Outbox

Name: Outbox
Author: fieldcure

by fieldcureversion 2.1.3i★ 0iRuns on your computer

Registry nameio.github.fieldcure/outbox

How to install

What it does

Multi-channel messaging MCP server for Slack, Telegram, Email, KakaoTalk, and Discord.

Connects Runs on your computer
Account or key No key needed
Category Chat & email

Install

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

Passed 3/3 checks · Runs on your computer · ✓ Commands checked Nov 14, 2026

First: which AI do you use?

ClaudeWeb · app · phoneChatGPTWebClaude CodeTerminalCursorCode editorVS CodeCode editorOtherOther apps

Pick your app and the steps appear below.

Works with Claude, with some setup first

No key, nothing to install · Only the Claude desktop app (Windows or Mac), not the web or phone

Let AI install it

Copy this message into a Claude chat. The AI checks your computer, tells you which file it will change, and waits for your OK every time.

Please install the MCP server Outbox for Claude on this computer, in this order: 1) 2) Use only this config (already checked by PopNx MCP): { "mcpServers": { "outbox": { "command": "dnx", "args": [ "FieldCure.Mcp.Outbox", "--yes" ] } } } 3) Tell me the full path of the file you will change, or the command you will run, and wait for my OK. 4) No key is needed. 5) Do what we agreed, then check that the Outbox tools really show up.

This message has no key in it. If a key is needed, the AI will ask you to paste it yourself into the file or the app’s field.

Open the Claude desktop app’s settings file
SettingsDeveloperEdit Config
Done

Paste these settings and save the file

{
  "mcpServers": {
    "outbox": {
      "command": "dnx",
      "args": [
        "FieldCure.Mcp.Outbox",
        "--yes"
      ]
    }
  }
}

Done

Quit Claude and open it again
Done
Try it
Use Outbox and tell me what you can do for me, then show me one thing
✓ If Claude says it is using Outbox or shows a Outbox tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

ChatGPT cannot connect Outbox yet

Outbox runs on your computer, but ChatGPT can only connect servers that run on the web

What you can do instead

A · Use an app that can connect Outbox

Steps for Claude →No key, nothing to install · Only the Claude desktop app (Windows or Mac), not the web or phone
Steps for Claude Code →No key, nothing to install
Steps for Cursor →No key, nothing to install
Steps for VS Code →No key, nothing to install

B · Others in Chat & email that work with ChatGPT

Picked from the most used in the same category, only ones that connect by address with no key

HyperFrames by HeyGen✓ ChatGPT
Inbox Zero✓ ChatGPT
emailmd✓ ChatGPT

Works with Claude Code, with some setup first

No key, nothing to install

Let AI install it

Copy this message into a Claude Code chat. The AI checks your computer, tells you which file it will change, and waits for your OK every time.

Please install the MCP server Outbox for Claude Code on this computer, in this order: 1) 2) Use only this config (already checked by PopNx MCP): claude mcp add --scope user outbox -- dnx FieldCure.Mcp.Outbox --yes 3) Tell me the full path of the file you will change, or the command you will run, and wait for my OK. 4) No key is needed. 5) Do what we agreed, then check that the Outbox tools really show up.

This message has no key in it. If a key is needed, the AI will ask you to paste it yourself into the file or the app’s field.

Open Terminal
Mac: press Command+Space and type Terminal · Windows: open PowerShell
Done

Paste this command and press Enter

claude mcp add --scope user outbox -- dnx FieldCure.Mcp.Outbox --yes

Done

Type /mcp in Claude Code
You should see Outbox listed as connected
Done
Try it
Use Outbox and tell me what you can do for me, then show me one thing
✓ If Claude Code says it is using Outbox or shows a Outbox tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with Cursor, with some setup first

No key, nothing to install

Let AI install it

Copy this message into a Cursor chat. The AI checks your computer, tells you which file it will change, and waits for your OK every time.

Please install the MCP server Outbox for Cursor on this computer, in this order: 1) 2) Use only this config (already checked by PopNx MCP): { "mcpServers": { "outbox": { "command": "dnx", "args": [ "FieldCure.Mcp.Outbox", "--yes" ] } } } 3) Tell me the full path of the file you will change, or the command you will run, and wait for my OK. 4) No key is needed. 5) Do what we agreed, then check that the Outbox tools really show up.

This message has no key in it. If a key is needed, the AI will ask you to paste it yourself into the file or the app’s field.

