Proton Workflow Connector

Name: Proton Workflow Connector
Author: NtrpyDev

by NtrpyDevversion 1.3.0i★ –iRuns on your computer

Registry nameio.github.NtrpyDev/proton-workflow-connector

Install

Overview

Description from the maker (original English)

Unofficial self-hosted MCP connector for Proton Mail Bridge and SimpleLogin.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiVery new↓ 12/wk · ★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other
You need to fill in: PROTON_BRIDGE_USERNAME, PROTON_BRIDGE_PASSWORD, PROTON_BRIDGE_EMAIL, SIMPLELOGIN_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: PROTON_BRIDGE_USERNAME, PROTON_BRIDGE_PASSWORD, PROTON_BRIDGE_EMAIL, SIMPLELOGIN_API_KEY

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

PyPIPython’s uv installed (for the uvx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "proton-workflow-connector": {
      "command": "uvx",
      "args": [
        "proton-workflow-connector"
      ],
      "env": {
        "PROTON_BRIDGE_USERNAME": "your-value",
        "PROTON_BRIDGE_PASSWORD": "your-value",
        "PROTON_BRIDGE_EMAIL": "your-value",
        "SIMPLELOGIN_API_KEY": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add proton-workflow-connector --env PROTON_BRIDGE_USERNAME=your-value --env PROTON_BRIDGE_PASSWORD=your-value --env PROTON_BRIDGE_EMAIL=your-value --env SIMPLELOGIN_API_KEY=your-value -- uvx proton-workflow-connector

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "proton-workflow-connector": {
      "command": "uvx",
      "args": [
        "proton-workflow-connector"
      ],
      "env": {
        "PROTON_BRIDGE_USERNAME": "your-value",
        "PROTON_BRIDGE_PASSWORD": "your-value",
        "PROTON_BRIDGE_EMAIL": "your-value",
        "SIMPLELOGIN_API_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "proton-workflow-connector": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "proton-workflow-connector"
      ],
      "env": {
        "PROTON_BRIDGE_USERNAME": "your-value",
        "PROTON_BRIDGE_PASSWORD": "your-value",
        "PROTON_BRIDGE_EMAIL": "your-value",
        "SIMPLELOGIN_API_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

PROTON_BRIDGE_USERNAME required env
Bridge IMAP/SMTP username (from the Bridge app)
PROTON_BRIDGE_PASSWORD secret required env
Bridge-generated password (never your Proton account password)
PROTON_BRIDGE_EMAIL required env
Primary Proton address served by Bridge
SIMPLELOGIN_API_KEY secret env
SimpleLogin API key; omit to disable alias tools

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account NtrpyDev, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 18474 servers in this category
Published to the registry more recently than 13% of the other 18474 servers in this category
Basic checks equal to or better than 100% of the other 18474 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Proton Workflow Connector safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: PROTON_BRIDGE_USERNAME, PROTON_BRIDGE_PASSWORD, PROTON_BRIDGE_EMAIL, SIMPLELOGIN_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.3.0) reached the registry 4 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Brontide agent arena

Alternatives

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by beeswaxpatVery newUpdated today

Runs in the cloud✓ brontide.live

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Proton Workflow Connector

Proton Workflow Connector (PWC) is a self-hosted MCP connector for reading, sending, organizing, and automating Proton Mail through Proton Mail Bridge. It works with any MCP client or local agent runtime that can launch a stdio server or call a Streamable HTTP MCP endpoint. SimpleLogin support is optional.

This is an unofficial project. It is not affiliated with, endorsed by, or sponsored by Proton AG. The connector uses Bridge-generated IMAP/SMTP credentials. It does not accept Proton account passwords or store Proton login sessions.

Quick start · Example workflows · Capabilities · Automations · Security · Documentation · Buy Me a Coffee

Why use it?

Use one local server for the mail work agents usually have to piece together:

Search, read, send, reply, forward, draft, label, archive, and download attachments through 53 Proton Mail tools.
Require confirmation for destructive tools, preview sends and destructive operations with dry_run, sanitize outbound HTML by default, bound bulk operations, and allow only configured sender addresses.
React to new mail or SimpleLogin aliases through MCP polling or a background watcher that can call a webhook, append JSONL, or run a command.
Add 13 SimpleLogin tools when you want alias, contact, and mailbox management.
Connect over stdio, localhost Streamable HTTP, or OAuth-protected hosted HTTP.

