diff --git a/extensions/ask-user-question/index.ts b/extensions/ask-user-question/index.ts
new file mode 100644
index 0000000..c36c8e8
--- /dev/null
+++ b/extensions/ask-user-question/index.ts
@@ -0,0 +1,641 @@
+import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
+import {
+	Editor,
+	type EditorTheme,
+	Key,
+	Text,
+	matchesKey,
+	truncateToWidth,
+	wrapTextWithAnsi,
+} from "@mariozechner/pi-tui";
+import { Type } from "typebox";
+
+interface AskOption {
+	label: string;
+	value: string;
+	description?: string;
+}
+
+interface DisplayOption extends AskOption {
+	id: string;
+	index?: number;
+	isOther?: boolean;
+	isSubmit?: boolean;
+}
+
+interface TextAnswer {
+	type: "text";
+	label: string;
+	value: string;
+}
+
+interface OptionAnswer {
+	type: "option";
+	label: string;
+	value: string;
+	index: number;
+}
+
+interface OtherAnswer {
+	type: "other";
+	label: string;
+	value: string;
+}
+
+type AskAnswer = TextAnswer | OptionAnswer | OtherAnswer;
+type AskUserQuestionStatus = "answered" | "cancelled" | "unavailable";
+type AskUserQuestionMode = "text" | "single-select" | "multi-select";
+
+interface AskUserQuestionResultDetails {
+	status: AskUserQuestionStatus;
+	question: string;
+	context?: string;
+	mode: AskUserQuestionMode;
+	answers: AskAnswer[];
+	message?: string;
+}
+
+const OptionSchema = Type.Object({
+	label: Type.String({
+		description:
+			'Display label for the option. If you recommend an option, place it first and append "(Recommended)" to the label.',
+	}),
+	value: Type.Optional(
+		Type.String({
+			description: "Optional machine-readable value returned for the option. Defaults to the label.",
+		}),
+	),
+	description: Type.Optional(Type.String({ description: "Optional extra detail shown below the option." })),
+});
+
+const AskUserQuestionParams = Type.Object({
+	question: Type.String({
+		description: "The single question to ask the user. Ask exactly one question per tool call.",
+	}),
+	details: Type.Optional(
+		Type.String({
+			description: "Optional extra context or instructions shown under the question.",
+		}),
+	),
+	options: Type.Optional(
+		Type.Array(OptionSchema, {
+			description:
+				"Optional multiple-choice options. Omit or pass an empty array for free-form text input. Users will always be able to choose Other and type a custom answer when options are provided.",
+		}),
+	),
+	multiSelect: Type.Optional(
+		Type.Boolean({
+			description: "Set to true to allow multiple answers to be selected for a question.",
+		}),
+	),
+});
+
+function normalizeOptions(options: Array<{ label: string; value?: string; description?: string }> | undefined): AskOption[] {
+	return (options || [])
+		.map((option) => ({
+			label: option.label.trim(),
+			value: option.value?.trim() || option.label.trim(),
+			description: option.description?.trim() || undefined,
+		}))
+		.filter((option) => option.label.length > 0);
+}
+
+function getOtherLabel(options: AskOption[]): string {
+	return options.some((option) => option.label.toLowerCase() === "other") ? "Other (custom)" : "Other";
+}
+
+function createEditorTheme(theme: any): EditorTheme {
+	return {
+		borderColor: (s) => theme.fg("accent", s),
+		selectList: {
+			selectedPrefix: (t) => theme.fg("accent", t),
+			selectedText: (t) => theme.fg("accent", t),
+			description: (t) => theme.fg("muted", t),
+			scrollInfo: (t) => theme.fg("dim", t),
+			noMatch: (t) => theme.fg("warning", t),
+		},
+	};
+}
+
+function addWrapped(lines: string[], text: string, width: number, indent = ""): void {
+	const contentWidth = Math.max(1, width - indent.length);
+	for (const line of wrapTextWithAnsi(text, contentWidth)) {
+		lines.push(truncateToWidth(`${indent}${line}`, width));
+	}
+}
+
