Cloudflare just opened the Agents SDK to any framework — here's what Flue brings to the runtime

Cloudflare announced yesterday that the Agents SDK is now a runtime any agent framework can build on. Flue is the first third-party framework to target it, and the Cloudflare One stack just shipped a library of agent skills for Zero Trust deployment.

This is a different kind of move than the platform announcements we've covered. Cloudflare isn't shipping a new model or a new capability. They're opening the SDK primitives so that any framework — LangGraph, CrewAI, whatever comes next — can run on Workers with the same durability guarantees, the same session state, the same tool invocation layer.

Flue is the first framework to ship on top of it. It's a Python library that gives you streaming responses, tool calls, and structured outputs with typed return values. The example code in the post shows a weather agent that calls OpenWeatherMap, returns structured JSON, and streams the response back to the client. All of that runs on Workers, billed per invocation, not per hour.

What the SDK actually provides

The SDK gives you three primitives: sessions, tools, and streaming. Sessions persist across requests so the agent doesn't lose context when the user closes the tab. Tools are first-class — you define them once, Cloudflare handles the invocation loop. Streaming is built in; you don't patch it on afterward.

The Flue example defines a tool with a Python decorator, the SDK handles the rest. When the agent calls get_weather, Cloudflare invokes the function, returns the result to the model, and streams the final response. No manual loop, no hand-rolled retry logic.

Cloudflare also shipped session analytics in the dashboard. You can see how many tool calls an agent made, how long each session ran, and where it failed. That's the kind of observability you need when you're running agents in production, not just in a demo.

The One stack: deployment as a skill

The second announcement is the Cloudflare One stack. It's a library of agent skills that teach any AI agent how to plan, deploy, and manage a Zero Trust environment. The skills cover device enrollment, network routing, DNS filtering, and security policies. An agent trained on the One stack can provision a new office location or onboard a remote team without a migration call.

The post includes an example where an agent configures a new branch office. The agent reads the One stack docs, figures out the required policies, deploys the Cloudflare Tunnel, and sets up DNS routing. No human in the loop until the final approval.

This is the pattern we've been seeing more of: platforms shipping not just APIs but agent-native documentation. Stripe did it with Projects, Vercel did it with deployment skills, now Cloudflare is doing it for Zero Trust. The documentation itself becomes executable by an agent.

What this means for frameworks

If you're building on LangGraph or CrewAI today, you deploy to a long-running server or a serverless function with cold start penalties. Cloudflare is offering a different model: your framework runs on Workers, sessions persist in Durable Objects, and you pay per invocation. The SDK handles the infrastructure; you write the agent logic.

Flue is the proof of concept. It's not the only framework that will target the SDK. Cloudflare's bet is that once the primitives are open, other frameworks will follow. If that happens, Workers becomes the default runtime for agentic workloads the same way it became the default for edge functions.

The One stack is the second piece. Cloudflare is betting that agents will replace GUIs for infrastructure tasks, and the way to win that transition is to ship documentation that agents can execute. If your platform doesn't have an agent-native docs layer, your competitor will.

We've deployed agents on Cloudflare Workers before — Goldie runs on the edge, handles 200+ calls a day, and hasn't had a cold start issue since we migrated from Retell. The SDK opening up means we can use the same runtime for internal tooling agents that need session state and structured outputs. That's useful.

Cloudflare is positioning Workers as the runtime for agents, not just web apps. The SDK opening is the first step. The One stack is the second. Watch for more frameworks to target it.