// tools/database-tools/index.ts
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";

const server = new Server({ name: "database-tools", version: "1.0.0" }, {
  capabilities: { tools: {} }
});

server.setRequestHandler("tools/list", async () => ({
  tools: [
    {
      name: "query_database",
      description: "Run a read-only SQL query against the project database",
      inputSchema: {
        type: "object",
        properties: {
          sql: { type: "string", description: "SQL SELECT query" }
        },
        required: ["sql"]
      }
    },
    {
      name: "list_tables",
      description: "List all tables in the database",
      inputSchema: { type: "object", properties: {} }
    }
  ]
}));

server.setRequestHandler("tools/call", async (request) => {
  const { name, arguments: args } = request.params;

  if (name === "query_database") {
    // Only allow SELECT queries (safety!)
    if (!args.sql.trim().toUpperCase().startsWith("SELECT")) {
      return { content: [{ type: "text", text: "Error: Only SELECT queries allowed" }] };
    }
    // Execute against your database...
    const result = await db.query(args.sql);
    return { content: [{ type: "text", text: JSON.stringify(result, null, 2) }] };
  }

  if (name === "list_tables") {
    const tables = await db.query("SELECT tablename FROM pg_tables WHERE schemaname = 'public'");
    return { content: [{ type: "text", text: JSON.stringify(tables, null, 2) }] };
  }
});

const transport = new StdioServerTransport();
await server.connect(transport);

# .caged.yaml
template: node-20
resources:
  cpu: 2
  memory: 2048

secrets:
  - ANTHROPIC_API_KEY
  - DATABASE_URL

init_script: |
  npm install
  cd tools/database-tools && npm install

# Custom MCP servers to start alongside the built-in one
mcp_servers:
  - name: database-tools
    command: "node tools/database-tools/index.ts"
    env:
      DATABASE_URL: "${DATABASE_URL}"

Available tools:
  - read_file (built-in)
  - write_file (built-in)
  - run_terminal (built-in)
  - query_database (custom)     ← your tool!
  - list_tables (custom)        ← your tool!

// tools/deploy/index.ts
const tools = [
  {
    name: "deploy_staging",
    description: "Deploy the current branch to staging environment",
    inputSchema: {
      type: "object",
      properties: {
        branch: { type: "string" },
        message: { type: "string", description: "Deploy message" }
      },
      required: ["branch", "message"]
    }
  },
  {
    name: "check_staging_health",
    description: "Check if staging is healthy after deploy",
    inputSchema: { type: "object", properties: {} }
  }
];

// Handler
if (name === "deploy_staging") {
  // Safety: only allow staging, never production
  const result = await fetch("https://your-ci.com/api/deploy", {
    method: "POST",
    headers: { "Authorization": `Bearer ${process.env.CI_TOKEN}` },
    body: JSON.stringify({
      environment: "staging",  // hardcoded — agent can't deploy to prod
      branch: args.branch,
      message: args.message
    })
  });
  return { content: [{ type: "text", text: `Deploy triggered: ${await result.text()}` }] };
}

# .caged.yaml
mcp_servers:
  - name: monitoring
    command: "node tools/monitoring/index.ts"
    env:
      DATADOG_API_KEY: "${DATADOG_API_KEY}"
      GRAFANA_URL: "${GRAFANA_URL}"

// tools/monitoring/index.ts — Agent can check metrics
const tools = [
  { name: "get_error_rate", description: "Get current error rate for a service" },
  { name: "get_latency_p99", description: "Get P99 latency for a service" },
  { name: "get_recent_alerts", description: "Get alerts from the last hour" }
];

# Get the sandbox's MCP WebSocket endpoint
curl https://api.caged.dev/v1/sandboxes/cage-a1b2c3d4/mcp \
  -H "Authorization: Bearer caged_sk_..."

# Response:
# {"websocket_url": "wss://mcp.caged.dev/cage-a1b2c3d4"}