Summer Engine CLI

CLI and MCP tools for Summer Engine — the AI-native game engine.

Install

npm install -g summer-engine

Or use without installing:

npx summer-engine <command>

Commands

| Command | Description | |---------|-------------| | summer install | Download and install Summer Engine | | summer login | Sign in via browser (Google/GitHub) | | summer logout | Clear auth tokens | | summer status | Check engine status, port, auth state | | summer run [path] | Launch engine (optionally with a project) | | summer open <path> | Open a project in the running engine | | summer create <template> [name] | Create new project from template | | summer list templates | Show available templates | | summer list projects | Show local projects | | summer skills list | Show available skills (best-practice guides) | | summer skills install <name> | Install a skill for AI agents to use | | summer mcp | Start MCP server (used by Cursor/Claude Code) |

Quick Start

summer install          # Download the engine
summer login            # Sign in
summer create 3d-basic my-game   # Create a project
summer run my-game      # Open it in the engine

MCP Integration

Use Summer Engine with Cursor, Claude Code, or any MCP-compatible AI tool.

Cursor (.cursor/mcp.json):

{
  "mcpServers": {
    "summer-engine": {
      "command": "npx",
      "args": ["summer-engine", "mcp"]
    }
  }
}

Claude Code (~/.claude/claude_code_config.json):

{
  "mcpServers": {
    "summer-engine": {
      "command": "npx",
      "args": ["summer-engine", "mcp"]
    }
  }
}

The MCP server exposes 24 focused tools for scene manipulation, debugging, project settings, and asset search — only things AI tools can't do on their own.

Visual feedback (viewport and game screenshots) is currently available in the Summer Engine app via the built-in Summer Agent. MCP support for screenshots is in development.

How It Works

1. Summer Engine runs a local API server on localhost:6550
2. The MCP server connects to this API via a local auth token (~/.summer/api-token)
3. AI tools call MCP tools, which translate to API requests to the engine
4. The engine executes operations and returns results

The engine must be running for MCP tools to work. If it's not running, tools return a helpful error message.

Templates

Built-in templates:

• empty — Empty 3D project with a root node
• 3d-basic — 3D scene with camera, light, and floor

More templates coming soon.

Links

• Website
• Documentation
• Community