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GB Studio MCP Server

Create and modify GB Studio projects with MCP tools for scenes, actors, assets, and validation.

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Jan 28, 2026
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Quick Install

npx -y gbstudio-claude-mcp

GB Studio Agentic MCP Server for creating GameBoy Games.

Prompt to build out a template for your students kids or self to extend. Screenshot_20260128-214729 WhatsApp image

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Pong (Game Boy)

Create a Pong clone for the original Game Boy. Two paddles, a ball, and a score counter. The player controls the left paddle, the right paddle is AI-controlled. Use simple monochrome graphics and authentic GB sound effects. Generate all scenes, actors, and assets for a playable Pong game.

Pac-Man (Game Boy Color)

Build a Pac-Man style maze game for Game Boy Color. The player navigates a maze, collects pellets, and avoids ghosts. Include at least one maze layout, four ghosts with basic AI, and colorful graphics. Generate all scenes, actors, and assets needed for a playable demo.

Mario Bros Style Platformer (Game Boy Color)

Design a Mario Bros inspired platformer for Game Boy Color. The player can run, jump, and stomp on enemies. Include three levels, power-ups, coins, and a flagpole at the end of each level. Use bright palettes and catchy background music. Generate all scenes, actors, and assets for a classic platformer experience.

Space Shooter (Game Boy)

Create a vertical scrolling space shooter for the original Game Boy. The player controls a spaceship, shoots enemies, and dodges obstacles. Include multiple enemy types, power-ups, and a boss fight. Use classic GB graphics and chiptune sound effects. Generate all scenes, actors, and assets for a playable shooter.

Claude MCP Server for GB Studio

This is a TypeScript server for manipulating GB Studio projects using the Model Context Protocol (MCP). It provides endpoints for project discovery, validation, and creation of game assets.

Installation

Install globally with npm:

npm install -g gbstudio-claude-mcp

Local Environment Setup (.env)

For local development, store API keys and configuration in a .env file at the project root. This keeps secrets out of source control and matches the pattern used in GitHub Actions.

  1. Create a .env file in the project root: 
    CLAUDE_API_KEY=your-claude-api-key-here
# Add other keys as needed
  2. The server will automatically load variables from .env if you use [dotenv].
  3. .env files are gitignored by default.

Never commit your .env file to source control.

Usage

Start the server:

gbstudio-claude-mcp

The server runs on http://localhost:3000 by default.

Configure your MCP client (e.g., Claude Desktop) to connect to this server. For full setup and troubleshooting, see the tutorial linked at the end of this document.

End-to-End Usage: Windows & Linux/macOS

See the TUTORIAL.md for a complete, step-by-step guide to building a GB Studio game with this server, including screenshots and troubleshooting tips for both Windows and Linux/macOS.

MCP Protocol Support

This package supports the Model Context Protocol (MCP). You can run the server in MCP stdio mode for use with Claude Desktop and other MCP clients:

npm run build:mcp
node build/mcp.js

The MCP stdio server proxies to the local REST API on http://localhost:3000, so start the REST server first. To use a different port, set GBSTUDIO_API_URL (full URL) or GBSTUDIO_API_PORT (port number):

gbstudio-claude-mcp

Or add this to your MCP client configuration:

{
   "mcpServers": {
      "gbstudio-mcp": {
         "command": "node",
         "args": ["/absolute/path/to/build/mcp.js"]
      }
   }
}

Clawdbot / Moltbot Compatibility

Clawdbot and Moltbot discover tools via AgentSkills-compatible SKILL.md files. This repo ships one at:

  • skills/gbstudio-mcp/SKILL.md

Compatibility depends on transport:

  • If Clawdbot can run stdio MCP servers as child processes, node build/mcp.js will work.
  • If your Clawdbot setup expects HTTP+SSE MCP servers, you will need a bridge, because this MCP server is stdio-only.
  • If you only run the REST API, Clawdbot will not auto-discover tools as MCP.

