app.json

{
    "name": "Heroku MCP Server - Node Code Execution",
    "description": "Model Context Protocol server to run Node code.",
    "repository": "https://github.com/heroku-reference-apps/mcp-code-exec-node",
    "env": {
        "API_KEY": {
            "description": "API key for authentication",
            "required": true,
            "generator": "secret"
        },
        "WEB_CONCURRENCY": {
            "description": "Number of Uvicorn worker processes to launch (leave at 1 for async SSE server)",
            "value": "1"
        },
        "STDIO_MODE_ONLY": {
            "description": "Only allow tool requests via STDIO mode?",
            "value": "false"
        },
        "REMOTE_SERVER_TRANSPORT_MODULE": {
            "description": "Tranport module name used for deployed web app (applicable when web formation size is >0). `streamable_http_server` or `sse_server`.",
            "value": "streamable_http_server"
        },
        "USE_TEMP_DIR": {
           "description": "Use a temporary working directory for npm installs and code execution. Not a secure sandbox.",
            "value": "false"
        }
    },
    "formation": [
        {
            "quantity": 0,
            "size": "standard-1x",
            "type": "web"
        }
    ],
    "addons": [],
    "buildpacks": [
        {
            "url": "heroku/python"
        },
        {
            "url": "heroku/nodejs"
        }
    ]
}