owlpost

A high-fidelity IMAP/SMTP MCP server for iCloud, Gmail, and other mail providers. Built because every other email MCP server I tried got tripped up by real-world IMAP quirks (CRLF line endings, RFC822 vs BODY.PEEK[], provider-specific Sent folders, multi-word search values).

owlpost is the one I actually use day-to-day from Claude Code to read, search, follow conversations, and send mail.

Features

• Multi-account — configure as many mailboxes as you want, switch by name

• iCloud and Gmail tested end-to-end, with provider-specific quirks handled:

  • iCloud's RFC822 fetch returns empty bodies → uses BODY.PEEK[]

  • iCloud's IMAP APPEND requires CRLF line endings → all outbound mail uses policy.SMTP

  • iCloud's SMTP doesn't auto-save sent mail → owlpost APPENDs to Sent for you

  • Gmail's SMTP does auto-save → owlpost skips the duplicate APPEND

  • Folder names auto-discovered via RFC 6154 SPECIAL-USE (no hardcoding Sent Messages vs [Gmail]/Sent Mail)

• Conversation following — Gmail's X-GM-THRID extension where available, otherwise a generic Message-ID/References BFS across folders

• Reliable connections — short-lived per-operation IMAP sessions instead of long-lived ones that drop randomly

• MIME-aware — parses multipart messages, decodes headers, lists attachments, downloads them to disk

• Threaded reply/forward — preserves In-Reply-To/References, quotes the original

Related MCP server: email-mcp

Tools

Install

The recommended way is to not install at all — let uvx fetch and cache it on first use. This keeps the package always up-to-date and avoids polluting your global Python environment:

# Run directly — uvx fetches from PyPI and caches.
uvx --from owlpost owlpost

If you'd rather have a stable binary on your PATH:

# Persistent install with uv (recommended)
uv tool install owlpost

# Or plain pip
pip install owlpost

Either way you'll end up with an owlpost command that speaks MCP over stdio.

Configure

Copy accounts.example.toml to ~/.config/owlpost/accounts.toml and fill in your credentials. Use app-specific passwords, not your real password:

• iCloud: account.apple.com → Sign-In and Security → App-Specific Passwords

• Gmail: myaccount.google.com/apppasswords (2FA must be enabled)

[accounts.icloud]
email = "you@icloud.com"
password = "xxxx-xxxx-xxxx-xxxx"
provider = "icloud"
imap_host = "imap.mail.me.com"
imap_port = 993
smtp_host = "smtp.mail.me.com"
smtp_port = 587
auto_save_sent = true   # iCloud SMTP doesn't auto-save sent

[accounts.gmail]
email = "you@gmail.com"
password = "xxxx xxxx xxxx xxxx"
provider = "gmail"
imap_host = "imap.gmail.com"
imap_port = 993
smtp_host = "smtp.gmail.com"
smtp_port = 587
auto_save_sent = false  # Gmail SMTP auto-saves

You can override the config path with the OWLPOST_CONFIG environment variable.

Use with Claude Code

Add to ~/.claude.json under mcpServers. The uvx form is recommended — it fetches owlpost from PyPI on first launch, caches it, and keeps you on the latest version with no manual install step:

{
  "mcpServers": {
    "owlpost": {
      "type": "stdio",
      "command": "uvx",
      "args": ["--from", "owlpost", "owlpost"],
      "env": {}
    }
  }
}

If uvx isn't on Claude Code's PATH you may need to use the absolute path (typically ~/.local/bin/uvx).

Alternatively, if you installed with uv tool install owlpost or pip install owlpost, point command directly at the resulting binary:

{
  "mcpServers": {
    "owlpost": {
      "type": "stdio",
      "command": "owlpost",
      "args": [],
      "env": {}
    }
  }
}

Restart Claude Code and the tools will appear under the owlpost namespace.

Use with Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "owlpost": {
      "command": "uvx",
      "args": ["--from", "owlpost", "owlpost"]
    }
  }
}

Use with other MCP clients

owlpost speaks the standard MCP stdio transport — any MCP-compatible client can talk to it by spawning either uvx --from owlpost owlpost or, if installed, the bare owlpost binary.

Examples

Once registered, you can ask Claude things like:

• "Find emails from priya about the kids' school in the last month"

• "Show me the full thread for the latest mortgage email"

• "Reply to the most recent message from the landlord saying I'll be in touch tomorrow"

• "Forward the Manulife policy PDFs to Mom and Dad with Priyanka in CC"

• "Save the attachment from the Toronto Hydro bill to ~/Downloads"

Provider notes

iCloud

• Use an app-specific password, not your Apple ID password.

• iCloud throttles aggressive reconnection. owlpost uses short-lived per-op sessions but doesn't pool — if you get SSLEOFError: EOF, back off for ~30 seconds.

• Sent folder is Sent Messages, Trash is Deleted Messages. Both are auto-detected.

Gmail

• Requires 2FA and an app password.

• IMAP must be enabled in Gmail settings → Forwarding and POP/IMAP.

• owlpost uses Gmail's X-GM-THRID extension for reliable thread detection.

Proton Mail (via Proton Bridge)

Proton only exposes IMAP/SMTP through the Proton Bridge app, which runs on localhost with a self-signed certificate and speaks STARTTLS on non-standard ports. Configure with:

• provider = "generic"

• imap_host = "127.0.0.1", imap_port = 1143, imap_security = "starttls"

• smtp_host = "127.0.0.1", smtp_port = 1025, smtp_security = "starttls"

• tls_verify = false — required because Bridge's cert is self-signed

• Use the Bridge-generated mailbox password (not your Proton account password)

Other providers

Set provider = "generic" and configure imap_host, smtp_host, ports, imap_security / smtp_security (starttls or ssl), and tls_verify (set false for self-signed certs). Folder roles will still be auto-detected if your provider supports SPECIAL-USE (most modern ones do).

Development

git clone https://github.com/smankoo/owlpost
cd owlpost
uv venv
uv pip install -e .

Run the server directly to verify it starts:

.venv/bin/owlpost
# (waits for MCP stdio input)

Publishing

Releases go to PyPI. From a clean tree on main:

# 1. Bump version in pyproject.toml
# 2. Commit the bump
# 3. Build the sdist + wheel
uv build

# 4. Upload to PyPI (requires ~/.pypirc with an API token)
uv publish

# 5. Tag and push
git tag v0.1.x
git push && git push --tags

uv build writes to dist/. uv publish reads credentials from ~/.pypirc (expects [pypi] with username = __token__ and password = pypi-...). uvx users pick up the new version automatically on next launch.

License

MIT — see LICENSE.