To enable the skill in Moltbot, add an entry like this:

{
  "skills": {
    "load": {
      "extraDirs": [
        "~/.clawdbot/skills"
      ],
      "watch": true,
      "watchDebounceMs": 250
    },
    "entries": {
      "gbstudio-mcp": {
        "enabled": true,
        "env": {}
      }
    }
  }
}

Project Structure

  • src/index.ts — Main server and endpoint logic
  • tests/ — Jest test suites for all endpoints
  • tests/poachermon/ — Real GB Studio project for integration tests
  • gbstudio_api_endpoints.csv — Catalog of all planned endpoints

Local Development

  1. Clone the repository: 
    git clone https://github.com/eoinjordan/gb-studio-agent.git
cd gb-studio-agent
  2. Install Node.js (recommended: v21.7.1 or compatible)
  3. Install dependencies: 
    npm install
  4. Start the development server: 
    npm run dev
  5. Run the test suite: 
    npm test

Health

  • GET /health — Returns { status: "ok" } for health checks.

Claude API Key

  • GET /claude-key — Returns { present: true } if CLAUDE_API_KEY is set in the environment, else { present: false } with 404.

Find Project

  • POST /find_project — Finds the first .gbsproj file starting from a given directory.
    • Body: { startPath: string }
    • Returns: { projectPath: string } or 404 if not found.

Inventory

  • POST /inventory — Lists scenes, actors, triggers, and assets from a GB Studio project root.
    • Body: { projectRoot: string }
    • Returns: { scenes, actors, triggers, assets } or 404/400 on error.

Validate

  • POST /validate — Validates the structure of a GB Studio project (checks for a valid .gbsproj file and required fields).
    • Body: { projectRoot: string }
    • Returns: { valid: true, message: string, scenes: number } if valid, or 400/404 with an error message if invalid or missing required fields.
    • Error Cases:
      • 400 if projectRoot is missing or .gbsproj is invalid/missing required fields
      • 404 if projectRoot does not exist or no .gbsproj file found

Create Scene

  • POST /scene/create — Adds a new scene to the specified GB Studio project.
    • Body: { projectRoot: string, scene: object }
    • Returns: { success: true, scene } on success, or 400/404/500 with an error message.

Create Actor

  • POST /actor/create — Creates a new actor in the specified scene.
    • Body: { projectRoot: string, sceneId: string, actor: object }
    • Returns: { success: true, actor } on success, or 400/404/500 with an error message.

Create Background

  • POST /background/create — Creates a new background in the project.
    • Body: { projectRoot: string, background: object }
    • Returns: { success: true, background } on success, or 400/404/500 with an error message.

Create Sprite

  • POST /sprite/create — Creates a new sprite in the project.
    • Body: { projectRoot: string, sprite: object }
    • Returns: { success: true, sprite } on success, or 400/404/500 with an error message.

Create Music

  • POST /music/create — Creates a new music track in the project.
    • Body: { projectRoot: string, music: object }
    • Returns: { success: true, music } on success, or 400/404/500 with an error message.

Create Sound

  • POST /sound/create — Creates a new sound effect in the project.
    • Body: { projectRoot: string, sound: object }
    • Returns: { success: true, sound } on success, or 400/404/500 with an error message.

Create Tileset

  • POST /tileset/create — Creates a new tileset in the project.
    • Body: { projectRoot: string, tileset: object }
    • Returns: { success: true, tileset } on success, or 400/404/500 with an error message.

Create Trigger

  • POST /trigger/create — Creates a new trigger in the specified scene.
    • Body: { projectRoot: string, sceneId: string, trigger: object }
    • Returns: { success: true, trigger } on success, or 400/404/500 with an error message.

Create Variable

  • POST /variable/create — Creates a new variable in the project.
    • Body: { projectRoot: string, variable: object }
    • Returns: { success: true, variable } on success, or 400/404/500 with an error message.

