FieldCure.Mcp.Outbox 0.1.0

FieldCure MCP Outbox Server

A multi-channel messaging Model Context Protocol (MCP) server that sends messages through Slack, Telegram, Email (SMTP), and KakaoTalk. Built with C# and the official MCP C# SDK.

Features

• 4 messaging channels — Slack, Telegram, SMTP (Gmail, Outlook, Microsoft 365, Naver), KakaoTalk
• 4 MCP tools — list_channels, add_channel, send_message, remove_channel
• Secure credential storage — secrets stored in Windows Credential Manager (DPAPI), never exposed to LLM
• CLI channel setup — interactive console for credential entry, launched as a subprocess
• SMTP presets — Gmail, Outlook, Microsoft 365, Naver with one-command setup
• KakaoTalk OAuth — localhost callback flow with automatic token refresh
• Telegram Client API — send to Saved Messages via WTelegramClient
• Stdio transport — standard MCP subprocess model via JSON-RPC over stdin/stdout

Installation

dotnet tool (recommended)

dotnet tool install -g FieldCure.Mcp.Outbox

After installation, the fieldcure-mcp-outbox command is available globally.

From source

git clone https://github.com/fieldcure/fieldcure-mcp-outbox.git
cd fieldcure-mcp-outbox
dotnet build

Requirements

• .NET 8.0 Runtime or later
• Windows (required for Credential Manager)

Configuration

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "outbox": {
      "command": "fieldcure-mcp-outbox"
    }
  }
}

VS Code (Copilot)

Add to .vscode/mcp.json:

{
  "servers": {
    "outbox": {
      "command": "fieldcure-mcp-outbox"
    }
  }
}

From source (without dotnet tool)

{
  "mcpServers": {
    "outbox": {
      "command": "dotnet",
      "args": [
        "run",
        "--project", "C:\\path\\to\\fieldcure-mcp-outbox\\src\\FieldCure.Mcp.Outbox"
      ]
    }
  }
}

Tools

Channel Setup

All channel credentials are stored securely in Windows Credential Manager (DPAPI). No secrets are exposed in conversation history or config files.

Slack

What it does: Sends messages to a Slack channel via Bot API.

Prerequisites:

1. A Slack workspace (free plan is fine, single-person workspace works)
2. A Slack App with Bot Token

Setup Steps:

1. Go to api.slack.com/apps and click Create New App → From scratch
2. Enter an App Name (e.g. "AssistStudio") and select your workspace
3. In the left menu, go to OAuth & Permissions
4. Under Bot Token Scopes, click Add an OAuth Scope and add chat:write
5. Scroll up and click Install to Workspace → Allow
6. Copy the Bot User OAuth Token (xoxb-...)
7. Important: In your Slack workspace, invite the bot to the channel where you want to send messages. Type /invite @YourBotName in the channel.

Add Channel:

fieldcure-mcp-outbox add slack

You will be prompted for:

• Channel name: The default Slack channel name (e.g. general, dev-alerts)
• Bot Token: The xoxb-... token from step 6

Note: The bot must be invited to the channel before it can send messages. Type /invite @YourBotName in the Slack channel.

Telegram

What it does: Sends messages to yourself (Saved Messages) via Telegram Client API.

Prerequisites:

1. A Telegram account with a registered phone number
2. Telegram API credentials (API ID and API Hash)

Setup Steps:

1. Go to my.telegram.org and log in with your phone number
2. Click API development tools
3. Fill in the form:
   • App title: Any name (e.g. "AssistStudio")
   • Short name: 5-32 alphanumeric characters (e.g. "AStudio")
   • Platform: Desktop
   • URL / Description: Leave empty
4. Click Create application
5. Note down the API ID (numeric) and API Hash (string)

Note: Test/Production configuration values on the same page are NOT needed.

Add Channel:

fieldcure-mcp-outbox add telegram

You will be prompted for:

• API ID: The numeric ID from step 5
• API Hash: The hash string from step 5
• Phone: Your phone number in international format (e.g. 8210xxxxxxxx)
• Verification code: Enter the code sent to your Telegram app or via SMS

A session file is created after successful authentication. Subsequent use does not require re-authentication.

SMTP (Email)

What it does: Sends emails via SMTP. Supports Gmail, Outlook, Microsoft 365, Naver, and custom SMTP servers.

Add Channel:

fieldcure-mcp-outbox add smtp

A provider menu will be displayed:

Select provider:
  1. Gmail          (smtp.gmail.com)
  2. Outlook        (smtp-mail.outlook.com)
  3. Microsoft 365  (smtp.office365.com)
  4. Naver          (smtp.naver.com)
  5. Custom

You can also use shortcut commands:

fieldcure-mcp-outbox add gmail
fieldcure-mcp-outbox add outlook
fieldcure-mcp-outbox add microsoft365
fieldcure-mcp-outbox add naver

Gmail

Prerequisites:

1. A Gmail account with 2-Step Verification enabled
2. An App Password (NOT your regular Google password)

Getting an App Password:

1. Go to myaccount.google.com/security
2. Ensure 2-Step Verification is ON
3. Go to myaccount.google.com/apppasswords
4. Enter an app name (e.g. "Outbox") → Create
5. Copy the 16-character password (e.g. abcd efgh ijkl mnop)
6. Enter it without spaces when prompted

You will be prompted for:

• Gmail address: Your Gmail email address
• App password: The 16-character app password

Outlook (Personal)

For personal accounts (@outlook.com, @hotmail.com, @live.com).

