Telegram Relay Rich Markdown

A small, private Model Context Protocol server that lets ChatGPT or another MCP client send Telegram Rich Markdown to one fixed Telegram destination.

The server is intentionally narrow: it exposes one write tool, cannot choose another chat, and does not provide Telegram administration capabilities.

Features

• Sends Telegram Rich Markdown through sendRichMessage.
• Supports headings, lists, task lists, tables, links, quotations, details, spoilers, footnotes, code, and LaTeX formulas.
• Uses one destination configured by TELEGRAM_CHANNEL_ID.
• Protects the MCP endpoint with a high-entropy capability URL.
• Blocks remote media embeds and unsafe URL schemes.
• Suppresses accidental duplicate messages.
• Applies a small best-effort per-instance rate limit.
• Avoids logging message text, bot tokens, destination IDs, or token-bearing Telegram URLs.
• Deploys on Vercel.

Security model

The MCP endpoint is:

https://YOUR-DOMAIN/<MCP_ACCESS_TOKEN>/mcp

Treat the complete URL as a password. This capability-URL approach is suitable for a private, single-user deployment. For a public or multi-user integration, replace it with a standards-based OAuth 2.1 authorization flow.

The tool cannot receive a chat_id; the destination only comes from the server environment. It also does not implement message editing, deletion, member management, webhooks, invite links, paid broadcasts, or other Telegram administration methods.

Remote media blocks are rejected intentionally. Normal text formatting, links, tables, details, quotations, spoilers, footnotes, code, and formulas remain available.

Required environment variables

Variable	Required	Description
TELEGRAM_BOT_TOKEN	Yes	Bot token issued by @BotFather.
TELEGRAM_CHANNEL_ID	Yes	Fixed Telegram destination ID or public channel username.
MCP_ACCESS_TOKEN	Yes	URL-safe random secret with at least 32 characters.
TELEGRAM_PROTECT_CONTENT	No	Defaults to true. Prevents forwarding/saving where Telegram supports it.
TELEGRAM_SKIP_ENTITY_DETECTION	No	Defaults to false.
MCP_MAX_MESSAGES_PER_MINUTE	No	Defaults to 5; accepted range is 1–30.
MCP_DUPLICATE_WINDOW_SECONDS	No	Defaults to 120; accepted range is 0–600.

Generate the MCP access token with:

openssl rand -hex 32

Telegram destination IDs

Use the ID exactly as returned by Telegram:

Destination	Example
Private user chat	123456789
Basic group	-123456789
Supergroup or channel	-1001234567890
Public channel	@examplechannel

For a private bot conversation, first open the bot and send /start. Then retrieve the chat ID:

$updates = Invoke-RestMethod "https://api.telegram.org/bot$token/getUpdates"

$updates.result | ForEach-Object {
  if ($_.message) {
    $_.message.chat
  }
}

Use the returned message.chat.id without modifying it.

Local development

npm install
cp .env.example .env.local
npm run dev

The local endpoint is:

http://localhost:3000/<MCP_ACCESS_TOKEN>/mcp

A non-secret health endpoint is available at:

http://localhost:3000/health

It reports only whether each required setting is present, never its value.

Deploy to Vercel

1. Import this repository into Vercel.
2. Add the required environment variables for Production and Preview.
3. Deploy.
4. Connect your MCP client using:

https://YOUR-PROJECT.vercel.app/<MCP_ACCESS_TOKEN>/mcp

Once the GitHub repository is connected, pushes to main create production deployments and pull requests create preview deployments.

Example Rich Markdown

# Release update

**Version 2.4 is live.**

- Faster imports
- Better error messages
- New analytics table

| Metric | Result |
| --- | ---: |
| Build time | 42 s |
| Tests | 318 passed |

> Deployment completed successfully.

<details>
<summary>Technical notes</summary>

The complexity is $O(n \log n)$.

</details>

Limitations

• The in-memory rate limit and duplicate cache are best-effort because Vercel instances do not share memory.
• Remote images and other remote media embeds are blocked.
• Telegram bots cannot initiate a private conversation until the user has contacted the bot.
• Rich Markdown support depends on the Telegram Bot API version available to the bot.

License

MIT