mcp-email-server

IMAP and SMTP via MCP Server

• Github repository: https://github.com/ai-zerolab/mcp-email-server/
• Documentation https://ai-zerolab.github.io/mcp-email-server/

Installation

Manual Installation

We recommend using uv to manage your environment.

Try uvx mcp-email-server@latest ui to config, and use following configuration for mcp client:

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "uvx",
      "args": ["mcp-email-server@latest", "stdio"]
    }
  }
}

This package is available on PyPI, so you can install it using pip install mcp-email-server

After that, configure your email server using the ui: mcp-email-server ui

Environment Variable Configuration

You can also configure the email server using environment variables, which is particularly useful for CI/CD environments like Jenkins. zerolib-email supports both UI configuration (via TOML file) and environment variables, with environment variables taking precedence.

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "uvx",
      "args": ["mcp-email-server@latest", "stdio"],
      "env": {
        "MCP_EMAIL_SERVER_ACCOUNT_NAME": "work",
        "MCP_EMAIL_SERVER_FULL_NAME": "John Doe",
        "MCP_EMAIL_SERVER_EMAIL_ADDRESS": "john@example.com",
        "MCP_EMAIL_SERVER_USER_NAME": "john@example.com",
        "MCP_EMAIL_SERVER_PASSWORD": "your_password",
        "MCP_EMAIL_SERVER_IMAP_HOST": "imap.gmail.com",
        "MCP_EMAIL_SERVER_IMAP_PORT": "993",
        "MCP_EMAIL_SERVER_SMTP_HOST": "smtp.gmail.com",
        "MCP_EMAIL_SERVER_SMTP_PORT": "465"
      }
    }
  }
}

Available Environment Variables

HTTP Transport Security

HTTP transports (sse and streamable-http) validate request Host and Origin headers to protect against DNS rebinding attacks. Localhost is allowed by default. For Docker networks or reverse proxies, configure the expected service names explicitly.

Docker Compose example:

yamlCopy code
services:
  mcp-email-server:
    image: ghcr.io/ai-zerolab/mcp-email-server:latest
    command: ["streamable-http"]
    environment:
      MCP_HOST: 0.0.0.0
      MCP_PORT: 9557
      MCP_ALLOWED_HOSTS: mcp-email-server:*,localhost:*,127.0.0.1:*
      MCP_ALLOWED_ORIGINS: http://mcp-email-server:*,http://localhost:*,http://127.0.0.1:*

Bare host entries such as MCP_ALLOWED_HOSTS=mcp-email-server also allow any port on that host. MCP_ENABLE_DNS_REBINDING_PROTECTION=false, MCP_ALLOWED_HOSTS=*, or MCP_ALLOWED_ORIGINS=* disables Host and Origin validation entirely. Use those options only in isolated local development environments.

IPv6 literals in allowlists should use bracketed notation, such as [::1]:* and http://[::1]:*.

Enabling Attachment Downloads

By default, downloading email attachments is disabled for security reasons. To enable this feature, you can either:

Option 1: Environment Variable

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "uvx",
      "args": ["mcp-email-server@latest", "stdio"],
      "env": {
        "MCP_EMAIL_SERVER_ENABLE_ATTACHMENT_DOWNLOAD": "true"
      }
    }
  }
}

Option 2: TOML Configuration

Add enable_attachment_download = true to your TOML configuration file (~/.config/zerolib/mcp_email_server/config.toml):

tomlCopy code
enable_attachment_download = true

[[emails]]
# ... your email configuration

Once enabled, you can use the download_attachment tool to save email attachments to a specified path.

Saving Sent Emails to IMAP Sent Folder

By default, sent emails are automatically saved to your IMAP Sent folder. This ensures that emails sent via the MCP server appear in your email client (Thunderbird, webmail, etc.).

The server auto-detects common Sent folder names: Sent, INBOX.Sent, Sent Items, Sent Mail, [Gmail]/Sent Mail.

To specify a custom Sent folder name (useful for providers with non-standard folder names):

Option 1: Environment Variable

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "uvx",
      "args": ["mcp-email-server@latest", "stdio"],
      "env": {
        "MCP_EMAIL_SERVER_SENT_FOLDER_NAME": "INBOX.Sent"
      }
    }
  }
}

Option 2: TOML Configuration

tomlCopy code
[[emails]]
account_name = "work"
save_to_sent = true
sent_folder_name = "INBOX.Sent"
# ... rest of your email configuration

To disable saving to Sent folder, set MCP_EMAIL_SERVER_SAVE_TO_SENT=false or save_to_sent = false in your TOML config.

Self-Signed Certificates (e.g., ProtonMail Bridge)

If you're using a local mail server with self-signed certificates (like ProtonMail Bridge), you'll need to disable SSL certificate verification:

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "uvx",
      "args": ["mcp-email-server@latest", "stdio"],
      "env": {
        "MCP_EMAIL_SERVER_IMAP_VERIFY_SSL": "false",
        "MCP_EMAIL_SERVER_SMTP_VERIFY_SSL": "false"
      }
    }
  }
}

Or in TOML configuration:

tomlCopy code
[[emails]]
account_name = "protonmail"
# ... other settings ...

[emails.incoming]
verify_ssl = false

[emails.outgoing]
verify_ssl = false

For separate IMAP/SMTP credentials, you can also use:

• MCP_EMAIL_SERVER_IMAP_USER_NAME / MCP_EMAIL_SERVER_IMAP_PASSWORD
• MCP_EMAIL_SERVER_SMTP_USER_NAME / MCP_EMAIL_SERVER_SMTP_PASSWORD

Then you can try it in Claude Desktop. If you want to intergrate it with other mcp client, run $which mcp-email-server for the path and configure it in your client like:

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "{{ ENTRYPOINT }}",
      "args": ["stdio"]
    }
  }
}

If docker is avaliable, you can try use docker image, but you may need to config it in your client using tools via MCP. The default config path is ~/.config/zerolib/mcp_email_server/config.toml

jsonCopy code
{
  "mcpServers": {
    "zerolib-email": {
      "command": "docker",
      "args": ["run", "-it", "ghcr.io/ai-zerolab/mcp-email-server:latest"]
    }
  }
}

Installing via Smithery

To install Email Server for Claude Desktop automatically via Smithery:

bashCopy code
npx -y @smithery/cli install @ai-zerolab/mcp-email-server --client claude

Usage

Replying to Emails

To reply to an email with proper threading (so it appears in the same conversation in email clients):

1. First, fetch the original email to get its message_id:

pythonCopy code
emails = await get_emails_content(account_name="work", email_ids=["123"])
original = emails.emails[0]

2. Send your reply using in_reply_to and references:

pythonCopy code
await send_email(
    account_name="work",
    recipients=[original.sender],
    subject=f"Re: {original.subject}",
    body="Thank you for your email...",
    in_reply_to=original.message_id,
    references=original.message_id,
)

The in_reply_to parameter sets the In-Reply-To header, and references sets the References header. Both are used by email clients to thread conversations properly.

Development

This project is managed using uv.

Try make install to install the virtual environment and install the pre-commit hooks.

Use uv run mcp-email-server for local development.

Releasing a new version

• Create an API Token on PyPI.
• Add the API Token to your projects secrets with the name PYPI_TOKEN by visiting this page.
• Create a new release on Github.
• Create a new tag in the form *.*.*.

For more details, see here.