diff --git a/packages/web-ui/src/components/SandboxedIframe.ts b/packages/web-ui/src/components/SandboxedIframe.ts
index 8d9655df..47155016 100644
--- a/packages/web-ui/src/components/SandboxedIframe.ts
+++ b/packages/web-ui/src/components/SandboxedIframe.ts
@@ -329,9 +329,29 @@ export class SandboxIframe extends LitElement {
 		(async () => {
 			try {
 				${userCode}
+
+				// Call completion callbacks before complete()
+				if (window.__completionCallbacks && window.__completionCallbacks.length > 0) {
+					try {
+						await Promise.all(window.__completionCallbacks.map(cb => cb(true)));
+					} catch (e) {
+						console.error('Completion callback error:', e);
+					}
+				}
+
 				window.complete();
 			} catch (error) {
 				console.error(error?.stack || error?.message || String(error));
+
+				// Call completion callbacks before complete() (error path)
+				if (window.__completionCallbacks && window.__completionCallbacks.length > 0) {
+					try {
+						await Promise.all(window.__completionCallbacks.map(cb => cb(false)));
+					} catch (e) {
+						console.error('Completion callback error:', e);
+					}
+				}
+
 				window.complete({
 					message: error?.message || String(error),
 					stack: error?.stack || new Error().stack
diff --git a/packages/web-ui/src/components/sandbox/ConsoleRuntimeProvider.ts b/packages/web-ui/src/components/sandbox/ConsoleRuntimeProvider.ts
index 642aa15a..00ebeac2 100644
--- a/packages/web-ui/src/components/sandbox/ConsoleRuntimeProvider.ts
+++ b/packages/web-ui/src/components/sandbox/ConsoleRuntimeProvider.ts
@@ -143,15 +143,6 @@ export class ConsoleRuntimeProvider implements SandboxRuntimeProvider {
 					}
 				}
 			};
-
-			// Fallback timeout for HTML artifacts that don't call complete()
-			if (document.readyState === "complete" || document.readyState === "interactive") {
-				setTimeout(() => (window as any).complete(), 2000);
-			} else {
-				window.addEventListener("load", () => {
-					setTimeout(() => (window as any).complete(), 2000);
-				});
-			}
 		};
 	}