+function formatAnswerForModel(answer: AskAnswer): string {
+	switch (answer.type) {
+		case "text":
+			return answer.label;
+		case "other":
+			return `Other: ${answer.label}`;
+		case "option":
+			return `${answer.index}. ${answer.label}`;
+	}
+}
+
+function answerSortRank(answer: AskAnswer): number {
+	switch (answer.type) {
+		case "option":
+			return answer.index;
+		case "other":
+			return Number.MAX_SAFE_INTEGER - 1;
+		case "text":
+			return Number.MAX_SAFE_INTEGER;
+	}
+}
+
+function sortAnswers(answers: AskAnswer[]): AskAnswer[] {
+	return [...answers].sort((a, b) => answerSortRank(a) - answerSortRank(b));
+}
+
+function buildStructuredResult(
+	status: AskUserQuestionStatus,
+	question: string,
+	mode: AskUserQuestionMode,
+	answers: AskAnswer[],
+	context?: string,
+	message?: string,
+) {
+	return {
+		status,
+		question,
+		context,
+		mode,
+		answers,
+		message,
+	} as AskUserQuestionResultDetails;
+}
+
+function cancelledResult(question: string, mode: AskUserQuestionMode, context?: string) {
+	const message = "User cancelled the question";
+	return {
+		content: [{ type: "text" as const, text: message }],
+		details: buildStructuredResult("cancelled", question, mode, [], context, message),
+	};
+}
+
+function unavailableResult(question: string, mode: AskUserQuestionMode, message: string, context?: string) {
+	return {
+		content: [{ type: "text" as const, text: message }],
+		details: buildStructuredResult("unavailable", question, mode, [], context, message),
+	};
+}
+
+function buildResult(question: string, context: string | undefined, mode: AskUserQuestionMode, answers: AskAnswer[]) {
+	let text: string;
+	if (mode === "text") {
+		const answer = answers[0];
+		text = answer.label.trim().length > 0 ? `User answered: ${answer.label}` : "User submitted an empty response";
+	} else if (mode === "single-select") {
+		text = `User selected: ${formatAnswerForModel(answers[0])}`;
+	} else {
+		text = `User selected:\n${answers.map((answer) => `- ${formatAnswerForModel(answer)}`).join("\n")}`;
+	}
+
+	return {
+		content: [{ type: "text" as const, text }],
+		details: buildStructuredResult("answered", question, mode, answers, context),
+	};
+}
+
+async function askSingleChoice(
+	ctx: any,
+	question: string,
+	context: string | undefined,
+	options: AskOption[],
+): Promise<AskAnswer | null> {
+	const otherLabel = getOtherLabel(options);
+	const allOptions: DisplayOption[] = [
+		...options.map((option, index) => ({ ...option, id: `option:${index}`, index: index + 1 })),
+		{ id: "other", label: otherLabel, value: "__other__", isOther: true },
+	];
+
+	return ctx.ui.custom<AskAnswer | null>((tui: any, theme: any, _kb: any, done: (result: AskAnswer | null) => void) => {
+		let optionIndex = 0;
+		let editMode = false;
+		let cachedLines: string[] | undefined;
+		const editor = new Editor(tui, createEditorTheme(theme));
+
+		editor.onSubmit = (value) => {
+			const trimmed = value.trim();
+			if (!trimmed) return;
+			done({ type: "other", label: trimmed, value: trimmed });
+		};
+
+		function refresh() {
+			cachedLines = undefined;
+			tui.requestRender();
+		}
+
+		function handleInput(data: string) {
+			if (editMode) {
+				if (matchesKey(data, Key.escape)) {
+					editMode = false;
+					editor.setText("");
+					refresh();
+					return;
+				}
+				editor.handleInput(data);
+				refresh();
+				return;
+			}
+
+			if (matchesKey(data, Key.up)) {
+				optionIndex = Math.max(0, optionIndex - 1);
+				refresh();
+				return;
+			}
+			if (matchesKey(data, Key.down)) {
+				optionIndex = Math.min(allOptions.length - 1, optionIndex + 1);
+				refresh();
+				return;
+			}
+			if (matchesKey(data, Key.enter)) {
+				const selected = allOptions[optionIndex];
