Cloudflare Agents

Agents are persistent, stateful execution environments for agentic workloads, powered by Cloudflare Durable Objects. Each agent has its own state, storage, and lifecycle — with built-in support for real-time communication, scheduling, AI model calls, MCP, workflows, and more.

Agents hibernate when idle and wake on demand. You can run millions of them — one per user, per session, per game room — each costs nothing when inactive.

npm create cloudflare@latest -- --template cloudflare/agents-starter

Or add to an existing project:

npm install agents

Read the docs — getting started, API reference, guides, and more.

Quick Example

A counter agent with persistent state, callable methods, and real-time sync to a React frontend:

// server.ts
import { Agent, routeAgentRequest, callable } from "agents";

export type CounterState = { count: number };

export class CounterAgent extends Agent<Env, CounterState> {
  initialState = { count: 0 };

  @callable()
  increment() {
    this.setState({ count: this.state.count + 1 });
    return this.state.count;
  }

  @callable()
  decrement() {
    this.setState({ count: this.state.count - 1 });
    return this.state.count;
  }
}

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  }
};

// client.tsx
import { useAgent } from "agents/react";
import { useState } from "react";
import type { CounterAgent, CounterState } from "./server";

function Counter() {
  const [count, setCount] = useState(0);

  const agent = useAgent<CounterAgent, CounterState>({
    agent: "CounterAgent",
    onStateUpdate: (state) => setCount(state.count)
  });

  return (
    <div>
      <span>{count}</span>
      <button onClick={() => agent.stub.increment()}>+</button>
      <button onClick={() => agent.stub.decrement()}>-</button>
    </div>
  );
}

State changes sync to all connected clients automatically. Call methods like they're local functions.

The agent is a Durable Object, so it needs a binding and a SQLite migration in wrangler.jsonc:

{
  "name": "counter",
  "main": "server.ts",
  "compatibility_date": "2026-01-28",
  "compatibility_flags": ["nodejs_compat"],
  "durable_objects": {
    "bindings": [{ "name": "CounterAgent", "class_name": "CounterAgent" }]
  },
  "migrations": [{ "tag": "v1", "new_sqlite_classes": ["CounterAgent"] }]
}

Features

Feature	Description
Persistent State	Syncs to all connected clients, survives restarts
Callable Methods	Type-safe RPC via the @callable() decorator
Scheduling	One-time, recurring, and cron-based tasks
WebSockets	Real-time bidirectional communication with lifecycle hooks
AI Chat	Message persistence, resumable streaming, server/client tool execution
MCP	Act as MCP servers or connect as MCP clients (HTTP, SSE, RPC, elicitation)
WebMCP	Expose browser-side tools to agents over WebSocket
Workflows	Durable multi-step tasks with human-in-the-loop approval
Email	Send, receive, and reply via Cloudflare Email Service
Voice	Continuous STT, streaming TTS, VAD, interruption, SFU utilities
Browser Agents	Run agents in the browser tab with agents/browser
Code Mode	LLMs generate executable TypeScript instead of individual tool calls
Sandboxed Execution	Run generated code inside an isolated Worker with a virtual filesystem
x402 Payments	Pay-per-call APIs and tools via the x402 protocol
Observability	Built-in tracing, metrics, and structured logs
SQL	Direct SQLite queries via Durable Objects
React Hooks	useAgent, useAgentChat, useVoiceAgent for frontend integration
Vanilla JS Client	AgentClient and VoiceClient for non-React environments

Packages

Package	Description
agents	Core SDK — Agent class, routing, state, scheduling, MCP, email, workflows, x402, browser agents
@cloudflare/ai-chat	Higher-level AI chat — persistent messages, resumable streaming, tool execution
@cloudflare/think	Opinionated chat agent base — agentic loop, stream resumption, client tools, workspace tools
@cloudflare/codemode	LLMs write executable code that calls your tools, instead of one tool call at a time
@cloudflare/shell	Sandboxed JS execution + virtual filesystem (Workspace) for agents
@cloudflare/voice	Voice pipeline — STT, TTS, VAD, streaming, SFU utilities
@cloudflare/worker-bundler	Build and bundle Workers at runtime, for use with the Worker Loader binding
hono-agents	Hono middleware for adding agents to Hono apps

AI-chat modules used to live in agents/ai-chat-agent, agents/chat, agents/ai-react, and agents/ai-types. Those entry points still re-export, but they're deprecated — import from @cloudflare/ai-chat directly. New chat-from-scratch projects should look at @cloudflare/think.

Examples

The examples/ directory has 30+ self-contained demos. A non-exhaustive tour:

• Showcase — playground/ is the kitchen-sink app: state, callable methods, scheduling, chat, tools, MCP, workflows, email, voice — all in one UI
• Chat & assistants — assistant/, workspace-chat/, resumable-stream-chat/, structured-input/, dynamic-tools/
• MCP — mcp/, mcp-client/, mcp-worker/, mcp-worker-authenticated/, mcp-elicitation/, mcp-rpc-transport/, webmcp/
• Code Mode & sandboxes — codemode/, codemode-mcp/, codemode-mcp-openapi/, dynamic-workers/, dynamic-workers-playground/, worker-bundler-playground/
• Voice — voice-agent/, voice-input/, elevenlabs-starter/
• Workflows & approvals — workflows/, a2a/
• Auth, payments, comms — auth-agent/, cross-domain/, x402/, x402-mcp/, email-agent/, github-webhook/, push-notifications/
• Game & misc — tictactoe/, ai-chat/

Examples using the OpenAI Agents SDK live in openai-sdk/. Work-in-progress experiments live in experimental/ (no stability guarantees).

Run any example locally:

cd examples/playground
npm start

Documentation

• Full docs on developers.cloudflare.com
• docs/ directory in this repo (synced upstream)
• Anthropic Patterns guide — sequential, routing, parallel, orchestrator, evaluator
• Human-in-the-Loop guide — approval workflows with pause/resume
• design/ — architecture and design decision records (chat API, sub-agents RFC, workspace, voice, browser tools, retries, and more)

Repository Structure

Directory	Description
packages/agents/	Core SDK
packages/ai-chat/	AI chat layer
packages/think/	Opinionated chat agent base
packages/codemode/	Code Mode
packages/shell/	Sandboxed execution + filesystem
packages/voice/	Voice pipeline
packages/worker-bundler/	Runtime Workers bundler
packages/hono-agents/	Hono integration
examples/	Self-contained demo apps
experimental/	Work-in-progress experiments (not published)
openai-sdk/	Examples using the OpenAI Agents SDK
guides/	In-depth pattern tutorials
docs/	Markdown docs synced to developers.cloudflare.com
site/	Deployed websites (agents.cloudflare.com, AI playground)
design/	Architecture and design decision records
scripts/	Repo-wide tooling

Development

Node 24+ required. npm workspaces with Nx for task orchestration, caching, and affected detection.

npm install                  # install all workspaces
npm run build                # build all packages (Nx, cached, dependency-ordered)
npm run check                # sherif + export checks + oxfmt + oxlint + typecheck
npm run test                 # vitest + vitest-pool-workers (Workers runtime)
npm run test:react           # Playwright-based React hook tests
npx nx affected -t build     # build only what changed
npx nx affected -t test      # test only what changed

Changes to packages/ need a changeset:

npx changeset

See AGENTS.md for deeper contributor guidance.

Contributing

We are not accepting external pull requests at this time — the SDK is evolving quickly and we want to keep the surface area manageable. That said, we'd love to hear from you:

• Bug reports & feature requests — open an issue
• Questions & ideas — start a discussion

License

MIT