---
title: Getting started
description: Build a Think chat agent with persistent memory, built-in file tools, custom tools, and streaming, step by step.
image: https://developers.cloudflare.com/dev-products-preview.png
---

> Documentation Index  
> Fetch the complete documentation index at: https://developers.cloudflare.com/agents/llms.txt  
> Use this file to discover all available pages before exploring further. 

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# Getting started

Build a chat agent with persistent memory, built-in file tools, and streaming — step by step.

If you are brand new to Cloudflare Agents, skim [What are agents?](https://developers.cloudflare.com/agents/concepts/what-are-agents/) first for the core ideas. Otherwise, you can follow along here from scratch.

By the end of this tutorial you will have a Think agent that:

* Streams responses to a React chat UI
* Has persistent memory the model can read and write
* Includes workspace file tools (read, write, edit, find, grep, delete)
* Supports custom server-side tools

## Prerequisites

* Node.js 24+
* A Cloudflare account with Workers AI access
* Familiarity with TypeScript and Cloudflare Workers

## 1\. Create a project

Terminal window

```
mkdir my-think-agent && cd my-think-agentnpm init -y
```

Install dependencies:

Terminal window

```
npm install @cloudflare/think @cloudflare/ai-chat agents ai @cloudflare/shell zod workers-ai-provider react react-domnpm install -D wrangler @cloudflare/vite-plugin @cloudflare/workers-types @vitejs/plugin-react @tailwindcss/vite tailwindcss typescript vite
```

## 2\. Configure wrangler

Create `wrangler.jsonc`:

* [  wrangler.jsonc ](#tab-panel-5817)
* [  wrangler.toml ](#tab-panel-5818)

JSONC

```
{  "name": "my-think-agent",  "compatibility_date": "2026-01-28",  "compatibility_flags": ["nodejs_compat"],  "ai": { "binding": "AI" },  "assets": {    "not_found_handling": "single-page-application",    "run_worker_first": ["/agents/*"]  },  "durable_objects": {    "bindings": [{ "class_name": "MyAgent", "name": "MyAgent" }]  },  "migrations": [{ "new_sqlite_classes": ["MyAgent"], "tag": "v1" }],  "main": "src/server.ts"}
```

TOML

```
name = "my-think-agent"compatibility_date = "2026-01-28"compatibility_flags = [ "nodejs_compat" ]main = "src/server.ts"
[ai]binding = "AI"
[assets]not_found_handling = "single-page-application"run_worker_first = [ "/agents/*" ]
[[durable_objects.bindings]]class_name = "MyAgent"name = "MyAgent"
[[migrations]]new_sqlite_classes = [ "MyAgent" ]tag = "v1"
```

Create `vite.config.ts`:

* [  JavaScript ](#tab-panel-5819)
* [  TypeScript ](#tab-panel-5820)

JavaScript

```
import { cloudflare } from "@cloudflare/vite-plugin";import tailwindcss from "@tailwindcss/vite";import react from "@vitejs/plugin-react";import { defineConfig } from "vite";
export default defineConfig({  plugins: [react(), cloudflare(), tailwindcss()],});
```

TypeScript

```
import { cloudflare } from "@cloudflare/vite-plugin";import tailwindcss from "@tailwindcss/vite";import react from "@vitejs/plugin-react";import { defineConfig } from "vite";
export default defineConfig({  plugins: [react(), cloudflare(), tailwindcss()],});
```

Create `tsconfig.json`:

```
{  "extends": "agents/tsconfig"}
```

## 3\. Define the agent

Create `src/server.ts`:

* [  JavaScript ](#tab-panel-5821)
* [  TypeScript ](#tab-panel-5822)

JavaScript

```
import { Think } from "@cloudflare/think";import { createWorkersAI } from "workers-ai-provider";import { routeAgentRequest } from "agents";
export class MyAgent extends Think {  getModel() {    return createWorkersAI({ binding: this.env.AI })(      "@cf/moonshotai/kimi-k2.6",    );  }
  getSystemPrompt() {    return "You are a helpful assistant with access to a workspace filesystem.";  }}
export default {  async fetch(request, env) {    return (      (await routeAgentRequest(request, env)) ||      new Response("Not found", { status: 404 })    );  },};
```

TypeScript

```
import { Think } from "@cloudflare/think";import { createWorkersAI } from "workers-ai-provider";import { routeAgentRequest } from "agents";
export class MyAgent extends Think<Env> {  getModel() {    return createWorkersAI({ binding: this.env.AI })(      "@cf/moonshotai/kimi-k2.6",    );  }
  getSystemPrompt() {    return "You are a helpful assistant with access to a workspace filesystem.";  }}
export default {  async fetch(request: Request, env: Env) {    return (      (await routeAgentRequest(request, env)) ||      new Response("Not found", { status: 404 })    );  },} satisfies ExportedHandler<Env>;
```