+				if (selected.isOther) {
+					editMode = true;
+					editor.setText("");
+					refresh();
+					return;
+				}
+				done({
+					type: "option",
+					label: selected.label,
+					value: selected.value,
+					index: selected.index!,
+				});
+				return;
+			}
+			if (matchesKey(data, Key.escape)) {
+				done(null);
+			}
+		}
+
+		function render(width: number): string[] {
+			if (cachedLines) return cachedLines;
+
+			const lines: string[] = [];
+			const add = (text: string) => lines.push(truncateToWidth(text, width));
+
+			add(theme.fg("accent", "─".repeat(width)));
+			addWrapped(lines, theme.fg("text", ` ${question}`), width);
+			if (context) {
+				lines.push("");
+				addWrapped(lines, theme.fg("muted", ` ${context}`), width);
+			}
+			lines.push("");
+
+			for (let i = 0; i < allOptions.length; i++) {
+				const option = allOptions[i];
+				const selected = i === optionIndex;
+				const prefix = selected ? theme.fg("accent", "> ") : "  ";
+				const label = option.isOther ? option.label : `${option.index}. ${option.label}`;
+				const styled = selected ? theme.fg("accent", label) : theme.fg("text", label);
+				add(`${prefix}${styled}`);
+				if (option.description) {
+					addWrapped(lines, theme.fg("muted", option.description), width, "     ");
+				}
+			}
+
+			if (editMode) {
+				lines.push("");
+				add(theme.fg("muted", " Write your custom answer:"));
+				for (const line of editor.render(Math.max(1, width - 2))) {
+					add(` ${line}`);
+				}
+				lines.push("");
+				add(theme.fg("dim", " Enter to submit • Esc to go back"));
+			} else {
+				lines.push("");
+				add(theme.fg("dim", " ↑↓ navigate • Enter select • Esc cancel"));
+			}
+
+			add(theme.fg("accent", "─".repeat(width)));
+			cachedLines = lines;
+			return lines;
+		}
+
+		return {
+			render,
+			invalidate: () => {
+				cachedLines = undefined;
+			},
+			handleInput,
+		};
+	});
+}
+
+async function askMultiChoice(
+	ctx: any,
+	question: string,
+	context: string | undefined,
+	options: AskOption[],
+): Promise<AskAnswer[] | null> {
+	const otherLabel = getOtherLabel(options);
+	const choiceItems: DisplayOption[] = options.map((option, index) => ({
+		...option,
+		id: `option:${index}`,
+		index: index + 1,
+	}));
+	const submitItem: DisplayOption = { id: "submit", label: "Submit", value: "__submit__", isSubmit: true };
+	const allItems: DisplayOption[] = [
+		...choiceItems,
+		{ id: "other", label: otherLabel, value: "__other__", isOther: true },
+		submitItem,
+	];
+
+	return ctx.ui.custom<AskAnswer[] | null>((tui: any, theme: any, _kb: any, done: (result: AskAnswer[] | null) => void) => {
+		let optionIndex = 0;
+		let editMode = false;
+		let cachedLines: string[] | undefined;
+		const selected = new Map<string, AskAnswer>();
+		const editor = new Editor(tui, createEditorTheme(theme));
+
+		editor.onSubmit = (value) => {
+			const trimmed = value.trim();
+			if (!trimmed) return;
+			selected.set("other", { type: "other", label: trimmed, value: trimmed });
+			editMode = false;
+			refresh();
+		};
+
+		function refresh() {
+			cachedLines = undefined;
+			tui.requestRender();
+		}
+
+		function toggleOption(item: DisplayOption) {
+			if (selected.has(item.id)) {
+				selected.delete(item.id);
+			} else {
+				selected.set(item.id, {
+					type: "option",
+					label: item.label,
+					value: item.value,
+					index: item.index!,
+				});
+			}
+			refresh();
+		}
+
+		function handleInput(data: string) {
+			if (editMode) {
+				if (matchesKey(data, Key.escape)) {
+					editMode = false;
+					editor.setText(selected.get("other")?.label || "");
+					refresh();
+					return;
+				}
+				editor.handleInput(data);
+				refresh();
+				return;
+			}
+
+			if (matchesKey(data, Key.up)) {
