simple-email-mcp

A provider-agnostic MCP server for email (IMAP/SMTP). Works with any email provider — Purelymail, Gmail, Outlook, DomainFactory, or any standard IMAP/SMTP server.

Built for Claude Desktop, Claude Code, and any MCP-compatible client.

Features

• Multi-account — manage multiple email accounts from different providers
• Read, search, list — full IMAP support with folder browsing
• Send emails — plain text, HTML, or both (multipart/alternative)
• Attachments — send via file path or base64-encoded inline data
• Download attachments — extract attachments from received emails as base64
• Calendar invites — send proper ICS invitations with Accept/Decline buttons
• Save to Sent — automatically saves sent emails to the Sent folder via IMAP
• Optional send gate — configurable confirmation code to prevent accidental sends
• International folders — handles UTF-7 encoded folder names (German, etc.)
• Compact MCP surface — one email tool with lazy action discovery to reduce client context use

Tools

Version 2 exposes a single MCP tool named email. Call it with only an action to discover that action's parameters, then call it again with params.

{"action": "send"}

{
  "action": "send",
  "params": {
    "account": "work",
    "to": "recipient@example.com",
    "subject": "Hello",
    "body": "Message body"
  }
}

list_accounts returns the exact account names plus any configured send_as, display_name, and description, so clients can use the explicit account token instead of guessing partial matches.

Configuration validation

Use validate_config after editing accounts.json or environment variables. It checks required fields, email-like addresses, ports, SMTP security, providers, and placeholder hosts without exposing passwords or logging into IMAP/SMTP.

{
  "action": "validate_config",
  "params": {}
}

Migrating from v1

Most users do not need to change their MCP client configuration. Keep the same simple-email-mcp command and restart the client after upgrading.

The breaking change only affects clients or scripts that call exact v1 tool names such as email_send_email or email_read_email. In v2, use the single email tool with an action instead:

Sending with attachments

Preflight metadata only (recommended before send):

attachments: "/path/to/file.pdf, /path/to/doc.xlsx"

Call prepare_attachments first to verify resolved paths, file names, sizes, MIME types, and missing files without loading contents into context.

File path (when the MCP server has filesystem access):

attachments: "/path/to/file.pdf, /path/to/doc.xlsx"

Base64 inline (when the caller is in a sandbox):

attachments_inline: [{"filename": "report.pdf", "content_base64": "JVBERi0...", "content_type": "application/pdf"}]

Sending calendar invites

Pass raw ICS content via calendar_ics. The email is structured as multipart/alternative so clients display Accept/Decline buttons:

calendar_ics: "BEGIN:VCALENDAR\r\nVERSION:2.0\r\n..."

Send confirmation gate

If send_code is set in accounts.json, the AI must show the email draft to the user and wait for them to provide the code before sending. This is useful as a workflow checkpoint to reduce accidental sends.

Important: this is not a hard security boundary if the MCP process and the AI runtime can both read the same config source. In that setup, the AI may be able to read the code from accounts.json or environment variables. Remove or clear send_code to disable the checkpoint.

Testing

Run the regression suite from the repo root:

.venv/bin/python -m unittest discover -s tests -v

Security

• Passwords are stored in accounts.json — add it to .gitignore
• The send_code gate is a user-intent checkpoint, not a hard secret, unless the AI cannot read the config source that contains it
• No passwords are exposed via the list_accounts action
• File attachments: The attachments parameter reads files from paths the AI provides. If the MCP server runs with broad filesystem access, the AI could theoretically attach and send any readable file. Use attachments_inline (base64) in sandboxed environments, or restrict filesystem access at the OS/container level.
• Saving attachments: save_attachment fails if the target file already exists unless overwrite=true is set explicitly.

Provider Notes

Gmail

Use an App Password (not your Google password). Enable IMAP in Gmail settings.

Outlook / Microsoft 365

Use an App Password or enable basic auth for IMAP/SMTP.

Purelymail

Use your Purelymail account password directly.

License

MIT — see LICENSE

Authors

• Ramon Ramirez (@mexican75)

Quick Start

1. Install

pip install simple-email-mcp

Or from source:

git clone https://github.com/mexican75/simple-email-mcp.git
cd simple-email-mcp
pip install .

2. Create accounts.json

{
  "accounts": [
    {
      "name": "personal",
      "address": "me@example.com",
      "password": "your-app-password",
      "provider": "gmail"
    }
  ]
}

3. Add to your client

Claude Code (global, all projects):

claude mcp add email -s user -e ACCOUNTS_FILE=/path/to/accounts.json -- simple-email-mcp

Claude Desktop — add to config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "email": {
      "command": "simple-email-mcp"
    }
  }
}

Or if running from source:

{
  "mcpServers": {
    "email": {
      "command": "python",
      "args": ["/path/to/simple_email_mcp.py"]
    }
  }
}

4. Restart your client

Configuration

accounts.json

{
  "send_code": "MYSECRETCODE",
  "accounts": [
    {
      "name": "work",
      "address": "me@company.com",
      "send_as": "alias@company.com",
      "display_name": "Jane Doe",
      "description": "Primary work mailbox",
      "password": "app-password",
      "provider": "outlook"
    },
    {
      "name": "personal",
      "address": "me@gmail.com",
      "password": "app-password",
      "provider": "gmail"
    },
    {
      "name": "custom",
      "address": "me@mydomain.com",
      "password": "password",
      "imap_host": "mail.mydomain.com",
      "imap_port": 993,
      "smtp_host": "mail.mydomain.com",
      "smtp_port": 587,
      "smtp_security": "starttls"
    }
  ]
}

Config is reloaded on each tool call, so changes to accounts.json such as rotating send_code take effect without restarting the MCP server.

Fields

Environment variables (single account)

Instead of accounts.json, you can configure a single account via environment variables:

EMAIL_ADDRESS=me@example.com
EMAIL_PASSWORD=password
IMAP_HOST=imap.example.com
SMTP_HOST=smtp.example.com
SMTP_SECURITY=ssl
SEND_AS=alias@example.com
EMAIL_DISPLAY_NAME="Jane Doe"
EMAIL_DESCRIPTION="Primary mailbox"
SEND_CODE=optional