Demo 17: MCP Lazy Loading

{
  "meta": {
    "title": "MCP Lazy Loading",
    "description": "Scale to 100+ MCP servers with on-demand tool schema loading, LRU caching, and context savings.",
    "duration_seconds": 360,
    "version": "1.0.0"
  },
  "steps": [
    {
      "id": 1,
      "action": "write_file",
      "path": "~/.vibecli/config.toml",
      "content": "[mcp]\nenabled = true\nlazy_loading = true\n\n[mcp.lazy]\ncache_size = 50\neviction_policy = \"lru\"\nschema_ttl = 3600\nmetrics_enabled = true\n\n[mcp.servers.filesystem]\ncommand = \"npx\"\nargs = [\"-y\", \"@modelcontextprotocol/server-filesystem\", \"/tmp/demo\"]\n\n[mcp.servers.github]\ncommand = \"npx\"\nargs = [\"-y\", \"@modelcontextprotocol/server-github\"]\nenv = { GITHUB_TOKEN = \"ghp_demo\" }\n\n[mcp.servers.slack]\ncommand = \"npx\"\nargs = [\"-y\", \"@modelcontextprotocol/server-slack\"]\nenv = { SLACK_BOT_TOKEN = \"xoxb-demo\" }\n\n[mcp.servers.postgres]\ncommand = \"npx\"\nargs = [\"-y\", \"@modelcontextprotocol/server-postgres\", \"postgresql://localhost/demo\"]\n\n[mcp.servers.memory]\ncommand = \"npx\"\nargs = [\"-y\", \"@modelcontextprotocol/server-memory\"]\n",
      "description": "Configure lazy loading with 5 MCP servers",
      "delay_ms": 1000
    },
    {
      "id": 2,
      "action": "repl",
      "commands": [
        { "input": "/mcp list", "delay_ms": 3000 }
      ],
      "description": "List all configured servers and verify connections"
    },
    {
      "id": 3,
      "action": "repl",
      "commands": [
        { "input": "/mcp tools", "delay_ms": 3000 }
      ],
      "description": "View the lightweight tool registry (no full schemas loaded yet)"
    },
    {
      "id": 4,
      "action": "Narrate",
      "value": "Notice that only tool names and one-line descriptions are shown. Zero full schemas are in memory -- this is lazy loading in action."
    },
    {
      "id": 5,
      "action": "repl",
      "commands": [
        { "input": "/mcp search \"send a message\"", "delay_ms": 2000 }
      ],
      "description": "Search the tool registry by keyword"
    },
    {
      "id": 6,
      "action": "repl",
      "commands": [
        { "input": "/mcp search \"query database\"", "delay_ms": 2000 }
      ],
      "description": "Search for database-related tools"
    },
    {
      "id": 7,
      "action": "shell",
      "command": "vibecli --agent \"Read the file /tmp/demo/readme.txt and summarize it\"",
      "description": "Run an agent that triggers on-demand schema loading for filesystem tools",
      "delay_ms": 8000
    },
    {
      "id": 8,
      "action": "repl",
      "commands": [
        { "input": "/mcp lazy metrics", "delay_ms": 2000 }
      ],
      "description": "View cache metrics and context savings after the agent run"
    },
    {
      "id": 9,
      "action": "Narrate",
      "value": "The agent loaded only the filesystem:read_file schema on demand. Context savings are over 80%."
    },
    {
      "id": 10,
      "action": "repl",
      "commands": [
        { "input": "/mcp lazy cache", "delay_ms": 1500 }
      ],
      "description": "View which schemas are currently cached"
    },
    {
      "id": 11,
      "action": "repl",
      "commands": [
        { "input": "/mcp lazy pin filesystem:read_file filesystem:write_file", "delay_ms": 1500 }
      ],
      "description": "Pin frequently used tools so they are never evicted"
    },
    {
      "id": 12,
      "action": "repl",
      "commands": [
        { "input": "/mcp lazy preload github", "delay_ms": 3000 }
      ],
      "description": "Preload all GitHub tool schemas into the cache"
    },
    {
      "id": 13,
      "action": "repl",
      "commands": [
        { "input": "/mcp lazy metrics", "delay_ms": 2000 }
      ],
      "description": "View updated metrics after preloading and pinning"
    },
    {
      "id": 14,
      "action": "shell",
      "command": "cd vibeui && npm run tauri dev",
      "description": "Launch VibeUI to explore the MCP Lazy panel",
      "delay_ms": 8000
    },
    {
      "id": 15,
      "action": "Navigate",
      "target": "panel://mcp",
      "description": "Open the MCP panel in VibeUI"
    },
    {
      "id": 16,
      "action": "Click",
      "target": ".tab-lazy-registry",
      "description": "View the Tool Registry tab with loaded/unloaded status indicators"
    },
    {
      "id": 17,
      "action": "Screenshot",
      "label": "mcp-lazy-registry",
      "description": "Capture the tool registry showing cached vs uncached tools"
    },
    {
      "id": 18,
      "action": "Click",
      "target": ".tab-lazy-search",
      "description": "Switch to the Search tab"
    },
    {
      "id": 19,
      "action": "Type",
      "target": ".lazy-search-input",
      "value": "create issue",
      "description": "Search for issue-creation tools"
    },
    {
      "id": 20,
      "action": "Screenshot",
      "label": "mcp-lazy-search",
      "description": "Capture search results ranked by relevance"
    },
    {
      "id": 21,
      "action": "Click",
      "target": ".tab-lazy-metrics",
      "description": "Switch to the Metrics dashboard"
    },
    {
      "id": 22,
      "action": "Screenshot",
      "label": "mcp-lazy-metrics",
      "description": "Capture the context savings chart and cache statistics"
    },
    {
      "id": 23,
      "action": "repl",
      "commands": [
        { "input": "/mcp lazy clear", "delay_ms": 1000 },
        { "input": "/mcp lazy metrics", "delay_ms": 1500 }
      ],
      "description": "Clear the cache and verify it is empty"
    }
  ]
}