FieldCure.Mcp.Outbox

FieldCure.Mcp.Outbox

Multi-channel messaging MCP server — send messages through Slack, Telegram, Email (Gmail, Naver, Microsoft Graph API), KakaoTalk, and Discord with a single send_message tool. One install, one interface, multiple channels.

Install

dotnet tool install -g FieldCure.Mcp.Outbox

Quick Start

# Add a Slack channel
fieldcure-mcp-outbox add slack

# Add a Gmail channel
fieldcure-mcp-outbox add gmail

# Start MCP server
fieldcure-mcp-outbox

Claude Desktop

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

Tools (4)

Tool	Description	Confirmation
list_channels	List all configured messaging channels	—
add_channel	Add a new channel (opens setup console)	—
send_message	Send a message through a channel	Required
remove_channel	Remove a channel and its data	Required

Channels

Channel	Protocol	Setup
Slack	Web API (chat.postMessage)	Bot Token
Telegram	Client API (WTelegramClient)	API ID + Hash + SMS
Gmail	SMTP (smtp.gmail.com:587)	App password
Naver	SMTP (smtp.naver.com:465)	App password
Microsoft	Graph API (/me/sendMail)	OAuth 2.0
Custom SMTP	User-defined SMTP server	Username + password
KakaoTalk	Kakao REST API	OAuth 2.0
Discord	Webhook API	Webhook URL

Credential Storage

Credentials are resolved in this order:

• In-memory cache (from prior elicitation or env var pickup in the current session)
• Environment variable OUTBOX_{CHANNEL_ID}_{FIELD} (e.g. OUTBOX_SLACK_GENERAL_BOT_TOKEN)
• channels.json (plaintext, written by the CLI setup flow)
• MCP Elicitation (when the client supports it)

OAuth dynamic tokens (Microsoft, KakaoTalk) are persisted separately in tokens.json with current-user-only file permissions (Windows ACL / Unix 0600). Channel setup never passes credentials through MCP stdio.

Plaintext storage in channels.json is a deliberate local-trust choice — same same-user security boundary as ~/.docker/config.json and ~/.config/gh/hosts.yml. For shared hosts, CI, or headless deployments, set the env vars directly and leave the secret fields of channels.json empty. See ADR-001 Principle 2.

Requirements

• .NET 8.0 Runtime or later

See Also

Part of the AssistStudio ecosystem.

• GitHub
• MCP Specification