This is a working agent. Think automatically provides:

* WebSocket chat protocol (compatible with `useAgentChat`)
* Message persistence in SQLite
* Resumable streaming (page refresh replays buffered chunks)
* Workspace file tools (read, write, edit, list, find, grep, delete)
* Abort/cancel support
* Error handling with partial message persistence

## 4\. Connect a React client

Create `src/client.tsx`:

* [  JavaScript ](#tab-panel-5829)
* [  TypeScript ](#tab-panel-5830)

JavaScript

```
import { createRoot } from "react-dom/client";import { useAgent } from "agents/react";import { useAgentChat } from "@cloudflare/ai-chat/react";
function Chat() {  const agent = useAgent({ agent: "MyAgent" });  const { messages, sendMessage, status } = useAgentChat({ agent });
  return (    <div>      <h1>Think Agent</h1>      {messages.map((msg) => (        <div key={msg.id}>          <strong>{msg.role}:</strong>          {msg.parts.map((part, i) =>            part.type === "text" ? <span key={i}>{part.text}</span> : null,          )}        </div>      ))}
      <form        onSubmit={(e) => {          e.preventDefault();          const input = e.currentTarget.elements.namedItem("input");          if (!input.value.trim()) return;          sendMessage({ text: input.value });          input.value = "";        }}      >        <input name="input" placeholder="Send a message..." />        <button type="submit">Send</button>      </form>
      <p>Status: {status}</p>    </div>  );}
const root = document.getElementById("root");if (root) {  createRoot(root).render(<Chat />);}
```

TypeScript

```
import { createRoot } from "react-dom/client";import { useAgent } from "agents/react";import { useAgentChat } from "@cloudflare/ai-chat/react";
function Chat() {  const agent = useAgent({ agent: "MyAgent" });  const { messages, sendMessage, status } = useAgentChat({ agent });
  return (    <div>      <h1>Think Agent</h1>      {messages.map((msg) => (        <div key={msg.id}>          <strong>{msg.role}:</strong>          {msg.parts.map((part, i) =>            part.type === "text" ? <span key={i}>{part.text}</span> : null,          )}        </div>      ))}
      <form        onSubmit={(e) => {          e.preventDefault();          const input = e.currentTarget.elements.namedItem(            "input",          ) as HTMLInputElement;          if (!input.value.trim()) return;          sendMessage({ text: input.value });          input.value = "";        }}      >        <input name="input" placeholder="Send a message..." />        <button type="submit">Send</button>      </form>
      <p>Status: {status}</p>    </div>  );}
const root = document.getElementById("root");if (root) {  createRoot(root).render(<Chat />);}
```

Create `index.html`:

```
<!doctype html><html lang="en">  <head>    <meta charset="UTF-8" />    <meta name="viewport" content="width=device-width, initial-scale=1.0" />    <title>Think Agent</title>  </head>  <body>    <div id="root"></div>    <script type="module" src="/src/client.tsx"></script>  </body></html>
```

## 5\. Run it

Terminal window

```
npx vite dev
```

Open the browser and send a message. The agent responds with streaming text, and workspace file tools are available to the model automatically.

## 6\. Add persistent memory

Override `configureSession` to give the model writable memory that survives restarts:

* [  JavaScript ](#tab-panel-5823)
* [  TypeScript ](#tab-panel-5824)

JavaScript

```
export class MyAgent extends Think {  getModel() {    return createWorkersAI({ binding: this.env.AI })(      "@cf/moonshotai/kimi-k2.6",    );  }
  configureSession(session) {    return session      .withContext("soul", {        provider: {          get: async () =>            "You are a helpful assistant. Remember important facts about the user.",        },      })      .withContext("memory", {        description: "Important facts about the user and conversation.",        maxTokens: 2000,      })      .withCachedPrompt();  }}
```

TypeScript

```
export class MyAgent extends Think<Env> {  getModel(): LanguageModel {    return createWorkersAI({ binding: this.env.AI })(      "@cf/moonshotai/kimi-k2.6",    );  }
  configureSession(session: Session) {    return session      .withContext("soul", {        provider: {          get: async () =>            "You are a helpful assistant. Remember important facts about the user.",        },      })      .withContext("memory", {        description: "Important facts about the user and conversation.",        maxTokens: 2000,      })      .withCachedPrompt();  }}
```

Now the model sees a `MEMORY` section in its system prompt and gets a `set_context` tool to update it. Facts written to memory persist in SQLite and survive Durable Object hibernation and restarts.

