diff --git a/src/lib/components/chat/Messages/structuredOutput.ts b/src/lib/components/chat/Messages/structuredOutput.ts
index 31f5c70bd1..b59587c374 100644
--- a/src/lib/components/chat/Messages/structuredOutput.ts
+++ b/src/lib/components/chat/Messages/structuredOutput.ts
@@ -434,6 +434,16 @@ export function buildOutputDisplayItems(output: OutputItem[] = []): OutputDispla
 	});
 
 	flushDetails();
+
+	// Providers can reuse item ids across tool-call rounds.
+	const seenIds = new Set<string>();
+	displayItems.forEach((displayItem, index) => {
+		if (seenIds.has(displayItem.id)) {
+			displayItem.id = `${displayItem.id}-${index}`;
+		}
+		seenIds.add(displayItem.id);
+	});
+
 	return displayItems;
 }