┌─────────────────────────────────────────────────────────┐
│                      MCP Server                         │
│                   (cartridge-mcp)                       │
├─────────────────────────────────────────────────────────┤
│  Scene Builder                                          │
│  ┌──────────┐   ┌──────────┐   ┌──────────────────┐    │
│  │Cartridge  │ + │  Skin    │ + │    Roles         │    │
│  │(behavior) │   │(persona) │   │(who does what)   │    │
│  └──────────┘   └──────────┘   └──────────────────┘    │
├─────────────────────────────────────────────────────────┤
│  Cartridge Loader                                       │
│  ┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐              │
│  │Spdr │ │Orcl │ │Grdn │ │ ??? │ │ ??? │  ← swap in   │
│  └─────┘ └─────┘ └─────┘ └─────┘ └─────┘              │
├─────────────────────────────────────────────────────────┤
│  Skin Layer                                             │
│  ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐         │
│  │StrtMn│ │C3PO  │ │R2D2  │ │Rival │ │Field │ ← skins │
│  └──────┘ └──────┘ └──────┘ └──────┘ └──────┘         │
├─────────────────────────────────────────────────────────┤
│  Tool Registry (exposed via MCP)                        │
└─────────────────────────────────────────────────────────┘

# Run as stdio MCP server
node src/server.js

# Or via mcporter
mcporter call --stdio "node src/server.js" cartridge_list

# Custom cartridge directory
CARTRIDGE_DIR=./my-cartridges node src/server.js

{
  "cartridge": "spreader-loop",
  "skin": "sarcastic-build",
  "roles": {
    "primary": "sarcastic-build",
    "reviewer": "straight-man"
  }
}

// cartridges/my-cartridge/cartridge.json
{
  "id": "my-cartridge",
  "name": "My Custom Behavior",
  "version": "0.1.0",
  "description": "What this cartridge does",
  "defaultSkin": "field-journal",
  "repo": "https://github.com/you/my-cartridge",
  "tags": ["custom", "experimental"],
  "onboarding": {
    "human": {
      "greeting": "Welcome to my cartridge.",
      "description": "What it does and why you'd want it.",
      "tools": ["my_tool_1", "my_tool_2"],
      "usage": "How to use it as a human."
    },
    "agent": {
      "greeting": "Cartridge loaded. API ready.",
      "description": "Machine-readable description.",
      "tools": ["my_tool_1", "my_tool_2"],
      "usage": "How another agent should call the tools."
    }
  },
  "tools": [
    {
      "name": "my_tool_1",
      "description": "What this tool does",
      "inputSchema": {
        "type": "object",
        "properties": {
          "param": { "type": "string" }
        },
        "required": ["param"]
      }
    }
  ]
}

// skins/my-skin.json
{
  "id": "my-skin",
  "name": "My Personality",
  "description": "What this personality feels like",
  "archetype": "Comedy / Drama / Professional / Custom",
  "transforms": {
    "default": {
      "systemPrompt": "You are...",
      "prefix": "[mood] ",
      "suffix": ""
    },
    "tool": {
      "prefix": "[tool-mood] ",
      "replacements": {
        "Error": "WHOOPS",
        "Complete": "Nailed it"
      }
    }
  }
}

{
  "prefix": "[confused] Wait, you want me to... ",
  "replacements": {
    "Deploy": "Deploy? Deploy WHAT?",
    "Success": "Oh, that was a deploy? Nobody told ME that was a deploy."
  }
}