+				optionIndex = Math.max(0, optionIndex - 1);
+				refresh();
+				return;
+			}
+			if (matchesKey(data, Key.down)) {
+				optionIndex = Math.min(allItems.length - 1, optionIndex + 1);
+				refresh();
+				return;
+			}
+
+			const current = allItems[optionIndex];
+			if (matchesKey(data, Key.space)) {
+				if (current.isSubmit) return;
+				if (current.isOther) {
+					if (selected.has("other")) {
+						selected.delete("other");
+						refresh();
+					} else {
+						editMode = true;
+						editor.setText("");
+						refresh();
+					}
+					return;
+				}
+				toggleOption(current);
+				return;
+			}
+
+			if (matchesKey(data, Key.enter)) {
+				if (current.isSubmit) {
+					if (selected.size > 0) {
+						done(sortAnswers(Array.from(selected.values())));
+					}
+					return;
+				}
+				if (current.isOther) {
+					editMode = true;
+					editor.setText(selected.get("other")?.label || "");
+					refresh();
+					return;
+				}
+				toggleOption(current);
+				return;
+			}
+
+			if (matchesKey(data, Key.escape)) {
+				done(null);
+			}
+		}
+
+		function render(width: number): string[] {
+			if (cachedLines) return cachedLines;
+
+			const lines: string[] = [];
+			const add = (text: string) => lines.push(truncateToWidth(text, width));
+
+			add(theme.fg("accent", "─".repeat(width)));
+			addWrapped(lines, theme.fg("text", ` ${question}`), width);
+			if (context) {
+				lines.push("");
+				addWrapped(lines, theme.fg("muted", ` ${context}`), width);
+			}
+			lines.push("");
+
+			for (let i = 0; i < allItems.length; i++) {
+				const item = allItems[i];
+				const isFocused = i === optionIndex;
+				const prefix = isFocused ? theme.fg("accent", "> ") : "  ";
+
+				if (item.isSubmit) {
+					const label = selected.size > 0 ? `✓ ${item.label} (${selected.size} selected)` : `○ ${item.label}`;
+					const styled = isFocused
+						? theme.fg("accent", label)
+						: theme.fg(selected.size > 0 ? "success" : "dim", label);
+					add(`${prefix}${styled}`);
+					continue;
+				}
+
+				if (item.isOther) {
+					const other = selected.get("other");
+					const marker = other ? "[x]" : "[ ]";
+					const suffix = other ? ` — ${other.label}` : "";
+					const styled = isFocused
+						? theme.fg("accent", `${marker} ${item.label}${suffix}`)
+						: theme.fg(other ? "success" : "text", `${marker} ${item.label}${suffix}`);
+					add(`${prefix}${styled}`);
+					continue;
+				}
+
+				const checked = selected.has(item.id);
+				const marker = checked ? "[x]" : "[ ]";
+				const label = `${marker} ${item.index}. ${item.label}`;
+				const styled = isFocused
+					? theme.fg("accent", label)
+					: theme.fg(checked ? "success" : "text", label);
+				add(`${prefix}${styled}`);
+				if (item.description) {
+					addWrapped(lines, theme.fg("muted", item.description), width, "     ");
+				}
+			}
+
+			if (editMode) {
+				lines.push("");
+				add(theme.fg("muted", " Write your custom answer:"));
+				for (const line of editor.render(Math.max(1, width - 2))) {
+					add(` ${line}`);
+				}
+				lines.push("");
+				add(theme.fg("dim", " Enter to save • Esc to go back"));
+			} else {
+				lines.push("");
+				if (selected.size === 0) {
+					add(theme.fg("warning", " Select at least one answer before submitting."));
+				}
+				add(theme.fg("dim", " ↑↓ navigate • Space toggle • Enter edit/submit • Esc cancel"));
+			}
+
+			add(theme.fg("accent", "─".repeat(width)));
+			cachedLines = lines;
+			return lines;
+		}
+
+		return {
+			render,
+			invalidate: () => {
+				cachedLines = undefined;
+			},
+			handleInput,
+		};
+	});
+}
+
+// Mutex to serialize concurrent UI interactions.
+// showExtensionCustom/editor can only handle one active call at a time.
