From One Tool to a Toolkit

Real agents need multiple tools. The key challenge: how does the agent decide which tool to use?

Multi-Tool Agent

const tools = [
  {
    name: "search_web",
    description: "Search the web for current information. Use for recent events or facts. Do NOT use for general knowledge.",
    input_schema: { type: "object", properties: { query: { type: "string" } }, required: ["query"] }
  },
  {
    name: "read_file",
    description: "Read a local file. Use when user references a file by name.",
    input_schema: { type: "object", properties: { path: { type: "string" } }, required: ["path"] }
  },
  {
    name: "run_code",
    description: "Execute JavaScript. Use for calculations. NEVER for file modifications.",
    input_schema: { type: "object", properties: { code: { type: "string" } }, required: ["code"] }
  }
];

The Tool Router Pattern

async function executeTool(name: string, args: any) {
  switch (name) {
    case "search_web":  return await searchWeb(args.query);
    case "read_file":   return await readFile(args.path);
    case "run_code":    return await runCode(args.code);
    default:            return { error: `Unknown tool: ${name}` };
  }
}

Key Design Rules