The server exposes 68 tools in total. See the complete tool reference.

How it works

PWC is an MCP server. Your client starts it over stdio or connects to it over Streamable HTTP.

The connector talks to Proton Mail Bridge over local IMAP/SMTP. Bridge must be installed, signed in, and running on the same machine as the connector. One connector process serves one Bridge account.

SimpleLogin is optional. If SIMPLELOGIN_API_KEY is set, PWC adds alias, contact, mailbox, and new-alias polling tools. If it is unset, the Proton Mail tools still work.

For automation, run proton-workflow-watch or call the polling tools from your MCP client. Watcher output can go to a webhook, a JSONL file, or a command.

Quick start

Prerequisites

Python 3.11 or newer
Proton Mail Bridge, signed in and running
The IMAP/SMTP host, ports, username, and generated password shown by Bridge
A SimpleLogin API key only if you want the optional SimpleLogin tools

1. Install

git clone https://github.com/NtrpyDev/proton-workflow-connector.git

cd proton-workflow-connector python -m venv .venv source .venv/bin/activate python -m pip install .

On Windows PowerShell, activate the environment with .venv\Scripts\Activate.ps1.

2. Configure Bridge credentials

Keep the environment file outside the repository:

mkdir -p ~/.config/proton-workflow-connector

cp .env.example ~/.config/proton-workflow-connector/env chmod 600 ~/.config/proton-workflow-connector/env

Edit the copied file with the connection details shown in Proton Mail Bridge. Set PROTON_BRIDGE_EMAIL to the default sender and list every permitted sender address in PROTON_BRIDGE_SENDER_ADDRESSES.

3. Run the connector

proton-workflow-connector --transport stdio \

--env-file ~/.config/proton-workflow-connector/env

4. Connect an MCP client

Any MCP client or local agent runtime can use PWC as long as it supports stdio or Streamable HTTP:

stdio: run proton-workflow-connector --transport stdio --env-file ...
HTTP: run the connector with --transport streamable-http and point the client at /mcp

Claude Code stdio example:

claude mcp add --transport stdio --scope user proton-workflow \

-- "$PWD/.venv/bin/proton-workflow-connector" --transport stdio \ --env-file ~/.config/proton-workflow-connector/env

Codex stdio example:

[mcp_servers.proton_workflow]

command = "/absolute/path/to/repo/.venv/bin/proton-workflow-connector" args = [ "--transport", "stdio", "--env-file", "/absolute/path/to/private/proton-workflow-connector-env" ] default_tools_approval_mode = "prompt" startup_timeout_sec = 20 tool_timeout_sec = 120

Run server_status after connecting. It checks IMAP, SMTP, SimpleLogin, OAuth configuration, and the server version without returning secrets. Then run list_folders; Bridge folder names vary by account and version.

See MCP client setup for generic client configuration, localhost HTTP, hosted Streamable HTTP, Codex, Claude Code, and the plugin wrapper.

Example workflows

Once connected, ask your MCP client to:

"List my mail folders and show the unread count for each."
"Find unread invoices from the last 30 days without marking them read."
"Draft a reply to the latest message in this thread, but do not send it."
"Download the PDF attachments from this message."
"Archive these message UIDs after showing me the exact list."
"Create a SimpleLogin alias for shopping and add a contact for this merchant."
"Poll for new mail from billing@vendor.example using the invoices cursor."

The connector returns structured data to the MCP client. The client decides how to present it and when to request approval for actions.

Capabilities

Area	Included operations
Search and reading	Search one folder or all selectable folders, read messages and threads, inspect headers, and download attachments
Sending and drafts	Send, reply, reply-all, forward, create and update drafts, use allowed alternate senders, and attach files
Organization	Create and manage folders, apply Proton labels, change flags, archive, move, copy, restore, and manage Spam or Trash
Bounded bulk actions	Preview, mark, star, move, copy, archive, trash, restore, or permanently delete explicit UID lists
Automations	Poll persistent cursors or push new-message and new-alias events to a webhook, JSONL file, or command
SimpleLogin	Inspect account data and manage aliases, contacts, and mailboxes with an optional API key
Deployment	Local stdio, localhost Streamable HTTP, or OAuth/OIDC-protected hosted HTTP

Proton Contacts are not included because Proton Mail Bridge does not expose them.

