feat: harden ask tool validation and fallback

src/schema.ts

@@ -2,19 +2,23 @@ import { Type } from "@sinclair/typebox";
 
 export const AskOptionSchema = Type.Object({
 	value: Type.String({
+		minLength: 1,
 		description:
 			"Machine-readable value returned for this option in the result",
 	}),
 	label: Type.String({
+		minLength: 1,
 		description: "Short visible option label shown in the list",
 	}),
 	description: Type.Optional(
 		Type.String({
+			minLength: 1,
 			description: "Optional one-line explanation to help the user choose",
 		})
 	),
 	preview: Type.Optional(
 		Type.String({
+			minLength: 1,
 			description:
 				"Optional preview content shown in the dedicated preview pane for preview questions",
 		})
@@ -23,15 +27,18 @@ export const AskOptionSchema = Type.Object({
 
 export const AskQuestionSchema = Type.Object({
 	id: Type.String({
+		minLength: 1,
 		description:
 			"Stable question identifier used as the key in returned answers",
 	}),
 	label: Type.Optional(
 		Type.String({
+			minLength: 1,
 			description: "Short tab label, e.g. Goal, Audience, Tone, Scope",
 		})
 	),
 	prompt: Type.String({
+		minLength: 1,
 		description:
 			"Direct question shown to the user; ask about one decision at a time",
 	}),
@@ -51,6 +58,7 @@ export const AskQuestionSchema = Type.Object({
 		})
 	),
 	options: Type.Array(AskOptionSchema, {
+		minItems: 1,
 		description: "Answer options; prefer 2-4 clear choices when possible",
 	}),
 });
@@ -58,11 +66,13 @@ export const AskQuestionSchema = Type.Object({
 export const AskParamsSchema = Type.Object({
 	title: Type.Optional(
 		Type.String({
+			minLength: 1,
 			description:
 				"Optional short title shown above the clarification flow, e.g. README direction",
 		})
 	),
 	questions: Type.Array(AskQuestionSchema, {
+		minItems: 1,
 		description: "Questions to ask in the interactive clarification flow",
 	}),
 });