Keep the core boundary

Adapters should render SessionView and forward user intent. They should not parse SSE lines, validate DTOs, fold history, or invent a second reconnect algorithm. The framework-neutral SessionClient and its Client SDK remain the primary boundary.

type RenderAdapter = {
  mount(root: HTMLElement, sessionId: string): () => void;
};

function mountSession(adapter: RenderAdapter, root: HTMLElement, id: string) {
  const dispose = adapter.mount(root, id);
  return () => dispose();
}

Choose Vanilla DOM when a small page can use data attributes and a direct cleanup function. Choose Svelte 5 when $state fields and component lifecycle make the view easier to compose.

Compare lifecycle ownership

The vanilla example owns event listeners and returns one teardown function. The Svelte wrapper owns a long-running $state subscription with start() and stop(). Both delegate to the same transport, SseFrameParser, fold, and joinSessionView contracts.

Adapter	State boundary	Start	Stop
Vanilla DOM	`SessionView` callback	`SessionClient.connect`	returned disconnect function
Svelte 5	`LiveSessionViewStore.view`	`store.start()`	`store.stop()`

Source

The ordinary DOM binding is shown in sdk/core/examples/vanilla-session.ts. The Svelte package barrel exposes its reactive wrappers from sdk/svelte/src/index.ts.

Proof

The two exports demonstrate that adapters are thin lifecycle and rendering layers over the framework-neutral core. Continue to Embedding when the adapter is part of a static app served by Go.