Fix "tool undefined completed" accessibility announcement in chat (#251442)

Author: Copilot

src/vs/workbench/contrib/chat/browser/chatAccessibilityProvider.ts

@@ -88,7 +88,17 @@ export class ChatAccessibilityProvider implements IListAccessibilityProvider<Cha
 				toolInvocationHint = this._instantiationService.invokeFunction(getToolConfirmationAlert, toolInvocation);
 			} else { // all completed
 				for (const invocation of toolInvocation) {
-					toolInvocationHint += localize('toolCompletedHint', "Tool {0} completed.", typeof invocation.confirmationMessages?.title === 'string' ? invocation.confirmationMessages?.title : invocation.confirmationMessages?.title.value);
+					const titleObj = invocation.confirmationMessages?.title;
+					let title = '';
+					if (typeof titleObj === 'string' && titleObj.trim()) {
+						title = titleObj;
+					} else if (titleObj && typeof titleObj === 'object' && 'value' in titleObj && titleObj.value && titleObj.value.trim()) {
+						title = titleObj.value;
+					} else {
+						// Fallback to toolId if no valid title
+						title = invocation.toolId;
+					}
+					toolInvocationHint += localize('toolCompletedHint', "Tool {0} completed.", title);
 				}
 			}
 		}