jxa-mail-mcp 0.3.0

Fast MCP server for Apple Mail with FTS5 search index

JXA Mail MCP

A fast MCP (Model Context Protocol) server for Apple Mail, using optimized JXA (JavaScript for Automation) scripts with batch property fetching for 87x faster performance, plus an optional FTS5 search index for 700-3500x faster body search (~2ms vs ~7s).

Features

Email Tools

• list_accounts - List all configured email accounts
• list_mailboxes - List mailboxes for an account
• get_emails - Fetch emails from any mailbox with pagination
• get_email - Fetch a single email with full body content
• get_todays_emails - Fetch all emails received today
• get_unread_emails - Fetch unread emails
• get_flagged_emails - Fetch flagged emails
• search_emails - Search emails by subject or sender
• fuzzy_search_emails - Typo-tolerant search using trigram + Levenshtein matching
• search_email_bodies - Full-text search within email bodies (~100x faster with index)

Index Tools

• index_status - Get FTS5 index statistics
• sync_index - Sync new emails to the index
• rebuild_index - Force rebuild the index from disk

Installation

No installation required

Use pipx run to run directly from PyPI:

pipx run jxa-mail-mcp

With pipx (optional)

For faster startup, install globally:

pipx install jxa-mail-mcp

From source

Requires Python 3.13+ and uv:

git clone https://github.com/imdinu/jxa-mail-mcp
cd jxa-mail-mcp
uv sync

Quick Start

1. Add to Claude Code

{
  "mcpServers": {
    "mail": {
      "command": "jxa-mail-mcp"
    }
  }
}

2. Build the Search Index (Optional but Recommended)

For instant body search (~2ms instead of ~7s), build the FTS5 index:

# Grant Full Disk Access to Terminal first:
# System Settings → Privacy & Security → Full Disk Access → Add Terminal

jxa-mail-mcp index --verbose
# → Indexed 22,696 emails in 1m 7.6s
# → Database size: 130.5 MB

3. Use with Claude

Once configured, you can search emails, get today's messages, find unread emails, and more through natural conversation.

CLI Commands

jxa-mail-mcp            # Run MCP server (default)
jxa-mail-mcp serve      # Run MCP server explicitly
jxa-mail-mcp --watch    # Run with real-time index updates
jxa-mail-mcp index      # Build search index from disk
jxa-mail-mcp status     # Show index statistics
jxa-mail-mcp rebuild    # Force rebuild index

Real-Time Index Updates

Use --watch to automatically update the index when new emails arrive:

jxa-mail-mcp --watch
# or
jxa-mail-mcp serve --watch

The file watcher monitors ~/Library/Mail/V10/ for .emlx changes and updates the index in real-time. Requires Full Disk Access.

Configuration

Environment Variables

Variable	Default	Description
JXA_MAIL_DEFAULT_ACCOUNT	First account	Default email account
JXA_MAIL_DEFAULT_MAILBOX	Inbox	Default mailbox
JXA_MAIL_INDEX_PATH	~/.jxa-mail-mcp/index.db	Index database location
JXA_MAIL_INDEX_MAX_EMAILS	5000	Max emails per mailbox to index
JXA_MAIL_INDEX_STALENESS_HOURS	24	Hours before index is stale

Claude Code Config

{
  "mcpServers": {
    "mail": {
      "command": "jxa-mail-mcp",
      "env": {
        "JXA_MAIL_DEFAULT_ACCOUNT": "Work"
      }
    }
  }
}

FTS5 Search Index

The FTS5 index makes search_email_bodies() ~100x faster by pre-indexing email content.

How It Works

1. Build from disk: jxa-mail-mcp index reads .emlx files directly (~30x faster than JXA)
2. Startup sync: New emails are synced via JXA when the server starts
3. Real-time updates: --watch flag enables file watcher for automatic index updates
4. Fast search: Queries use SQLite FTS5 with BM25 ranking

Requirements

Building the index requires Full Disk Access for Terminal:

1. Open System Settings
2. Go to Privacy & Security → Full Disk Access
3. Add and enable Terminal.app (or your terminal emulator)
4. Restart terminal

The MCP server itself does NOT need Full Disk Access (uses JXA for syncing).

