What is Cloudflare Agents SDK?

Cloudflare Agents SDK is a coding tool. SDK for building stateful AI agents on Cloudflare Workers and Durable Objects.

What is Cloudflare Agents SDK best for?

ai-agents, framework, agent-sdk. It is filed under Coding.

Cloudflare Agents SDK · Scriptiii AI Tools

// 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>
  );
}

{
  "name": "counter",
  "main": "server.ts",
  "compatibility_date": "2026-06-11",
  "compatibility_flags": ["nodejs_compat"],
  "durable_objects": {
    "bindings": [{ "name": "CounterAgent", "class_name": "CounterAgent" }]
  },
  "migrations": [{ "tag": "v1", "new_sqlite_classes": ["CounterAgent"] }]
}

Feature	Description
Persistent State	Syncs to all connected clients, survives restarts
Callable Methods	Type-safe RPC via the `@callable()` decorator
Sub-agents	Parent/child DO composition via facets, nested routing, and typed parent lookup
Agent Tools	Run chat-capable sub-agents as tools with streaming child timelines
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 page-local tools or bridge remote MCP tools to browser agents
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

Package	Description
`agents`	Core SDK — Agents, routing, Voice, Channels, scheduling, MCP, 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`	Deprecated: use `@cloudflare/computer` workspaces
`@cloudflare/voice`	Deprecated compatibility wrapper for the `agents/voice` exports
`@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

Directory	Description
`packages/agents/`	Core SDK
`packages/ai-chat/`	AI chat layer
`packages/think/`	Opinionated chat agent base
`packages/codemode/`	Code Mode
`packages/shell/`	Deprecated sandboxed execution + filesystem
`packages/voice/`	Deprecated Voice compatibility wrapper
`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

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

Cloudflare Agents SDK

What it does

Cloudflare Agents

Cloudflare Agents SDK

What it does

Cloudflare Agents

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