Required environment variables:

Feishu / Lark

Sends email via the Feishu (or Lark) Open API using a tenant access token.

Required environment variables:

Optional environment variable:

Provider Auto-Detection

If provider is not specified in the tool call:

1. If SMTP_HOST is set, uses SMTP.
2. If LARK_APP_ID is set, uses Feishu.
3. If neither is set, the tool returns an error.

Examples

Send a plain text email via SMTP

{
  "to": "recipient@example.com",
  "subject": "Meeting Tomorrow",
  "body": "Hi, just a reminder about our meeting tomorrow at 10am."
}

Send an HTML email via Feishu

{
  "to": "recipient@example.com",
  "subject": "Weekly Report",
  "body": "<h1>Weekly Report</h1><p>All tasks completed.</p>",
  "provider": "feishu",
  "html": true
}

Explicitly select SMTP provider

{
  "to": "recipient@example.com",
  "subject": "Hello",
  "body": "Plain text content here.",
  "provider": "smtp"
}