Performance Comparison

Operation	Without Index	With Index	Speedup
Body search	~7,000ms	~2-10ms	700-3500x
Initial index build	N/A	~1-2 min	One-time
Startup sync	N/A	~1-2s	Incremental
Index size	N/A	~6 KB/email	-

Real-World Benchmarks (22,696 emails)

Query	Results	Time
"invoice"	20	2.5ms
"meeting tomorrow"	20	1.3ms
"password reset"	20	0.6ms
"shipping confirmation"	10	4.1ms

Architecture

src/jxa_mail_mcp/
├── __init__.py         # CLI entry point
├── cli.py              # CLI commands (index, status, rebuild)
├── server.py           # FastMCP server and MCP tools
├── config.py           # Environment variable configuration
├── builders.py         # QueryBuilder for constructing JXA scripts
├── executor.py         # Async JXA script execution utilities
├── index/              # FTS5 search index module
│   ├── __init__.py     # Exports IndexManager
│   ├── schema.py       # SQLite schema, migrations, and utilities
│   ├── manager.py      # IndexManager class
│   ├── disk.py         # Direct .emlx file reading
│   ├── sync.py         # JXA-based incremental sync
│   ├── search.py       # FTS5 search functions
│   └── watcher.py      # Real-time file watcher
└── jxa/
    ├── __init__.py     # Exports MAIL_CORE_JS
    └── mail_core.js    # Shared JXA utilities library

Design Principles

1. Separation of concerns: Python handles logic/types, JavaScript handles Mail.app interaction
2. Builder pattern: QueryBuilder constructs optimized JXA scripts programmatically
3. Shared JS library: mail_core.js provides reusable utilities injected into all scripts
4. Hybrid indexing: Disk reading for speed, JXA for incremental updates
5. Async execution: All JXA calls use asyncio.create_subprocess_exec for non-blocking I/O
6. Type safety: Python type hints and TypedDict for clear API contracts

Hybrid Access Pattern

Access Method	Use Case	Latency	When Used
JXA (Live)	Real-time ops, small queries	~100-300ms	get_email(), list_mailboxes()
FTS5 (Cached)	Body search, complex filtering	~2-10ms	search_email_bodies()
Disk (Batch)	Initial indexing	~15ms/100 emails	jxa-mail-mcp index

Performance

Batch Property Fetching (87x faster)

Naive AppleScript/JXA iteration is extremely slow because each property access triggers a separate Apple Event IPC round-trip. We use batch property fetching instead:

// FAST: ~0.6 seconds (87x faster than per-message iteration)
const msgs = inbox.messages;
const senders = msgs.sender();   // Single IPC call returns array
const subjects = msgs.subject(); // Single IPC call returns array

Benchmark Results

Method	Time	Speedup
AppleScript (per-message)	54.1s	1x
JXA (per-message)	53.9s	1x
JXA (batch fetching)	0.62s	87x

Body Search with FTS5 Index

Search Type	Without Index	With Index	Speedup
Body search	~7,000ms	~2-10ms	700-3500x
Metadata search	~100ms	~100ms	-

The FTS5 index uses:

• Porter stemmer: "meeting" matches "meetings", "met"
• BM25 ranking: Results sorted by relevance (term frequency × inverse document frequency)
• External content table: Shares storage with main emails table for efficiency

Fuzzy Search Performance

Fuzzy search uses trigrams for fast candidate selection and Levenshtein distance for accurate ranking:

Search Type	Time (~6,000 emails)
Regular search	~360ms
Fuzzy search	~480ms (+33%)

Development

uv sync
uv run ruff check src/
uv run ruff format src/

# Run unit tests
uv run pytest

# Run tests with verbose output
uv run pytest -v

# Manual test
uv run python -c "
import asyncio
from jxa_mail_mcp.server import list_accounts, get_todays_emails
print('Accounts:', len(asyncio.run(list_accounts())))
print('Today:', len(asyncio.run(get_todays_emails())))
"

# Test index
uv run python -c "
from jxa_mail_mcp.index import IndexManager
m = IndexManager.get_instance()
if m.has_index():
    stats = m.get_stats()
    print(f'Indexed: {stats.email_count} emails')
"

Security

Implemented Protections

Threat	Mitigation	Location
SQL Injection	Parameterized queries	search.py, sync.py
JXA Injection	json.dumps() serialization	sync.py, executor.py
FTS5 Query Injection	Special character escaping	search.py
XSS via HTML Emails	BeautifulSoup HTML parsing	disk.py
DoS via Large Files	25 MB file size limit	disk.py
Path Traversal	Path validation in watcher	watcher.py
Data Exposure	Database created with 0600 permissions	schema.py

Troubleshooting

ModuleNotFoundError after install

If you get ModuleNotFoundError: No module named 'jxa_mail_mcp' even though the package is installed, reset the virtual environment:

rm -rf .venv
uv sync --upgrade

Full Disk Access denied

The jxa-mail-mcp index command requires Full Disk Access to read Mail.app's data files. Grant access in:

System Settings → Privacy & Security → Full Disk Access → Add Terminal

Then restart your terminal.

License

GPL-3.0-or-later