diff --git a/packages/coding-agent/src/extensibility/extensions/types.ts b/packages/coding-agent/src/extensibility/extensions/types.ts
index 59b67e3b9..aa2f0764e 100644
--- a/packages/coding-agent/src/extensibility/extensions/types.ts
+++ b/packages/coding-agent/src/extensibility/extensions/types.ts
@@ -125,6 +125,8 @@ export interface ExtensionUIDialogOptions {
 	timeout?: number;
 	/** Invoked when the UI times out while waiting for a selection/input */
 	onTimeout?: () => void;
+	/** Invoked when the UI-managed timeout countdown starts */
+	onTimeoutStart?: () => void;
 	/** Invoked when user input resets a UI-managed timeout countdown */
 	onTimeoutReset?: () => void;
 	/** Initial cursor position for select dialogs (0-indexed) */
diff --git a/packages/coding-agent/src/modes/components/hook-selector.ts b/packages/coding-agent/src/modes/components/hook-selector.ts
index f5e5570b3..3165166ae 100644
--- a/packages/coding-agent/src/modes/components/hook-selector.ts
+++ b/packages/coding-agent/src/modes/components/hook-selector.ts
@@ -61,6 +61,7 @@ export interface HookSelectorOptions {
 	tui?: TUI;
 	timeout?: number;
 	onTimeout?: () => void;
+	onTimeoutStart?: () => void;
 	onTimeoutReset?: () => void;
 	initialIndex?: number;
 	outline?: boolean;
@@ -235,6 +236,7 @@ export class HookSelectorComponent extends Container {
 		}
 
 		if (opts?.timeout && opts.timeout > 0 && opts.tui) {
+			opts.onTimeoutStart?.();
 			this.#countdown = new CountdownTimer(
 				opts.timeout,
 				opts.tui,
diff --git a/packages/coding-agent/src/modes/controllers/extension-ui-controller.ts b/packages/coding-agent/src/modes/controllers/extension-ui-controller.ts
index ef27b3644..f21932721 100644
--- a/packages/coding-agent/src/modes/controllers/extension-ui-controller.ts
+++ b/packages/coding-agent/src/modes/controllers/extension-ui-controller.ts
@@ -624,6 +624,7 @@ export class ExtensionUiController {
 					initialIndex: dialogOptions?.initialIndex,
 					timeout: dialogOptions?.timeout,
 					onTimeout: dialogOptions?.onTimeout,
+					onTimeoutStart: dialogOptions?.onTimeoutStart,
 					onTimeoutReset: dialogOptions?.onTimeoutReset,
 					tui: this.ctx.ui,
 					outline: dialogOptions?.outline,
diff --git a/packages/coding-agent/src/tools/ask.ts b/packages/coding-agent/src/tools/ask.ts
index 15fdc8994..105284b38 100644
--- a/packages/coding-agent/src/tools/ask.ts
+++ b/packages/coding-agent/src/tools/ask.ts
@@ -389,6 +389,7 @@ interface UIContext {
 			signal?: AbortSignal;
 			outline?: boolean;
 			onTimeout?: () => void;
+			onTimeoutStart?: () => void;
 			onTimeoutReset?: () => void;
 			onLeft?: () => void;
 			onRight?: () => void;
@@ -455,6 +456,7 @@ async function askSingleQuestion(
 			signal: dialogSignal,
 			outline: true,
 			onTimeout,
+			onTimeoutStart: timeoutMs === undefined ? undefined : () => armFallbackTimeout(timeoutMs),
 			onTimeoutReset: timeoutMs === undefined ? undefined : () => armFallbackTimeout(timeoutMs),
 			helpText,
 			selectionMarker: marker?.selectionMarker,
@@ -471,9 +473,6 @@ async function askSingleQuestion(
 					}
 				: undefined,
 		};
-		if (timeoutMs !== undefined) {
-			armFallbackTimeout(timeoutMs);
-		}
 		try {
 			const choice = dialogSignal
 				? await untilAborted(dialogSignal, () => ui.select(prompt, optionsToShow, dialogOptions))
diff --git a/packages/coding-agent/test/ask-timeout.test.ts b/packages/coding-agent/test/ask-timeout.test.ts
index 34a153207..be8e2ba8b 100644
--- a/packages/coding-agent/test/ask-timeout.test.ts
+++ b/packages/coding-agent/test/ask-timeout.test.ts
@@ -48,7 +48,10 @@ describe("AskTool timeout", () => {
 
