diff --git a/packages/coding-agent/test/suite/regressions/4167-thinking-toggle-pending-tool-render.test.ts b/packages/coding-agent/test/suite/regressions/4167-thinking-toggle-pending-tool-render.test.ts
index 42e5546b4..8d1c2dab0 100644
--- a/packages/coding-agent/test/suite/regressions/4167-thinking-toggle-pending-tool-render.test.ts
+++ b/packages/coding-agent/test/suite/regressions/4167-thinking-toggle-pending-tool-render.test.ts
@@ -49,6 +49,7 @@ type RenderSessionContextThis = {
 	isInitialized: boolean;
 	updateEditorBorderColor(): void;
 	getRegisteredToolDefinition(toolName: string): undefined;
+	maybeShowAssistantDiagnostics(message: AssistantMessage): void;
 	addMessageToChat(message: AgentMessage, options?: { populateHistory?: boolean }): void;
 	renderSessionItems: RenderSessionItems;
 };
@@ -79,6 +80,7 @@ function createFakeInteractiveModeThis(): RenderSessionContextThis {
 		isInitialized: true,
 		updateEditorBorderColor: vi.fn(),
 		getRegisteredToolDefinition: (_toolName: string) => undefined,
+		maybeShowAssistantDiagnostics: vi.fn(),
 		renderSessionItems: (InteractiveMode.prototype as unknown as { renderSessionItems: RenderSessionItems })
 			.renderSessionItems,
 		addMessageToChat(message: AgentMessage) {