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Proton Mail MCP

Proton Mail for Claude, gated by Touch ID — reads run free from a local mirror, and every send re-prompts with the real recipient on screen.

by just-an-oldsalt ↗Email: Mailboxes & DeliveryCommunity

LABSCO SUMMARY

The send prompt names the real recipient, every single time.

The send tool has a TTL of zero, so there is no blanket approval — each send raises a native prompt showing the literal recipients and subject, and your fingerprint is the line between drafted and sent. Around that: the daemon refuses to start if any registered tool lacks an explicit policy entry, screen lock or an idle timer zeroes the in-memory session, and the audit log keeps recipients literal while scrubbing secrets. One trade-off is stated plainly rather than buried — decrypted message bodies are cached in SQLite as plaintext with a TTL, recoverable from an imaged disk until purged.

What it is

A signed and notarized macOS bridge between Proton Mail and Claude, running entirely on your Mac. 34 MCP tools cover reading, searching, organizing, drafting, sending and calendar reading; reads are served from a local SQLite mirror, and everything that changes state is deny-by-default and biometrically gated.

What you get

  • Reading and searching from the local mirror: list, full-text search, read a message, reconstruct a thread, list attachments, list labels and folders, and sync — mail_list, mail_search, mail_read, mail_read_thread, mail_list_attachments, mail_sync
  • Organizing: mark read or unread, move, label and trash — mail_mark_read, mail_mark_unread, mail_move, mail_label, mail_trash
  • Drafts, created, updated, listed and deleted — mail_draft_create, mail_draft_update, mail_draft_list, mail_draft_delete
  • Sending in every shape, each re-prompting: send, reply, reply-all, forward and send-draft — mail_send, mail_reply, mail_reply_all, mail_forward, mail_send_draft
  • Attachments decrypted, downloaded and saved to disk — mail_download_attachment, mail_save_attachment
  • Calendar, read-only: list calendars, browse and search events by date range, and read full event detail — calendar_list, calendar_events, calendar_read_event
  • Per-tool policy in one YAML file — decision, rate limit and allowed recipients, plus an idle-lock timer and a cached-body TTL

Requirements

macOS 13 or newer, and a Proton account — setup signs you in with your Proton password, 2FA and key unlock. Install with brew install --cask proto-mcp, then protonmcp setup, which backfills the local mirror, installs the background daemon and connects Claude Desktop and Claude Code; it is safe to re-run as a repair. protonmcp doctor checks each piece and names the one command that fixes what is broken. After a cask upgrade, run protonmcp daemon restart. Building from source needs Go 1.26.5 or newer and Xcode Command Line Tools. GPLv3.

Setup effort

Follow the published steps — brew tap just-an-oldsalt/proto-mcp

See installation options