Click this button to open Cursor
Open in Cursor
Cursor asks you to confirm; click Install
Done
Open the AI chat in Cursor in Agent mode
Done
Try it
Use Outbox and tell me what you can do for me, then show me one thing
✓ If Cursor says it is using Outbox or shows a Outbox tool in the answer, you are connected

Menu names checked against Cursor’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with VS Code, with some setup first

No key, nothing to install

Let AI install it

Copy this message into a VS Code chat. The AI checks your computer, tells you which file it will change, and waits for your OK every time.

Please install the MCP server Outbox for VS Code on this computer, in this order: 1) 2) Use only this config (already checked by PopNx MCP): { "servers": { "outbox": { "type": "stdio", "command": "dnx", "args": [ "FieldCure.Mcp.Outbox", "--yes" ] } } } 3) Tell me the full path of the file you will change, or the command you will run, and wait for my OK. 4) No key is needed. 5) Do what we agreed, then check that the Outbox tools really show up.

This message has no key in it. If a key is needed, the AI will ask you to paste it yourself into the file or the app’s field.

Click this button to open VS Code
Open in VS Code
VS Code asks you to confirm; click Install
Done
Open the AI chat in VS Code in Agent mode
Done
Try it
Use Outbox and tell me what you can do for me, then show me one thing
✓ If VS Code says it is using Outbox or shows a Outbox tool in the answer, you are connected

Menu names checked against VS Code’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Other apps that use MCP, such as Windsurf, Zed or Gemini CLI, each add servers differently. See how in the app list.

See every app that uses MCP →

JSON settings are under “For developers” below

Stuck? Ask people who use Outbox💬 Discussion →

For developers: Terminal commands and JSON settings

Installed on your computer

Claude Code

claude mcp add --scope user outbox -- dnx FieldCure.Mcp.Outbox --yes

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "outbox": {
      "command": "dnx",
      "args": [
        "FieldCure.Mcp.Outbox",
        "--yes"
      ]
    }
  }
}

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "outbox": {
      "command": "dnx",
      "args": [
        "FieldCure.Mcp.Outbox",
        "--yes"
      ]
    }
  }
}

VS Code (mcp.json)

{
  "servers": {
    "outbox": {
      "type": "stdio",
      "command": "dnx",
      "args": [
        "FieldCure.Mcp.Outbox",
        "--yes"
      ]
    }
  }
}

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

At a glance

GitHub stars i: 0
Downloads per weeki: Not on npm/PyPI
Licence i: MIT
Connection: Runs on your computer
Transport: stdio
Latest versioni: 2.1.3
Categoryi: Chat & email
Published to registryi: May 25, 2026
Code last changedi: May 25, 2026
Maker: fieldcure
Packages: nuget: FieldCure.Mcp.Outbox
Repo: fieldcure/fieldcure-mcp-outbox
Registry status: Active

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Run on your computer in

Claude Goose LM Studio Msty Studio Cherry Studio Cursor VS Code + GitHub Copilot Visual Studio Windsurf (Devin Desktop)Zed Kiro Cline Continue JetBrains AI Assistant Claude Code Codex CLI Gemini CLI OpenCode nodecode Warp LibreChat Raycast

All apps, with pros and cons →

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 15, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account fieldcure, which owns the repo
✓ Pass
Still maintained
Code last changed 6 months ago
✓ Pass
Has a licence
Uses MIT
– 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

Published vulnerabilities (OSV.dev)

Not checked: only npm and PyPI packages with a version can be checked

What we check → · JSON

Makers: ask for a re-check or report wrong info

Discussion

Ask, share a tip or report that it does not work. Sorted by what people marked helpful.

No posts yet. Be the first to ask or share.

Posts here are written by users, not the PopNx team.

User reviews

No reviews yet

Compared with others in Chat & emaili

More stars than 0% of the other 2049 servers in this category
Published to the registry more recently than 9% of the other 2049 servers in this category
Basic checks equal to or better than 100% of the other 2049 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 Outbox safe?

It passed 3 of 3 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?

The registry does not list a required key, though some servers ask you to sign in on first use.

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 6 months ago, and the latest version (2.1.3) reached the registry 6 months ago.

Which apps can use it?

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

What can I use instead?