When you use `configureSession`, the system prompt is built from context blocks rather than `getSystemPrompt()`. The `"soul"` block above acts as the system identity — it is read-only and always appears first. The `"memory"` block is writable, and the model proactively updates it when it learns something useful.

Refer to the [Sessions documentation](https://developers.cloudflare.com/agents/runtime/lifecycle/sessions/) for context blocks, compaction, search, skills, and multi-session support.

## 7\. Add custom tools

Override `getTools()` to add your own tools alongside the built-in workspace tools:

* [  JavaScript ](#tab-panel-5827)
* [  TypeScript ](#tab-panel-5828)

JavaScript

```
import { tool } from "ai";import { z } from "zod";
export class MyAgent extends Think {  getModel() {    /* ... */  }  configureSession(session) {    /* ... */  }
  getTools() {    return {      getWeather: tool({        description: "Get the current weather for a city",        inputSchema: z.object({          city: z.string().describe("City name"),        }),        execute: async ({ city }) => {          const res = await fetch(            `https://api.weatherapi.com/v1/current.json?key=${this.env.WEATHER_KEY}&q=${city}`,          );          return res.json();        },      }),    };  }}
```

TypeScript

```
import { tool } from "ai";import { z } from "zod";
export class MyAgent extends Think<Env> {  getModel(): LanguageModel {    /* ... */  }  configureSession(session: Session) {    /* ... */  }
  getTools(): ToolSet {    return {      getWeather: tool({        description: "Get the current weather for a city",        inputSchema: z.object({          city: z.string().describe("City name"),        }),        execute: async ({ city }) => {          const res = await fetch(            `https://api.weatherapi.com/v1/current.json?key=${this.env.WEATHER_KEY}&q=${city}`,          );          return res.json();        },      }),    };  }}
```

Think merges tools from multiple sources automatically. On every turn, the model has access to:

1. **Workspace tools** — read, write, edit, list, find, grep, delete, bash (built-in)
2. **Your tools** — from `getTools()`
3. **Extension tools** — from loaded extensions
4. **Session tools** — set\_context, load\_context, search\_context (from `configureSession`)
5. **Skill tools** — activate\_skill, read\_skill\_resource, and optional run\_skill\_script (from `getSkills()`)
6. **MCP tools** — from connected MCP servers (if any)
7. **Client tools** — from the browser (if any)

## 8\. Add lifecycle hooks

Think provides hooks that fire on every turn, regardless of entry path:

* [  JavaScript ](#tab-panel-5825)
* [  TypeScript ](#tab-panel-5826)

JavaScript

```
export class MyAgent extends Think {  getModel() {    /* ... */  }
  beforeTurn(ctx) {    console.log(      `Turn starting: ${Object.keys(ctx.tools).length} tools available`,    );  }
  onChatResponse(result) {    console.log(`Turn ${result.status}: ${result.message.parts.length} parts`);  }}
```

TypeScript

```
import type {  TurnContext,  TurnConfig,  ChatResponseResult,} from "@cloudflare/think";
export class MyAgent extends Think<Env> {  getModel(): LanguageModel {    /* ... */  }
  beforeTurn(ctx: TurnContext): TurnConfig | void {    console.log(      `Turn starting: ${Object.keys(ctx.tools).length} tools available`,    );  }
  onChatResponse(result: ChatResponseResult) {    console.log(`Turn ${result.status}: ${result.message.parts.length} parts`);  }}
```

Refer to [Lifecycle hooks](https://developers.cloudflare.com/agents/harnesses/think/lifecycle-hooks/) for the full reference.

## Next steps

* [Lifecycle hooks](https://developers.cloudflare.com/agents/harnesses/think/lifecycle-hooks/) — control model behavior, switch models per-turn, restrict tools
* [Tools](https://developers.cloudflare.com/agents/harnesses/think/tools/) — workspace tools, code execution, extensions
* [Client tools](https://developers.cloudflare.com/agents/harnesses/think/client-tools/) — browser-side tools, approval flows, concurrency
* [Sub-agent RPC and programmatic turns](https://developers.cloudflare.com/agents/harnesses/think/sub-agents/) — RPC streaming, scheduled turns, recovery
* [Sessions](https://developers.cloudflare.com/agents/runtime/lifecycle/sessions/) — context blocks, compaction, search, multi-session

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