Honeycrisp MCP Server

Honeycrisp 🍎

MCP servers for your Mac's real data — Mail, Calendar, files — with safety rails you can audit. Every tool ships governed: dry-run by default, human approval required for anything that sends, moves, or deletes, an audit log of every action, and undo where the platform allows it. Local-first: no accounts, no credentials, no cloud — your data stays on your Mac.

Why this exists

Most MCP servers for personal data are thin wrappers around AppleScript: delete_email, send_message, executed the moment a model calls them. That's a hard thing to trust with an inbox. Honeycrisp inverts the default — a tool call previews what it would do unless you've opted into live mode, and even then every consequential action waits for your explicit approval through a channel the model can't touch. The framework enforcing this is a small library with a test suite proving each guarantee can't be bypassed, and every tool in the suite is built on it.

Install

From npm (recommended):

npm install -g @honeycrisp/mail @honeycrisp/context @honeycrisp/setup
honeycrisp setup

Or from a clone of this repo:

npm install && npm run build
node packages/setup/dist/cli.js setup

The setup wizard walks you through everything, one yes/no question at a time (the default answer is always No — nothing proceeds unless you say so): it registers the servers with Claude Code / Claude Desktop, triggers the macOS permission prompts while you're watching (instead of mid-conversation later), explains the optional Full Disk Access tier for full-text mail search, and can set up the iCloud Agents/ folder and capture schedules. Nothing happens silently; every step it performs is written to the same audit DB the tools use.

What's in the box

How approvals work

Reads are free. Writes that leave your review loop (send, delete, move) are gated: with live mode off (the default), they preview instead of executing; with live mode on, each action individually asks a human through one of:

• a native macOS dialog (default — you're at the Mac),
• a file in an iCloud folder — the request appears on every device you own; move it into Approve or Deny in the Files app. Works from a stock iPhone, no extra apps;
• an MCP elicitation card in clients that support it (opt-in).

No decision, a deleted file, or any ambiguity = denied. Every outcome — executed, denied, dry-run, errored — is a row in a local SQLite audit DB, so you can always answer "what did my tools actually do?"

Privacy model

• No accounts, no credentials, no cloud. Mail access goes through Mail.app, which already has your accounts. iCloud Drive is just a folder; Apple's own sync does the transport. Permissions are macOS's own TCC prompts.
• Pointers, not copies. The context layer stores headers and metadata that reference messages by ID — message bodies are never stored. Delete a message in Mail and the context layer's pointer dangles and gets pruned.
• Content is data, not instructions. Everything read from your mail or files is returned inside a tamper-resistant fence with a standing notice, so text inside an email can't steer the model into acting on it.
• Model use is opt-in and declared. The context layer works fully deterministically with no model configured. If you configure one, its network egress is declared in config and recorded in the audit log on every run.

Design docs

The docs/ directory has one design doc per component, including the framework contract (01), and the remote-access design (05) for reaching these servers from phone/web clients. NOTES.md is the running engineering log: decisions with dates, open questions, and field-test findings.

License

MIT. See LICENSE.