In the same category: draw.io, Vexa, emailmd, Kite Discord Bot Builder, e2a — email for AI agents

Similar alternatives

Same category, other makers, commands already checked. Official ones first, then by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

draw.io

Create draw.io diagrams in chat from Mermaid or XML, shown live and interactive. 10,000+ shapes.

by jgraphWidely used★ 5.8KUpdated 5 days ago

Runs in the cloud✓ service owner · draw.ioTried by the PopNx team

How to connect

Vexa

Meeting bot and transcripts for Google Meet, Teams and Zoom. Live or after, speakers labelled.

by Vexa-aiWidely used★ 3KUpdated 2 months ago

Runs in the cloud✓ service owner · vexa.ai

How to connect

emailmd

Render markdown into email-safe HTML, lint drafts for deliverability problems, and preview emails.

by anypostWidely used↓ 5.4K/wk★ 1.4KUpdated yesterday

Computer or cloud✓ service owner · emailmd.dev

Install

Kite Discord Bot Builder

Build and fix Discord bots from a chat. Kite hosts them 24/7, with no code to deploy.

by merlinfuchsGrowing★ 334 Stars for the whole repoUpdated 18 days ago

Runs in the cloud✓ service owner · kite.onl

How to connect

e2a — email for AI agents

Authenticated email gateway for AI agents — per-agent inboxes, HITL approval, SPF/DKIM verified.

by tokencanopyGrowing★ 199 Stars for the whole repoUpdated 4 months ago

Runs in the cloud✓ service owner · e2a.dev

How to connect

draw.io — Runs in the cloud, nothing to install · No key needed
Vexa — Runs in the cloud, nothing to install · Needs a key
emailmd — Cloud or install on your computer · No key needed
Kite Discord Bot Builder — Runs in the cloud, nothing to install · No key needed
e2a — email for AI agents — Runs in the cloud, nothing to install · No key needed

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.

FieldCure MCP Outbox Server

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

Features

Multiple messaging channels — Slack, Telegram, Email (Gmail, Naver, Microsoft Graph API), KakaoTalk, Discord
4 MCP tools — list_channels, add_channel, send_message, remove_channel
Cross-platform credential flow — runtime secrets can come from env vars or MCP elicitation; OAuth tokens are stored separately for refresh lifecycle
CLI channel setup — interactive console for browser/OAuth flows where applicable
SMTP presets — Gmail, Naver with one-command setup
Microsoft Graph API — OAuth 2.0 browser flow for Outlook / M365 email with automatic token refresh
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

Why Outbox?

Existing MCP servers are channel-specific — one for Slack, another for Gmail, yet another for Telegram. Each requires separate installation, configuration, and the LLM must know which tool to call for each channel.

Outbox takes a different approach:

One tool, multiple channels — send_message abstracts away channel differences. The LLM doesn't need to know Slack API vs SMTP vs Kakao REST.
Credential isolation — OAuth refresh tokens live in tokens.json with current-user-only file permissions; MCP tool flows can resolve secrets at runtime via env vars or elicitation.
Single install — dotnet tool install -g gives you 4 channels. No need to install and configure separate servers per channel.
KakaoTalk support — Currently the only MCP server with KakaoTalk messaging, essential for Korean users.

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
Cross-platform (Windows, Linux, macOS)

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

Tool	Description	Confirmation
`list_channels`	List all configured messaging channels	—
`add_channel`	Add a new channel (MCP elicitation for all channel types; Microsoft/KakaoTalk require a local browser on the MCP host)	—
`send_message`	Send a message through a configured channel	Required
`remove_channel`	Remove a channel and its stored credentials	Required

Channels

OAuth tokens for Microsoft/KakaoTalk are stored in tokens.json so the server can refresh them across runs (current-user-only file permissions — Windows ACL / Unix 0600).

Static secrets (Slack bot tokens, Discord webhook URLs, SMTP passwords, etc.) resolve at send time in this order: in-memory cache → env var OUTBOX_{CHANNEL_ID}_{FIELD} → plaintext in channels.json → MCP elicitation. The CLI add_channel flow writes directly into channels.json for a zero-configuration local experience. This is an intentional local-trust choice with the same same-user boundary as tokens.json, documented in ADR-001 Principle 2. For shared hosts, CI, or headless deployments, set the env vars explicitly and leave channels.json secret fields empty.

