SkillFoxx

Proton Mail Bridge Client MCP

An MCP server and CLI for Proton Mail through Proton Bridge: search, drafts and mail triage with read-only and drafts safety modes

  • 90 ★ on the repository
  • Last commit
  • MIT
MCP server

Broad access

Why this level

  • The server reads all your mail and can send and delete messages in `full` mode, and message text is visible to the model.
  • Messages can carry embedded instructions, so use `drafts` or `read-only` when triaging mail from others.
All reasons and checks

googlarz/proton-mail-bridge-clientAuthor:googlarz

Install

In your terminal, with SkillFoxx CLI

npx skillfoxx add mcp/proton-mail-bridge-client

Detects the agents on your machine, shows the access level and pins the version.

Other ways to install

Access and checks

How we review

Broad accessThe tool can change data, run commands or handle secrets.

  • The server reads all your mail and can send and delete messages in `full` mode, and message text is visible to the model.
  • Messages can carry embedded instructions, so use `drafts` or `read-only` when triaging mail from others.

This is third-party code. Review the repository files before installing.

What it does

The server connects Claude Desktop, Cline and other MCP clients to Proton Mail through the local Proton Bridge. It talks only to Bridge on `127.0.0.1` and keeps the mail index on your disk. The agent searches mail, reads threads, drafts replies, sends and files messages into folders; the full set has 129 tools, and `PROTONMAIL_TOOL_TIER=core` trims it to 25. The mode comes from `PROTONMAIL_MODE`: `read-only` only reads, `drafts` prepares drafts with no sending, moving or deleting, `assisted` asks for confirmation and `full` allows everything. With `PROTONMAIL_APPROVAL=elicit` the client asks the human to confirm. Changes can go to a hash-chained audit log. The same tools are available as a CLI for scripts and schedulers, and there is a morning digest.

Who it is for. Proton Mail users who want Claude to triage the inbox and draft replies while keeping sending and deletion under their control.

Good fit when

  • In the morning you want a digest of new mail and the threads waiting on a reply
  • The agent finds the last email from a contact and drafts a reply for you to review
  • Mail with attachments from this month has to be found in a large local index
  • The same operations are called from cron and scripts without Claude through the CLI

Not a fit when

  • You need Proton Mail access without Proton Bridge running, as the server works only through it
  • Mail cannot be shown to an outside model and you have no local model, since message text goes to the model provider
  • You want a pure send-immediately mode in an unattended pipeline with no audit

Example request

Give me a digest of today's inbox, flag mail that needs a reply and draft a reply to Alice

MCP

Transport
stdio
Authentication
API key

Environment variables

PROTONMAIL_USERNAME required
Proton Mail address.
PROTONMAIL_PASSWORD required, secret
Bridge password from the Proton Bridge app.
PROTONMAIL_MODE
Safety mode: read-only, drafts, assisted or full.
PROTONMAIL_APPROVAL
How sending and deleting are approved: elicit or require.

Limitations

Proton Mail Bridge must be installed and running, with the Bridge password, which is not your Proton account password. The package needs Node.js 22 or newer. If `PROTONMAIL_MODE` is unset the server runs in `full` mode and can send mail without confirmation, while a fresh `setup-claude-desktop` install writes `drafts`. Message text the model reads goes to the model provider unless the model is local. Approval through `elicit` depends on client support, and only `require` fails closed.

How to disable. Remove the `proton-mail-bridge` entry from the MCP client configuration and run `npm uninstall -g proton-mail-bridge-client`. Erase the local index and audit log separately.

FAQ

How do I connect the server to Claude Desktop?

Install the package with `npm install -g proton-mail-bridge-client` and run `proton-mail-bridge-client setup-claude-desktop`, which checks Bridge ports and writes the config. An `.mcpb` bundle is also in the releases. Fully restart Claude Desktop.

Which safety mode should I start with?

`PROTONMAIL_MODE=drafts`: the agent reads, searches and prepares drafts but sends and deletes nothing. For pure reading there is `read-only`.

What is the Bridge password?

A separate password shown by the Proton Bridge app in your account settings. The server does not use your Proton account password.

Does the server guard against instructions inside emails?

The server tells the client not to obey instructions found inside a message. That is a default safeguard and no guarantee, so mode restrictions are more reliable.

Does the server work with clients other than Claude Desktop?

Yes, Cline and any MCP client will do. The server command in the configuration is `proton-mail-bridge-mcp`, with credentials set through `PROTONMAIL_*` variables.

Discussion

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README in short

The README covers installation, the `.mcpb` and npm routes, safety modes, the audit log and the CLI. Separate documents cover the threat model, fully local use and installation without a terminal.

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