| name | agents-sdk |
| description | Build AI agents on Cloudflare Workers using the Agents SDK. Load when creating stateful agents, durable workflows, real-time WebSocket apps, scheduled tasks, MCP servers, chat applications, voice agents, or browser automation. Covers Agent class, state management, callable RPC, Workflows, durable execution, queues, retries, observability, and React hooks. Biases towards retrieval from Cloudflare docs over pre-trained knowledge. |
Cloudflare Agents SDK
Your knowledge of the Agents SDK may be outdated. Prefer retrieval over pre-training for any Agents SDK task.
Retrieval Sources
Cloudflare docs: https://developers.cloudflare.com/agents/
| Topic | Docs URL | Use for |
|---|
| Getting started | Quick start | First agent, project setup |
| Adding to existing project | Add to existing project | Install into existing Workers app |
| Configuration | Configuration | wrangler.jsonc, bindings, assets, deployment |
| Agent class | Agents API | Agent lifecycle, patterns, pitfalls |
| State | Store and sync state | setState, validateStateChange, persistence |
| Routing | Routing | URL patterns, routeAgentRequest |
| Callable methods | Callable methods | @callable, RPC, streaming, timeouts |
| Scheduling | Schedule tasks | schedule(), scheduleEvery(), cron |
| Workflows | Run workflows | AgentWorkflow, durable multi-step tasks |
| HTTP/WebSockets | WebSockets | Lifecycle hooks, hibernation |
| Chat agents | Chat agents | AIChatAgent, streaming, tools, persistence |
| Client SDK | Client SDK | useAgent, useAgentChat, React hooks |
| Client tools | Client tools | Client-side tools, autoContinueAfterToolResult |
| Server-driven messages | Trigger patterns | saveMessages, waitUntilStable, server-initiated turns |
| Resumable streaming | Resumable streaming | Stream recovery on disconnect |
| Email | Email | Email routing, secure reply resolver |
| MCP client | MCP client | Connecting to MCP servers |
| MCP server | MCP server | Building MCP servers with McpAgent |
| MCP transports | MCP transports | Streamable HTTP, SSE, RPC transport options |
| Securing MCP servers | Securing MCP | OAuth, proxy MCP, hardening |
| Human-in-the-loop | Human-in-the-loop | Approval flows, needsApproval, workflows |
| Durable execution | Durable execution | runFiber(), stash(), surviving DO eviction |
| Queue | Queue | Built-in FIFO queue, queue() |
| Retries | Retries | this.retry(), backoff/jitter |
| Observability | Observability | Diagnostics-channel events |
| Push notifications | Push notifications | Web Push + VAPID from agents |
| Webhooks | Webhooks | Receiving external webhooks |
| Cross-domain auth | Cross-domain auth | WebSocket auth, tokens, CORS |
| Readonly connections | Readonly | shouldConnectionBeReadonly |
| Voice | Voice | Experimental STT/TTS, withVoice |
| Browse the web | Browser tools | Experimental CDP browser automation |
| Think | Think | Experimental higher-level chat agent class |
| Migrations | AI SDK v5, AI SDK v6 | Upgrading @cloudflare/ai-chat |
Install
Check first: npm ls agents. If missing: npm install agents.
Chat agents additionally need: npm install @cloudflare/ai-chat ai @ai-sdk/react
Wrangler Configuration
{
"compatibility_flags": ["nodejs_compat"],
"durable_objects": {
"bindings": [{ "name": "MyAgent", "class_name": "MyAgent" }]
},
"migrations": [{ "tag": "v1", "new_sqlite_classes": ["MyAgent"] }]
}
Gotchas:
- Do NOT enable
experimentalDecorators in tsconfig (breaks @callable)
- Never edit old migrations: always add new tags
- Each agent class needs its own DO binding + migration entry
- Add
"ai": { "binding": "AI" } for Workers AI
Agent Class
import { Agent, routeAgentRequest, callable, type Connection } from "agents";
type State = { count: number };
export class Counter extends Agent<Env, State> {
initialState = { count: 0 };
validateStateChange(nextState: State, source: Connection | "server") {
if (nextState.count < 0) throw new Error("Count cannot be negative");
}
onStateUpdate(state: State, source: Connection | "server") {
console.log("State updated:", state);
}
@callable()
increment() {
this.setState({ count: this.state.count + 1 });
return this.state.count;
}
}
export default {
fetch: (req, env) => routeAgentRequest(req, env) ?? new Response("Not found", { status: 404 })
};
Routing
Requests route to /agents/{agent-name}/{instance-name}:
| Class | URL |
|---|
Counter | /agents/counter/user-123 |
ChatRoom | /agents/chat-room/lobby |
Client: useAgent({ agent: "Counter", name: "user-123" })
Custom routing: use getAgentByName(env.MyAgent, "instance-id") then agent.fetch(request).
Core APIs
| Task | API |
|---|
| Read state | this.state.count |
| Write state | this.setState({ count: 1 }) |
| SQL query | this.sql`SELECT * FROM users WHERE id = ${id}` |
| Schedule (delay) | await this.schedule(60, "task", payload) |
| Schedule (cron) | await this.schedule("0 * * * *", "task", payload) |
| Schedule (interval) | await this.scheduleEvery(30, "poll") |
| RPC method | @callable() myMethod() { ... } |
| Streaming RPC | @callable({ streaming: true }) stream(res) { ... } |
| Start workflow | await this.runWorkflow("ProcessingWorkflow", params) |
| Durable fiber | await this.runFiber("name", async (ctx) => { ... }) |
| Enqueue work | this.queue("handler", payload) |
| Retry with backoff | await this.retry(fn, { maxAttempts: 5 }) |
| Broadcast to clients | this.broadcast(message) |
| Get connections | this.getConnections(tag?) |
React Client
import { useAgent } from "agents/react";
function App() {
const [state, setLocalState] = useState({ count: 0 });
const agent = useAgent({
agent: "Counter",
name: "my-instance",
onStateUpdate: (newState) => setLocalState(newState),
onIdentity: (name, agentType) => console.log(`Connected to ${name}`)
});
return (
<button onClick={() => agent.setState({ count: state.count + 1 })}>
Count: {state.count}
</button>
);
}
References
Core
Chat & Streaming
Background Processing
Integrations
Experimental