Automations

The background watcher polls for new mail or newly created SimpleLogin aliases and emits one event per new item:

proton-workflow-watch \

--env-file ~/.config/proton-workflow-connector/env \ --folder INBOX \ --webhook-url https://example.com/hooks/proton \ --interval 60

Key behavior:

The first run establishes a baseline and does not replay the existing mailbox.
Persistent cursors survive restarts and account for IMAP UIDVALIDITY changes.
Webhook delivery is at-least-once, with retries, exponential backoff, and dead-letter handling.
An optional HMAC-SHA256 signature lets webhook receivers verify each event.
Events contain message metadata only; bodies and attachments remain available on demand through MCP tools.
JSON rules can run several independently filtered triggers from one watcher.
--dry-run shows which events and rule actions would fire without delivering, acting, or advancing cursors.

Read Triggers and webhooks for event schemas, filters, delivery guarantees, signature verification, rules, and systemd examples.

Security model

This connector processes private mail. Its defaults and boundaries are intentionally explicit:

Prefer local stdio. Bridge and the connector should stay on the same trusted machine whenever possible.
Keep credentials private. Store Bridge-generated credentials and optional API keys outside Git with user-only permissions.
Confirm destructive actions. Permanent deletion, empty-folder operations, folder deletion, and alias deletion require confirm=true after explicit user intent.
Preview before mutating. Sends, forwards, replies, bulk actions, permanent delete, and empty-folder operations support dry_run=true previews.
Treat mail as untrusted. Read/search results mark email content as content_trust: "untrusted", and outbound HTML is sanitized unless trusted_html=true.
Bound bulk operations. Bulk tools require explicit numeric UIDs and default to a maximum of 50 messages per call.
Restrict senders. Mail can only be sent from PROTON_BRIDGE_EMAIL or an address in PROTON_BRIDGE_SENDER_ADDRESSES.
Protect remote access. Non-local HTTP deployments require deliberate Host/Origin policy; internet deployments require HTTPS and an external OAuth/OIDC provider.
Limit exposed data. Optional audit records exclude addresses, message bodies, attachments, credentials, and tokens.
Treat events as untrusted input. Email subjects and alias names can be attacker-controlled; webhook receivers and commands must validate event fields.

Read SECURITY.md before using real mail and Hosted HTTP setup before exposing the connector beyond localhost.

Known boundaries

Proton Mail Bridge must remain running while the connector or watcher is active.
One server process connects to one Bridge account.
Proton Contacts, native scheduled sending, filters, account settings, and key management are not exposed by Bridge and are not emulated.
New-mail and new-alias triggers use polling because Proton and SimpleLogin do not provide a compatible push API.
Trigger events include metadata, not message bodies or attachments.
All Mail is a virtual read-only Bridge mailbox; start move and permanent-delete operations from a writable folder.

Documentation

Guide	Use it for
Setup	Bridge configuration, private environment files, folder names, and network modes
Tool reference	All 68 MCP tools, arguments, safety limits, and boundaries
Client setup	Generic MCP clients, local agents, Codex, Claude Code, plugins, and Streamable HTTP
Triggers and webhooks	Watcher rules, payloads, delivery behavior, and signature verification
Hosted HTTP	OAuth/OIDC, HTTPS, Host/Origin validation, scopes, audit logs, and systemd
Integration tests	Live Bridge and SimpleLogin verification

Official upstream references:

Development

Install the development dependencies and run the local checks:

python -m pip install -e ".[dev]"

ruff check . ruff format --check . pytest python -m compileall -q src pip-audit gitleaks detect --redact --config .gitleaks.toml

Tests use synthetic data and do not require access to a real mailbox. Live checks are documented separately in Integration tests.

See CONTRIBUTING.md for contribution and privacy requirements. Report security issues privately as described in SECURITY.md.

License

MIT. See LICENSE.

Proton Workflow Connector

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Brontide agent arena

README from the maker

Proton Workflow Connector

Why use it?

How it works

Quick start

Prerequisites

1. Install

2. Configure Bridge credentials

3. Run the connector

4. Connect an MCP client

Example workflows

Capabilities

Automations

Security model

Known boundaries

Documentation

Development

License