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SKILL.md
npx skills add cloudflare/skills --skill agents-sdk
Build, debug, or review Cloudflare Agents SDK applications using the agents package.
npx skills add cloudflare/skills --skill agents-sdk
Your knowledge of the Agents SDK may be outdated. Prefer retrieval over pre-training for any Agents SDK task.
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, AgentClient, state, RPC, HTTP |
| Client tools | Client tools | Client-side tools, autoContinueAfterToolResult |
| Server-driven messages | Autonomous responses | saveMessages, waitUntilStable, server-initiated turns |
| Resumable streaming | Chat agents | Stream recovery on disconnect |
| Email routing, secure reply resolver | ||
| MCP client | MCP client | Connecting to MCP servers |
| MCP server | MCP server | Building MCP servers with createMcpHandler |
| 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 | Workflow approvals, elicitation, timeout handling |
| 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 |
The Agents SDK provides:
setState@callable() methods invoked over WebSocketscheduleEvery), and cron tasksAgentWorkflowrunFiber() / stash() for work that survives DO evictionqueue()this.retry() with exponential backoff and jittercreateMcpHandlerAIChatAgent with resumable streams, message persistence, toolssaveMessages, waitUntilStable for proactive agent turnsuseAgent, useAgentChat for client appsdiagnostics_channel events for state, RPC, schedule, lifecycle@cloudflare/voiceagents/browser@cloudflare/thinkIf not installed:
For chat agents:
Gotchas:
experimentalDecorators in tsconfig (breaks @callable)"ai": { "binding": "AI" } for Workers AIRequests 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).
| 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?) |
Read client-sdk.md for client selection and current connection examples. For chat UI and tools, also read streaming-chat.md.
getAgentByNameuseAgent, useAgentChat, AgentClientsaveMessagesneedsApprovalrunFiber, stash, surviving eviction@cloudflare/think higher-level chat agent@cloudflare/voice STT/TTS{
"compatibility_flags": ["nodejs_compat"],
"durable_objects": {
"bindings": [{ "name": "MyAgent", "class_name": "MyAgent" }]
},
"migrations": [{ "tag": "v1", "new_sqlite_classes": ["MyAgent"] }]
}import { Agent, routeAgentRequest, callable } 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 })
};