html-cloud-mcp

An MCP server that lets Claude and other AI assistants share the HTML they generate as a private, end-to-end encrypted link — no account, no public URL.

The assistant calls one tool, share_html. The HTML is encrypted locally with AES-256-GCM before anything is uploaded; html.cloud stores only ciphertext and cannot read it.

"Make me a one-page summary of this and share it privately." → the assistant generates the HTML, calls share_html, and replies with a link.

Install

Add it to your MCP client. For Claude Desktop, in claude_desktop_config.json:

{
  "mcpServers": {
    "html-cloud": {
      "command": "npx",
      "args": ["-y", "html-cloud-mcp"]
    }
  }
}

For Claude Code:

claude mcp add html-cloud -- npx -y html-cloud-mcp

Requires Node.js 20+.

The tool

share_html

| Argument | Type | Description | |---|---|---| | html | string (required) | The full, self-contained HTML document to share. | | expires | 7 | 30 | never | Days until the link expires. Default 30. |

Returns a share link (give it to anyone you want to read the file) and a private edit link (replace the file, change the expiry, or delete it).

How the encryption works

• Keys are generated inside this server process and never sent anywhere except inside the links it returns.
• The HTML is encrypted with AES-256-GCM before any network request. Only ciphertext is uploaded.
• The decryption key sits after the # in the share link — that part of a URL is never transmitted to a server.

This is the same zero-knowledge model as the html.cloud website and CLI, using the same crypto module (imported from the html-cloud package — never reimplemented). Full explainer: html.cloud/security.

Configuration

| Env var | Description | Default | |---|---|---| | HTML_CLOUD_URL | Server base URL (for self-hosted instances) | https://html.cloud |

Honest threat model

Anyone with the share link can read the file — the link is the credential. The server can expire or delete ciphertext but can never read it. See html.cloud/security for details and limitations.

Source: github.com/viljamilaurila/html-cloud · MIT