Uses smtp-mail.outlook.com:587 with STARTTLS.

You will be prompted for:

• Email address: Your Outlook email address
• App password: Your app password or account password

Microsoft 365 (Business)

For business/organization Microsoft 365 accounts.

Uses smtp.office365.com:587 with STARTTLS.

You will be prompted for:

• Email address: Your work email address
• App password: Your app password

Naver

Uses smtp.naver.com:587 with STARTTLS.

You will be prompted for:

• Naver ID: Your Naver email address
• Password: Your Naver password or app password

Custom SMTP

For any other SMTP server.

You will be prompted for:

• Host: SMTP server hostname
• Port: SMTP port (default: 587)
• Use TLS: y/n (default: y)
• Username: SMTP username
• Password: SMTP password

KakaoTalk

What it does: Sends messages to yourself via KakaoTalk "Send to Me" API.

Prerequisites:

1. A Kakao account
2. A Kakao Developers application with Messaging API enabled

Setup Steps:

1. Go to developers.kakao.com and log in
2. Go to My Applications → Add Application → Enter app name → Save
3. Go to Product Settings → Kakao Login → Set status to ON
4. Go to Product Settings → Kakao Login → Consent Items
   • Find 카카오톡 메시지 전송 (talk_message) under 접근권한
   • Click 설정 → Select 이용 중 동의 → Enter a purpose (e.g. "AI agent notification") → Save
5. Go to App Settings → Platform Key → Click on your REST API key
   • Copy the REST API Key
   • Under 카카오 로그인 리다이렉트 URI, add: http://localhost:9876/callback
   • Under 클라이언트 시크릿, copy the Client Secret code for 카카오 로그인
   • Ensure 활성화 is set to ON
   • Click 저장

Critical: The redirect URI must be exactly http://localhost:9876/callback — no trailing slash.

Add Channel:

fieldcure-mcp-outbox add kakaotalk

You will be prompted for:

• REST API Key: From step 5
• Client Secret: From step 5 (press Enter to skip if disabled, but new apps have it enabled by default)

After entering credentials:

1. Your browser will automatically open the Kakao login page
2. Log in with your Kakao account and grant permissions
3. The browser will show "Authorization successful!" — you can close it
4. The console will confirm the channel was added

Token Management:

• Access tokens are automatically refreshed when expired
• If the refresh token also expires, send_message will return an error
• Re-run add kakaotalk to re-authorize

CLI Commands

fieldcure-mcp-outbox                      # Start MCP server (stdio)
fieldcure-mcp-outbox add slack            # Add Slack channel
fieldcure-mcp-outbox add telegram         # Add Telegram channel
fieldcure-mcp-outbox add gmail            # Add Gmail SMTP channel
fieldcure-mcp-outbox add outlook          # Add Outlook SMTP channel
fieldcure-mcp-outbox add microsoft365     # Add Microsoft 365 SMTP channel
fieldcure-mcp-outbox add naver            # Add Naver SMTP channel
fieldcure-mcp-outbox add smtp             # Add custom SMTP channel
fieldcure-mcp-outbox add kakaotalk        # Add KakaoTalk channel
fieldcure-mcp-outbox list                 # List configured channels
fieldcure-mcp-outbox remove <id>          # Remove a channel

Data Storage

Project Structure

src/FieldCure.Mcp.Outbox/
├── Program.cs                  # Entry point: MCP server vs CLI branching
├── Channels/
│   ├── IChannel.cs             # Channel interface + SendRequest/SendResult
│   ├── ChannelFactory.cs       # Channel instantiation by type
│   ├── SlackChannel.cs         # Slack Web API
│   ├── TelegramChannel.cs      # WTelegramClient
│   ├── SmtpChannel.cs          # MailKit SMTP
│   └── KakaoTalkChannel.cs     # Kakao REST API
├── Tools/
│   ├── ListChannelsTool.cs     # list_channels
│   ├── AddChannelTool.cs       # add_channel
│   ├── RemoveChannelTool.cs    # remove_channel
│   └── SendMessageTool.cs      # send_message
├── Setup/
│   ├── SetupRunner.cs          # CLI router
│   ├── ConsoleHelper.cs        # Masked input, prompts
│   ├── SlackSetup.cs
│   ├── TelegramSetup.cs
│   ├── SmtpSetup.cs
│   └── KakaoTalkSetup.cs
└── Configuration/
    ├── ChannelStore.cs         # channels.json persistence
    ├── CredentialManager.cs    # Windows Credential Manager wrapper
    └── SmtpPresets.cs          # SMTP preset definitions

Development

# Build
dotnet build

# Test
dotnet test

# Pack as dotnet tool
dotnet pack src/FieldCure.Mcp.Outbox -c Release

License

MIT