 	it("auto-selects the recommended option when the selector does not settle", async () => {
 		vi.useFakeTimers();
-		const select = vi.fn<AskSelect>(() => new Promise<string | undefined>(() => {}));
+		const select = vi.fn<AskSelect>((_title, _options, dialogOptions) => {
+			dialogOptions?.onTimeoutStart?.();
+			return new Promise<string | undefined>(() => {});
+		});
 		const abort = vi.fn();
 		const context = {
 			hasUI: true,
@@ -101,6 +104,7 @@ describe("AskTool timeout", () => {
 		vi.useFakeTimers();
 		let resetTimeout: (() => void) | undefined;
 		const select = vi.fn<AskSelect>((_title, _options, dialogOptions) => {
+			dialogOptions?.onTimeoutStart?.();
 			resetTimeout = dialogOptions?.onTimeoutReset;
 			return new Promise<string | undefined>(() => {});
 		});
@@ -161,17 +165,83 @@ describe("AskTool timeout", () => {
 		expect(abort).not.toHaveBeenCalled();
 	});
 
-	it("notifies callers when selector input resets the UI countdown", () => {
+	it("does not run the fallback timeout while the selector is queued", async () => {
 		vi.useFakeTimers();
+		let startTimeout: (() => void) | undefined;
+		const select = vi.fn<AskSelect>((_title, _options, dialogOptions) => {
+			startTimeout = dialogOptions?.onTimeoutStart;
+			return new Promise<string | undefined>(() => {});
+		});
+		const abort = vi.fn();
+		const context = {
+			hasUI: true,
+			ui: {
+				select,
+				editor: vi.fn(),
+			},
+			abort,
+		} as unknown as AgentToolContext;
+		let result: AskExecutionResult | undefined;
+		let rejection: unknown;
+
+		void createAskTool()
+			.execute(
+				"ask-timeout",
+				{
+					questions: [
+						{
+							id: "db",
+							question: "Which database?",
+							options: [{ label: "SQLite" }, { label: "Postgres" }],
+							recommended: 1,
+						},
+					],
+				},
+				undefined,
+				undefined,
+				context,
+			)
+			.then(
+				value => {
+					result = value;
+				},
+				error => {
+					rejection = error;
+				},
+			);
+
+		await drainMicrotasks();
+		expect(startTimeout).toBeDefined();
+
+		vi.advanceTimersByTime(10);
+		await drainMicrotasks();
+
+		expect(result).toBeUndefined();
+
+		startTimeout?.();
+		vi.advanceTimersByTime(10);
+		await drainMicrotasks();
+
+		expect(rejection).toBeUndefined();
+		expect(result?.details?.selectedOptions).toEqual(["Postgres"]);
+		expect(result?.details?.timedOut).toBe(true);
+		expect(abort).not.toHaveBeenCalled();
+	});
+
+	it("notifies callers when the selector countdown starts and resets", () => {
+		vi.useFakeTimers();
+		const onTimeoutStart = vi.fn();
 		const onTimeoutReset = vi.fn();
 		const selector = new HookSelectorComponent("Pick one", ["SQLite", "Postgres"], vi.fn(), vi.fn(), {
 			timeout: 10,
 			tui: { requestRender: vi.fn() } as unknown as TUI,
+			onTimeoutStart,
 			onTimeoutReset,
 		});
 
 		selector.handleInput("j");
 
+		expect(onTimeoutStart).toHaveBeenCalledTimes(1);
 		expect(onTimeoutReset).toHaveBeenCalledTimes(1);
 		selector.dispose();
 	});