LangChain Core Workflow B: Agents & Tools

Overview

Build autonomous agents that use tools, make decisions, and execute multi-step tasks. Covers tool definition with Zod schemas, createToolCallingAgent, AgentExecutor, streaming agent output, and conversation memory.

Prerequisites

• Completed langchain-core-workflow-a (chains)
• npm install langchain @langchain/core @langchain/openai zod

Step 1: Define Tools (TypeScript)

import { tool } from "@langchain/core/tools";
import { z } from "zod";

// Tool with Zod schema validation
const calculator = tool(
  async ({ expression }) => {