+let uiLock: Promise<void> = Promise.resolve();
+
+function withUILock<T>(fn: () => Promise<T>): Promise<T> {
+	const prev = uiLock;
+	let release: () => void;
+	uiLock = new Promise<void>((r) => { release = r; });
+	return prev.then(fn).finally(() => release!());
+}
+
+export default function askUserQuestion(pi: ExtensionAPI) {
+	pi.registerTool({
+		name: "ask_user_question",
+		label: "ask_user_question",
+		description:
+			"Ask the user a single question and pause execution until they answer. Use this when requirements are ambiguous, user preferences are needed, a decision would materially affect implementation, or you need confirmation before proceeding. Ask exactly one question per tool call, and prefer multiple separate tool calls over bundling unrelated questions together.",
+		promptSnippet:
+			"Use this tool to ask exactly one clarifying question, missing-requirement question, preference question, or decision question before continuing.",
+		promptGuidelines: [
+			"Ask exactly one question per tool call.",
+			"If you need answers to multiple questions, make multiple separate ask_user_question tool calls instead of combining them into one prompt.",
+			'Users will always be able to select "Other" to provide custom text input when options are provided.',
+			"Use multiSelect: true only when you need multiple answers to the same question.",
+			'If you recommend a specific option, make it the first option in the list and add "(Recommended)" at the end of the label.',
+			"Prefer this tool over guessing when requirements, preferences, or implementation choices are unclear.",
+			"Use this tool when multiple valid implementation paths exist and the preferred path depends on user choice.",
+		],
+		parameters: AskUserQuestionParams,
+
+		async execute(_toolCallId, params, signal, _onUpdate, ctx) {
+			const options = normalizeOptions(params.options);
+			const context = params.details?.trim() || undefined;
+			const mode: AskUserQuestionMode = options.length === 0 ? "text" : params.multiSelect ? "multi-select" : "single-select";
+
+			if (signal?.aborted) {
+				return cancelledResult(params.question, mode, context);
+			}
+
+			if (!ctx.hasUI) {
+				return unavailableResult(params.question, mode, "ask_user_question requires interactive mode UI", context);
+			}
+
+			return withUILock(async () => {
+				if (mode === "text") {
+					const editorTitle = context ? `${params.question}\n\n${context}` : params.question;
+					const answer = await ctx.ui.editor(editorTitle);
+					if (answer === undefined) {
+						return cancelledResult(params.question, mode, context);
+					}
+					return buildResult(params.question, context, mode, [
+						{ type: "text", label: answer.trim(), value: answer.trim() },
+					]);
+				}
+
+				if (mode === "single-select") {
+					const answer = await askSingleChoice(ctx, params.question, context, options);
+					if (!answer) {
+						return cancelledResult(params.question, mode, context);
+					}
+					return buildResult(params.question, context, mode, [answer]);
+				}
+
+				const answers = await askMultiChoice(ctx, params.question, context, options);
+				if (!answers) {
+					return cancelledResult(params.question, mode, context);
+				}
+				return buildResult(params.question, context, mode, answers);
+			});
+		},
+
+		renderCall(args, theme) {
+			const options = normalizeOptions(args.options as Array<{ label: string; value?: string; description?: string }> | undefined);
+			let text = theme.fg("toolTitle", theme.bold("ask_user_question ")) + theme.fg("muted", args.question);
+			if (args.multiSelect) {
+				text += theme.fg("dim", " [multi-select]");
+			}
+			if (options.length > 0) {
+				const labels = [...options.map((option) => option.label), getOtherLabel(options)].join(", ");
+				text += `\n${theme.fg("dim", `  Options: ${labels}`)}`;
+			}
+			return new Text(text, 0, 0);
+		},
+
+		renderResult(result, _options, theme) {
+			const details = result.details as AskUserQuestionResultDetails | undefined;
+			if (!details) {
+				const first = result.content[0];
+				return new Text(first?.type === "text" ? first.text : "", 0, 0);
+			}
+
+			if (details.status === "cancelled") {
+				return new Text(theme.fg("warning", details.message || "Cancelled"), 0, 0);
+			}
+
+			if (details.status === "unavailable") {
+				return new Text(theme.fg("warning", details.message || "ask_user_question unavailable"), 0, 0);
+			}
+
+			const lines = details.answers.map((answer) => {
+				switch (answer.type) {
+					case "text":
+						return `${theme.fg("success", "✓ ")}${theme.fg("accent", answer.label || "(empty response)")}`;
+					case "other":
+						return `${theme.fg("success", "✓ ")}${theme.fg("muted", "Other: ")}${theme.fg("accent", answer.label)}`;
+					case "option":
+						return `${theme.fg("success", "✓ ")}${theme.fg("accent", `${answer.index}. ${answer.label}`)}`;
+				}
+			});
+			return new Text(lines.join("\n"), 0, 0);
+		},
+	});
+}