Create Script

  • POST /script/create — Creates a new script in the project.
    • Body: { projectRoot: string, script: object }
    • Returns: { success: true, script } on success, or 400/404/500 with an error message.

Create Palette

  • POST /palette/create — Creates a new palette in the project.
    • Body: { projectRoot: string, palette: object }
    • Returns: { success: true, palette } on success, or 400/404/500 with an error message.

Create Font

  • POST /font/create — Creates a new font in the project.
    • Body: { projectRoot: string, font: object }
    • Returns: { success: true, font } on success, or 400/404/500 with an error message.

Create Emote

  • POST /emote/create — Creates a new emote in the project.
    • Body: { projectRoot: string, emote: object }
    • Returns: { success: true, emote } on success, or 400/404/500 with an error message.

Create Avatar

  • POST /avatar/create — Creates a new avatar in the project.
    • Body: { projectRoot: string, avatar: object }
    • Returns: { success: true, avatar } on success, or 400/404/500 with an error message.

Create Constant

  • POST /constant/create — Creates a new constant in the project.
    • Body: { projectRoot: string, constant: object }
    • Returns: { success: true, constant } on success, or 400/404/500 with an error message.

Create Prefab Actor

  • POST /prefab/actor/create — Creates a new actor prefab in the project.
    • Body: { projectRoot: string, actorPrefab: object }
    • Returns: { success: true, actorPrefab } on success, or 400/404/500 with an error message.

Create Prefab Trigger

  • POST /prefab/trigger/create — Creates a new trigger prefab in the project.
    • Body: { projectRoot: string, triggerPrefab: object }
    • Returns: { success: true, triggerPrefab } on success, or 400/404/500 with an error message.

Update Settings

  • POST /settings/update — Updates project settings.
    • Body: { projectRoot: string, settings: object }
    • Returns: { success: true, settings } on success, or 400/404/500 with an error message.

Update Metadata

  • POST /metadata/update — Updates project metadata.
    • Body: { projectRoot: string, metadata: object }
    • Returns: { success: true, metadata } on success, or 400/404/500 with an error message.

Create Engine Field Value

  • POST /engine-field-value/create — Creates a new engine field value in the project.
    • Body: { projectRoot: string, engineFieldValue: object }
    • Returns: { success: true, engineFieldValue } on success, or 400/404/500 with an error message.

Claude Key

  • POST /claude/key — Sets the Claude API key in the environment.
    • Body: { key: string }
    • Returns: { success: true } on success, or 400 with an error message.

Building a Game End-to-End

To build a GB Studio game using this MCP server with Claude:

  1. Discover Project: Use /find_project to locate an existing .gbsproj file or start from a directory.
  2. Validate Project: Use /validate to ensure the project is valid.
  3. Get Inventory: Use /inventory to list current scenes, actors, triggers, assets.
  4. Create Scenes: Use /scene/create to add new scenes.
  5. Create Actors: Use /actor/create to add actors to scenes.
  6. Create Assets: Use creation endpoints (currently stubs) to add sprites, backgrounds, etc.
  7. Update Settings/Metadata: Use update endpoints to configure the project.
  8. Build/Export: (Future) Use build endpoint to compile the game.

Note: All endpoints are now fully functional.

Example Prompts

See TUTORIAL.md for detailed sample prompts and full end-to-end workflows for different game genres.

Test Coverage

All endpoints are covered by Jest tests in the tests/ directory. Run npm test to validate all functionality. Tests use real sample projects.

Publishing

To publish a new version:

  1. Update version in package.json
  2. Build the project: 
    npm run build
  3. Login to npm: 
    npm login --auth-type=legacy
  4. Publish to npm: 
    npm publish --access public

See npm publishing docs for more info.

Contributing

  1. Fork the repository
  2. Create a feature branch
  3. Make changes and add tests
  4. Submit a pull request to https://github.com/eoinjordan/gb-studio-agent

License

MIT

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