Cloudflare Agents SDK
Build stateful AI agents and workflows on Cloudflare Workers with real-time capabilities.
Installation
- Make sure Claude is on your device and in your terminal.
Skills load from
~/.claude/skills/when Claude Code starts up — so you need it on your machine first. If you don't have it yet, install it once with the command below, then runclaudein any terminal to verify.One-time setupnpm i -g @anthropic-ai/claude-codeAlready have it? Skip ahead.
- Paste into Claude Code or into your terminal.
This copies the whole skill folder into
~/.claude/skills/agents-sdk-xiaomimimo/— the SKILL.md plus any scripts, reference docs, or templates the skill ships with. Safe default: works for every skill.Faster alternative (instruction-only skills)
Skips the clone and grabs only the SKILL.md file. Don't use this if the skill ships Python scripts, reference markdowns, or asset templates — they won't be downloaded and the skill will fail when it tries to load them.
Quick install (SKILL.md only)Sign up to copy - Restart Claude Code.
Quit and reopen Claude Code (or any other agent that loads from
~/.claude/skills/). New skills are picked up on startup. - Just ask Claude.
Skills auto-activate when your request matches the skill's description — no slash command needed. Trigger phrases live in the skill's own frontmatter; you can read them in the “What this skill does” section above.
Prefer to read the source first? Open on GitHub.
When Claude uses it
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, or chat applications. Covers Agent class, state management, callable RPC, Workflows integration, and React hooks.
What this skill does
Cloudflare Agents SDK
STOP. Your knowledge of the Agents SDK may be outdated. Prefer retrieval over pre-training for any Agents SDK task.
Documentation
Fetch current docs from https://github.com/cloudflare/agents/tree/main/docs before implementing.
| Topic | Doc | Use for |
|---|---|---|
| Getting started | docs/getting-started.md | First agent, project setup |
| State | docs/state.md | setState, validateStateChange, persistence |
| Routing | docs/routing.md | URL patterns, routeAgentRequest, basePath |
| Callable methods | docs/callable-methods.md | @callable, RPC, streaming, timeouts |
| Scheduling | docs/scheduling.md | schedule(), scheduleEvery(), cron |
| Workflows | docs/workflows.md | AgentWorkflow, durable multi-step tasks |
| HTTP/WebSockets | docs/http-websockets.md | Lifecycle hooks, hibernation |
docs/email.md | Email routing, secure reply resolver | |
| MCP client | docs/mcp-client.md | Connecting to MCP servers |
| MCP server | docs/mcp-servers.md | Building MCP servers with McpAgent |
| Client SDK | docs/client-sdk.md | useAgent, useAgentChat, React hooks |
| Human-in-the-loop | docs/human-in-the-loop.md | Approval flows, pausing workflows |
| Resumable streaming | docs/resumable-streaming.md | Stream recovery on disconnect |
Cloudflare docs: https://developers.cloudflare.com/agents/
Capabilities
The Agents SDK provides:
- Persistent state - SQLite-backed, auto-synced to clients
- Callable RPC -
@callable()methods invoked over WebSocket - Scheduling - One-time, recurring (
scheduleEvery), and cron tasks - Workflows - Durable multi-step background processing via
AgentWorkflow - MCP integration - Connect to MCP servers or build your own with
McpAgent - Email handling - Receive and reply to emails with secure routing
- Streaming chat -
AIChatAgentwith resumable streams - React hooks -
useAgent,useAgentChatfor client apps
FIRST: Verify Installation
npm ls agents # Should show agents package
If not installed:
npm install agents
Wrangler Configuration
{
"durable_objects": {
"bindings": [{ "name": "MyAgent", "class_name": "MyAgent" }],
},
"migrations": [{ "tag": "v1", "new_sqlite_classes": ["MyAgent"] }],
}
Agent Class
import { Agent, routeAgentRequest, callable } from "agents"
type State = { count: number }
export class Counter extends Agent<Env, State> {
initialState = { count: 0 }
// Validation hook - runs before state persists (sync, throwing rejects the update)
validateStateChange(nextState: State, source: Connection | "server") {
if (nextState.count < 0) throw new Error("Count cannot be negative")
}
// Notification hook - runs after state persists (async, non-blocking)
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" })
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) |
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
- references/workflows.md - Durable Workflows integration
- references/callable.md - RPC methods, streaming, timeouts
- references/state-scheduling.md - State persistence, scheduling
- references/streaming-chat.md - AIChatAgent, resumable streams
- references/mcp.md - MCP server integration
- references/email.md - Email routing and handling
- references/codemode.md - Code Mode (experimental)
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