--- title: Agents SDK v0.8.0: readable state, idempotent schedules, typed AgentClient, and Zod 4 description: Agents SDK v0.8.0 exposes a readable state property on useAgent and AgentClient, makes schedule() idempotent for cron and opt-in for other types, adds full TypeScript inference to AgentClient, and drops Zod v3 in favor of Zod v4. image: https://developers.cloudflare.com/changelog-preview.png --- > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/changelog/llms.txt > Use this file to discover all available pages before exploring further. [Skip to content](#%5Ftop) # Changelog New updates and improvements at Cloudflare. [ Subscribe to RSS ](https://developers.cloudflare.com/changelog/rss/index.xml) [ View RSS feeds ](https://developers.cloudflare.com/fundamentals/new-features/available-rss-feeds/) ![hero image](https://developers.cloudflare.com/_astro/hero.CVYJHPAd_26AMqX.svg) [ ← Back to all posts ](https://developers.cloudflare.com/changelog/) ## Agents SDK v0.8.0: readable state, idempotent schedules, typed AgentClient, and Zod 4 Mar 23, 2026 [ Agents ](https://developers.cloudflare.com/agents/)[ Workers ](https://developers.cloudflare.com/workers/) The latest release of the [Agents SDK ↗](https://github.com/cloudflare/agents) exposes agent state as a readable property, prevents duplicate schedule rows across Durable Object restarts, brings full TypeScript inference to `AgentClient`, and migrates to Zod 4. #### Readable `state` on `useAgent` and `AgentClient` Both `useAgent` (React) and `AgentClient` (vanilla JS) now expose a `state` property that reflects the current agent state. Previously, reading state required manually tracking it through the `onStateUpdate` callback. **React (`useAgent`)** * [ JavaScript ](#tab-panel-2633) * [ TypeScript ](#tab-panel-2634) JavaScript ``` const agent = useAgent({ agent: "game-agent", name: "room-123",}); // Read state directly — no separate useState + onStateUpdate neededreturn
Score: {agent.state?.score}
; // Spread for partial updatesagent.setState({ ...agent.state, score: (agent.state?.score ?? 0) + 10 }); ``` TypeScript ``` const agent = useAgent({ agent: "game-agent", name: "room-123",}); // Read state directly — no separate useState + onStateUpdate neededreturn
Score: {agent.state?.score}
; // Spread for partial updatesagent.setState({ ...agent.state, score: (agent.state?.score ?? 0) + 10 }); ``` `agent.state` is reactive — the component re-renders when state changes from either the server or a client-side `setState()` call. **Vanilla JS (`AgentClient`)** * [ JavaScript ](#tab-panel-2635) * [ TypeScript ](#tab-panel-2636) JavaScript ``` const client = new AgentClient({ agent: "game-agent", name: "room-123", host: "your-worker.workers.dev",}); client.setState({ score: 100 });console.log(client.state); // { score: 100 } ``` TypeScript ``` const client = new AgentClient({ agent: "game-agent", name: "room-123", host: "your-worker.workers.dev",}); client.setState({ score: 100 });console.log(client.state); // { score: 100 } ``` State starts as `undefined` and is populated when the server sends the initial state on connect (from `initialState`) or when `setState()` is called. Use optional chaining (`agent.state?.field`) for safe access. The `onStateUpdate` callback continues to work as before — the new `state` property is additive. #### Idempotent `schedule()` `schedule()` now supports an `idempotent` option that deduplicates by `(type, callback, payload)`, preventing duplicate rows from accumulating when called in places that run on every Durable Object restart such as `onStart()`. **Cron schedules are idempotent by default.** Calling `schedule("0 * * * *", "tick")` multiple times with the same callback, expression, and payload returns the existing schedule row instead of creating a new one. Pass `{ idempotent: false }` to override. Delayed and date-scheduled types support opt-in idempotency: * [ JavaScript ](#tab-panel-2637) * [ TypeScript ](#tab-panel-2638) JavaScript ``` import { Agent } from "agents"; class MyAgent extends Agent { async onStart() { // Safe across restarts — only one row is created await this.schedule(60, "maintenance", undefined, { idempotent: true }); }} ``` TypeScript ``` import { Agent } from "agents"; class MyAgent extends Agent { async onStart() { // Safe across restarts — only one row is created await this.schedule(60, "maintenance", undefined, { idempotent: true }); }} ``` Two new warnings help catch common foot-guns: * Calling `schedule()` inside `onStart()` without `{ idempotent: true }` emits a `console.warn` with actionable guidance (once per callback; skipped for cron and when `idempotent` is set explicitly). * If an alarm cycle processes 10 or more stale one-shot rows for the same callback, the SDK emits a `console.warn` and a `schedule:duplicate_warning` diagnostics channel event. #### Typed `AgentClient` with `call` inference and `stub` proxy `AgentClient` now accepts an optional agent type parameter for full type inference on RPC calls, matching the typed experience already available with `useAgent`. * [ JavaScript ](#tab-panel-2641) * [ TypeScript ](#tab-panel-2642) JavaScript ``` const client = new AgentClient({ agent: "my-agent", host: window.location.host,}); // Typed call — method name autocompletes, args and return type inferredconst value = await client.call("getValue"); // Typed stub — direct RPC-style proxyawait client.stub.getValue();await client.stub.add(1, 2); ``` TypeScript ``` const client = new AgentClient({ agent: "my-agent", host: window.location.host,}); // Typed call — method name autocompletes, args and return type inferredconst value = await client.call("getValue"); // Typed stub — direct RPC-style proxyawait client.stub.getValue();await client.stub.add(1, 2); ``` State is automatically inferred from the agent type, so `onStateUpdate` is also typed: * [ JavaScript ](#tab-panel-2639) * [ TypeScript ](#tab-panel-2640) JavaScript ``` const client = new AgentClient({ agent: "my-agent", host: window.location.host, onStateUpdate: (state) => { // state is typed as MyAgent's state type },}); ``` TypeScript ``` const client = new AgentClient({ agent: "my-agent", host: window.location.host, onStateUpdate: (state) => { // state is typed as MyAgent's state type },}); ``` Existing untyped usage continues to work without changes. The RPC type utilities (`AgentMethods`, `AgentStub`, `RPCMethods`) are now exported from `agents/client` for advanced typing scenarios. `agents`, `@cloudflare/ai-chat`, and `@cloudflare/codemode` now require `zod ^4.0.0`. Zod v3 is no longer supported. #### `@cloudflare/ai-chat` fixes * **Turn serialization** — `onChatMessage()` and `_reply()` work is now queued so user requests, tool continuations, and `saveMessages()` never stream concurrently. * **Duplicate messages on stop** — Clicking stop during an active stream no longer splits the assistant message into two entries. * **Duplicate messages after tool calls** — Orphaned client IDs no longer leak into persistent storage. #### `keepAlive()` and `keepAliveWhile()` are no longer experimental `keepAlive()` now uses a lightweight in-memory ref count instead of schedule rows. Multiple concurrent callers share a single alarm cycle. The `@experimental` tag has been removed from both `keepAlive()` and `keepAliveWhile()`. #### `@cloudflare/codemode`: TanStack AI integration A new entry point `@cloudflare/codemode/tanstack-ai` adds support for [TanStack AI's ↗](https://tanstack.com/ai) `chat()` as an alternative to the Vercel AI SDK's `streamText()`: * [ JavaScript ](#tab-panel-2643) * [ TypeScript ](#tab-panel-2644) JavaScript ``` import { createCodeTool, tanstackTools,} from "@cloudflare/codemode/tanstack-ai";import { chat } from "@tanstack/ai"; const codeTool = createCodeTool({ tools: [tanstackTools(myServerTools)], executor,}); const stream = chat({ adapter, tools: [codeTool], messages }); ``` TypeScript ``` import { createCodeTool, tanstackTools } from "@cloudflare/codemode/tanstack-ai";import { chat } from "@tanstack/ai"; const codeTool = createCodeTool({ tools: [tanstackTools(myServerTools)], executor,}); const stream = chat({ adapter, tools: [codeTool], messages }); ``` #### Upgrade To update to the latest version: Terminal window ``` npm i agents@latest @cloudflare/ai-chat@latest ``` ```json {"@context":"https://schema.org","@type":"BlogPosting","@id":"https://developers.cloudflare.com/changelog/post/2026-03-23-agents-sdk-v080/#page","headline":"Agents SDK v0.8.0: readable state, idempotent schedules, typed AgentClient, and Zod 4 · Changelog","description":"Agents SDK v0.8.0 exposes a readable state property on useAgent and AgentClient, makes schedule() idempotent for cron and opt-in for other types, adds full TypeScript inference to AgentClient, and drops Zod v3 in favor of Zod v4.","url":"https://developers.cloudflare.com/changelog/post/2026-03-23-agents-sdk-v080/","inLanguage":"en","image":"https://developers.cloudflare.com/changelog-preview.png","dateModified":"2026-03-23","datePublished":"2026-03-23","publisher":{"@type":"Organization","name":"Cloudflare","url":"https://www.cloudflare.com/"},"isPartOf":{"@type":"WebSite","@id":"https://developers.cloudflare.com/#website","name":"Cloudflare Docs","url":"https://developers.cloudflare.com/"}} ```