/** * The host call that says "the artifact is on screen now". * * ## Why a host needs to be told * * Opening an artifact is a three-document journey — the console fetches the * row, loads the shell document into an iframe, and the shell compiles the JSX * into a further nested frame. A host that wants to hold ONE loading surface * across all of it (the console does; see `ArtifactStageSkeleton`) needs to know * when the last of those has actually painted, and nothing in the MCP-Apps * protocol says so. `ui/notifications/size-changed` is the closest thing and it * is not the same fact: the shell document reports its own size while it is * still booting, long before any artifact exists, and a fill-mode host ignores * the report entirely. * * So the shell says it explicitly, once, when it has something to show. * * ## "Rendered" means presented, not successful * * The signal fires for the ERROR surfaces too — a compile failure, a component * that threw, an artifact that rendered fine. All three are "the shell is done * waiting and the user should be looking at the frame rather than a skeleton", * which is the only question the host is asking. A signal that fired only on * success would strand a failed artifact under a loading state forever, which is * a worse bug than the one this exists to fix. * * ## Why this is its own module * * Same reason as `./preview-capture`, and it is a hard constraint rather than a * preference: `shell-app.tsx` imports `virtual:executor-tailwind-browser` and * `virtual:executor-inner-renderer`, which exist only inside the standalone * shell's own Vite build. Importing a constant FROM there drags those virtual * modules into the console's bundle, where nothing supplies them, and the * artifact renderer then fails to load at all. A module with no imports of its * own is what lets both halves agree on the vocabulary. * * ## Why it rides `callServerTool` * * Because that seam already exists in every host, exactly as the preview capture * does. The console intercepts the name before the tool transport, so it never * reaches `/executions` — a "you can stop waiting now" is not an execution and * must not be metered, approved or logged as one. */export const ARTIFACT_RENDERED_TOOL = "executor-artifact-rendered"; /** * The host-context key by which a host asks to be told. * * Carried on `McpUiHostContext`'s open index signature, the spec's own * forward-compatibility seam — the same door `PREVIEW_CAPTURE_HOST_CONTEXT_KEY` * goes through. Only the console sets it, because only the console holds a * loading surface it needs to take down. Every real MCP client omits it and the * shell never makes the call, so no host is sent a tool name it has never heard * of. * * A separate key from the preview capture rather than one "this is the console" * flag: they are two independent capabilities, and a host that wants a seamless * handoff without storing thumbnails should be able to say exactly that. */export const RENDER_SIGNAL_HOST_CONTEXT_KEY = "executorRenderSignal";