Cloudflare Agents separates infrastructure from behavior: the SDK runs persistent instances, a harness drives the model/tool loop, channels receive events, and tools perform actions. You can choose Think, write your own loop, or use beta PiHarness.

Cloudflare Agents is a TypeScript/JavaScript SDK for building agents on Cloudflare. Its documentation separates four parts:

Part	Responsibility	Examples
Runtime	Agent identity, persistent state, connections and scheduling	The Agent class on Durable Objects
Harness	Prompt construction, model calls, tool selection and continuation	Your own loop, Think, or beta PiHarness
Channels	Deliver user messages and system events	Web chat, voice, email, Slack and webhooks
Tools	Perform actions and retrieve information	MCP, browser automation, Sandbox and AI Search

Think supplies a chat loop with saved messages, streaming, client tools and stream resumption. You extend its base class and select a model. For a custom loop, you can use the lower-level runtime directly.

Model inference is accessed separately. The SDK supports Workers AI and external providers such as OpenAI, Anthropic and Gemini. Changing the model provider is separate from changing the hosting runtime, which uses Cloudflare Durable Objects.

Cloudflare also documents a beta Pi Durable integration. See the update to our Pi investigation.

This is a documentation overview checked on October 3, 2026. We have not deployed or tested an agent here.

Sources: Agents overview, harness choices, Think, model providers.