MCP Apps Arcade

🚀 Example: Arcade Server

An MCP Apps server enabling users to browse and play classic arcade games from archive.org directly within an MCP - enabled host.

🚀 Quick Start

npm install
npm run dev

The server starts on http://localhost:3002/mcp by default. Set the PORT environment variable to change it.

MCP Client Configuration

{
  "mcpServers": {
    "arcade": {
      "url": "http://localhost:3002/mcp"
    }
  }
}

✨ Features

• Legal Compliance: Only games with verified distribution rights can be loaded. The server uses a strict verification system, including a curated allowlist and metadata verification.
• Game Variety: Offers shareware, freeware, and public - domain games.
• Emulator Support: Utilizes emulators like DOSBox, EM - DOSBox, and MAME from archive.org to run games in the browser.
• CORS Workaround: Temporarily caches archive.org's emulation.min.js script in memory to bypass browser security restrictions.
• Dynamic Game Loading: Allows different games to be displayed based on tool input using the MCP Apps protocol.

📦 Installation

npm install
npm run dev

💻 Usage Examples

Basic Usage

To start the server, run the following commands:

npm install
npm run dev

Advanced Usage

You can change the server port by setting the PORT environment variable. For example:

PORT=3003 npm run dev

📚 Documentation

Legal Disclaimer

This is a technical demonstration, not a distribution platform.

• Games are fetched directly from archive.org's embed system at runtime.
• We do not host, distribute, or store game content.
• Only games with verified distribution rights can be loaded.
• Games without verified rights are blocked.

How Rights Verification Works

The server uses a strict verification system:

1. Curated Allowlist: Games in have externally documented distribution rights with source URLs (publisher announcements, official websites). Each entry includes legal justification.
2. Metadata Verification: For games not in the allowlist, we check archive.org metadata for explicit rights indicators (shareware, freeware, public domain, Creative Commons). Games are only allowed if they have verified rights. Unknown or restricted games are blocked.

What Games Are Available?

• Shareware: First episodes/demos explicitly released for free distribution (DOOM, Duke Nukem, Commander Keen, Wolfenstein 3D, etc.).
• Freeware: Games officially released as free by their publishers (Tyrian 2000, Jill of the Jungle).
• Public Domain: Games with expired or waived copyright. See for the complete list with legal documentation.

Emulator Runtimes

Archive.org uses the Emularity system to run games in the browser. This includes:

Our relationship with these emulators:

• We do not distribute, bundle, or modify any emulator code.
• Emulators are fetched directly from archive.org at runtime.
• We only proxy archive.org's embed system, which hosts its own copies of these emulators.
• The temporary in - memory caching (see below) is purely for CORS workaround purposes.

License compatibility note: The MCP Apps SDK is Apache - 2.0 licensed. There is no license conflict because:

1. The arcade - server does not bundle, include, or link against GPL emulator code.
2. Emulators are fetched from archive.org at runtime (like loading any CDN resource).
3. Emulators execute in the user's browser, a separate execution context.
4. This is analogous to embedding a YouTube video - the embedding page isn't a derivative of YouTube's player. If you create a modified version that bundles emulator code into the distribution, you must comply with GPL - 2.0+ terms (copyleft, source availability).

Script Re - hosting (CORS Workaround)

The server temporarily caches archive.org's emulation.min.js script in memory only (not persisted to disk) to work around browser security restrictions in sandboxed iframes. This is a technical necessity, not redistribution:

• Cache uses Cache - Control: no - store headers.
• Cache is cleared on server restart.
• Script is fetched fresh from archive.org on first request.
• No modifications are made beyond replacing import() with loadScript() for iframe compatibility.

Adding New Games

To add a game to the allowlist, you must provide:

1. sourceUrl: A link to an authoritative source documenting distribution rights (publisher website, press release, official announcement).
2. legalBasis: A clear explanation of why the game is legally distributable.
3. Verification: Confirm the archive.org identifier works. When in doubt, do not add the game.

Overview

This example demonstrates serving external HTML content as an MCP App resource. The resource is a static loader that uses the MCP Apps protocol to receive tool arguments, then fetches the processed game HTML from a server endpoint. This pattern allows the same resource to display different games based on tool input.

Key techniques:

• MCP Apps protocol handshake (ui/initialize → ui/notifications/tool - input) to receive game ID dynamically.
• Server - side HTML fetching and processing per game ID.
• <base href> tag for resolving relative URLs against archive.org.
• baseUriDomains CSP metadata to allow the base tag.
• Rewriting ES module import() to classic <script src> loading (for srcdoc iframe compatibility).
• Local script endpoint to bypass CORS restrictions in sandboxed iframes.
• Rights checking to verify distribution permissions before loading games.

Key Files

• - MCP server with tool and resource registration.
• - HTTP transport and Express setup.
• [game - processor.ts](game - processor.ts) - Fetches and processes archive.org HTML.
• - Archive.org search with smart fallbacks and rights filtering.
• [rights - checker.ts](rights - checker.ts) - Analyzes archive.org metadata for distribution rights.
• - Curated list of verified shareware/freeware games.
• - Type definitions for rights management.

Tools

search_games Parameters

get_game_by_id Parameters

How It Works

1. Host calls search_games → Server searches allowlist + archive.org → Returns verified games only.
2. Host calls get_game_by_id → Server verifies rights status.
3. If rights verified → Tool returns success.
4. If rights NOT verified → Tool returns error, game blocked.
5. Host reads resource → Gets static loader with MCP Apps protocol handler.
6. View performs ui/initialize handshake with host.
7. Host sends tool - input with gameId → View fetches /game - html/:gameId.
8. Server fetches embed HTML from archive.org and processes it:
   - Removes archive.org's <base> tag.
   - Injects <base href="https://archive.org/"> for URL resolution.
   - Rewrites ES module import() to <script src> loading.
   - Fetches emulation.min.js, patches it, serves from local endpoint.
   - Injects layout CSS for full - viewport display.
9. Game runs: emulator loads ROM, initializes MAME, game is playable.

Why the Processing?

Archive.org's game embed pages use ES module import() for loading the emulation engine. In srcdoc iframes (used by MCP hosts), import() fails because the iframe has a null origin. The server works around this by:

1. Fetching emulation.min.js server - side and replacing import() with window.loadScript().
2. Serving the patched script from a local Express endpoint (/scripts/emulation.js).
3. Using <script src> which is not subject to CORS restrictions, unlike fetch() or import().

Available Games (18 Verified Titles)

All games have verified distribution rights. See for legal documentation.

id Software Shareware

Apogee / 3D Realms Shareware

Epic MegaGames Shareware / Freeware