OP here. I work with Mike on the SDK, and he covered why we built it, so here's how it actually works.

We treat "channel" as one layer with four pieces:

Adapters normalize each platform's webhooks and quirks into a single neutral event shape.

Ops owns delivery, ordering and reconnects. The run loop is ack-first: post the approval card, ack the delivery, and resume the run when the click arrives. That's the reason approvals survive retries and process restarts instead of stranding a half-finished run.

Rendering is a virtual DOM for chat. JSX compiles to native Block Kit or Adaptive Cards. Handler IDs are content hashes rather than generated per deploy, so buttons posted last week still resolve after you ship.

On top of that a small API: createChannel, threads, tools, approvals.

Diagram of the open-source path, since that question came up elsewhere in the thread: https://github.com/CopilotKit/channels-sdk/blob/main/assets/...

One thing worth being precise about, since licensing is the top comment. Intelligence is the backend layer: rich threads (AG-UI), memory, learning, analytics, governance. It is self-hosted and it does not call out anywhere. And CopilotKit is not an agent. We don't make model calls; your agent does, in your infrastructure, against whatever provider you already use.