# Cloudflare Agents SDK [[Cloudflare]] Agents SDK is a TypeScript framework for building stateful AI agents on [[Cloudflare Workers]] and [[Cloudflare Durable Objects]]. Each agent instance maps to a single Durable Object — giving it strong consistency, persistent SQLite-backed state, WebSocket support, and the ability to schedule its own future work via alarms. The SDK is Cloudflare-specific by design: it leans on Durable Objects' per-instance addressability, Workers' V8 isolate model, and the platform's WebSocket hibernation. It is not a generic agent framework like LangChain — it is "how to write durable agents that live forever on Cloudflare's edge." ## Why It Matters Most agent frameworks treat state as an afterthought — assume external Redis, external DB, external queue. The Agents SDK inverts this: every agent has its own SQLite database inside its Durable Object, can wake up on a schedule, and resumes exactly where it left off after restarts. For long-running agents (research, monitoring, orchestration), this changes the operational model. Pairs naturally with [[Cloudflare Workers AI]] for inference (routed through [[Cloudflare AI Gateway]] if you want logs and spend limits), [[Cloudflare Sandbox SDK]] for code execution, [[Cloudflare Browser Rendering|Browser Run]] and [[KiteSurf]] for browsing, [[Cloudflare Artifacts]] for Git-backed files, [[Cloudflare Email Routing and Sending|Email Service]] for an inbox, and [[Cloudflare Vectorize]] for memory/RAG. ## Core Primitives - **Agent class**: extends Durable Object, exposes RPC methods, manages state - **State management**: typed via TypeScript generics, persisted automatically - **Scheduled tasks**: agents can call `this.schedule(when, method)` to invoke themselves later - **Real-time**: WebSocket support for streaming responses to clients - **Workflows**: durable, restartable multi-step processes via [[Cloudflare Workflows]] - **MCP servers**: ship agents as [[Model Context Protocol (MCP)|Model Context Protocol]] servers; the SDK supports the MCP 2026-07-28 specification since July 27, 2026 - **Project Think** (`@cloudflare/think`): the opinionated harness. v0.14.0 (June 2, 2026) added on-demand [[AI Agent Skills|Agent Skills]] (experimental), chat messengers starting with Telegram, declarative scheduled tasks and durable reasoning steps inside Workflows; v0.17.0 (June 26) added background sub-agents - **Third-party harnesses**: the Pi harness runs on top of the SDK through `PiHarness` (beta, October 2, 2026), Cloudflare's first step toward hosting other teams' harnesses - **Tracing**: agent traces for Think, [[Flue]] and AI SDK runs (August 4, 2026) ## Common Use Cases - **Chat agents** with persistent memory across sessions - **Voice agents** with hibernating WebSocket connections - **Browser-automation agents** orchestrating multi-step workflows - **Background workers** that wake up, do work, sleep — for hours, days, weeks - **MCP servers** exposing tools to Claude and other LLM clients ## References - Agents SDK home: https://developers.cloudflare.com/agents/ - GitHub: https://github.com/cloudflare/agents - Changelog, Agents SDK v0.14.0 (2026-06-02): https://developers.cloudflare.com/changelog/post/2026-06-02-agents-sdk-v0.14.0/ - Changelog, background sub-agents (2026-06-26): https://developers.cloudflare.com/changelog/post/2026-06-26-agents-sdk-v0.17.0/ - Changelog, MCP 2026-07-28 support (2026-07-27): https://developers.cloudflare.com/changelog/post/2026-07-27-agents-sdk-v0.20.0-mcp-sdk-v2/ - Changelog, agent tracing (2026-08-04): https://developers.cloudflare.com/changelog/post/2026-08-04-agent-tracing/ - Changelog, Pi harness (2026-10-02): https://developers.cloudflare.com/changelog/post/2026-10-02-pi-harness/ ## Related - [[Cloudflare]] - [[Cloudflare Workers]] - [[Cloudflare Durable Objects]] - [[Cloudflare Workers AI]] - [[Cloudflare Sandbox SDK]] - [[Cloudflare Vectorize]] - [[Cloudflare AI Gateway]] - [[Cloudflare Browser Rendering|Cloudflare Browser Run]] - [[KiteSurf]] - [[Cloudflare Artifacts]] - [[Cloudflare Email Routing and Sending]] - [[Cloudflare Wallets]] - [[Model Context Protocol (MCP)]] - [[Code Mode MCP Pattern]] - [[AI Agent Skills]] - [[Flue]] - [[TypeScript]] - [[Wrangler]]