Channel	Protocol	Setup
Slack	Web API (`chat.postMessage`)	Guide
Telegram	Client API (WTelegramClient)	Guide
Gmail	SMTP	Guide
Naver	SMTP	Guide
Microsoft	Graph API (`/me/sendMail`)	Guide
KakaoTalk	Kakao REST API	Guide
Discord	Webhook API	Guide
Custom SMTP	User-defined	Guide

Static Secret Environment Variables

When a channel requires a static secret at send time, Outbox looks for an environment variable named:

OUTBOX_<CHANNEL_ID>_<FIELD>

Examples:

OUTBOX_MICROSOFT_1_CLIENT_SECRET
OUTBOX_KAKAOTALK_1_API_KEY
OUTBOX_KAKAOTALK_1_CLIENT_SECRET
OUTBOX_SMTP_GMAIL_1_PASSWORD

If the variable is unset and the MCP client supports elicitation, Outbox prompts for it interactively and caches it for the current session.

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 naver # Add Naver SMTP channel fieldcure-mcp-outbox add smtp # Add custom SMTP channel fieldcure-mcp-outbox add microsoft # Add Microsoft (Outlook/M365) channel fieldcure-mcp-outbox add kakaotalk # Add KakaoTalk channel fieldcure-mcp-outbox add discord # Add Discord channel fieldcure-mcp-outbox list # List configured channels fieldcure-mcp-outbox remove # Remove a channel

Data Storage

Data	Location
Channel metadata	`%LOCALAPPDATA%\FieldCure\Mcp.Outbox\channels.json`
OAuth tokens	`%LOCALAPPDATA%\FieldCure\Mcp.Outbox\tokens.json`
Telegram sessions	`%LOCALAPPDATA%\FieldCure\Mcp.Outbox\sessions\`

tokens.json is stored in plain JSON and protected by filesystem permissions:

Windows: ACL restricted to the current user
Linux/macOS: mode 0600

This protects against other local users on the same machine, but not against compromise of the same OS user account.

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 │ ├── MicrosoftChannel.cs # Microsoft Graph API │ ├── KakaoTalkChannel.cs # Kakao REST API │ └── DiscordChannel.cs # Discord Webhook API ├── Tools/ │ ├── ListChannelsTool.cs # list_channels │ ├── AddChannelTool.cs # add_channel (elicitation + browser OAuth for Kakao/Microsoft) │ ├── RemoveChannelTool.cs # remove_channel │ └── SendMessageTool.cs # send_message ├── Interaction/ │ ├── IElicitGate.cs # Minimal MCP elicitation surface for tests │ └── McpServerElicitGate.cs # Production adapter around McpServer ├── OAuth/ │ └── BrowserOAuthFlow.cs # Localhost callback + Process.Start + elicit race (MCP and CLI entry points) ├── Credentials/ │ └── OutboxSecretResolver.cs # cache → env → channels.json → elicitation ├── Setup/ │ ├── SetupRunner.cs # CLI router (diagnostic path) │ ├── ConsoleHelper.cs # Masked input, prompts │ ├── SlackSetup.cs │ ├── TelegramSetup.cs │ ├── SmtpSetup.cs │ ├── MicrosoftSetup.cs │ ├── KakaoTalkSetup.cs │ └── DiscordSetup.cs └── Configuration/ ├── ChannelStore.cs # channels.json persistence (metadata + static-secret fallback) ├── OAuthTokenStore.cs # tokens.json persistence (OAuth access/refresh, user-only file perms) └── 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

Outbox

What it does

Install

Open the Claude desktop app’s settings file

Paste these settings and save the file

Quit Claude and open it again

Try it

What you can do instead

Open Terminal

Paste this command and press Enter

Type /mcp in Claude Code

Try it

Click this button to open Cursor

Open the AI chat in Cursor in Agent mode

Try it

Click this button to open VS Code

Open the AI chat in VS Code in Agent mode

Try it

Installed on your computer

At a glance

Which apps can use it

Related guides

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

Published vulnerabilities (OSV.dev)

Discussion

User reviews

Compared with others in Chat & emaili

Common questions

Similar alternatives

draw.io

Vexa

emailmd

Kite Discord Bot Builder

e2a — email for AI agents

README from the maker

FieldCure MCP Outbox Server

Features

Why Outbox?

Installation

dotnet tool (recommended)

From source

Requirements

Configuration

Claude Desktop

VS Code (Copilot)

From source (without dotnet tool)

Tools

Channels

Static Secret Environment Variables

CLI Commands

Data Storage

Project Structure

Development

Test

Pack as dotnet tool

See Also

License