diff --git a/src/auto-reply/reply/commands-plan.test.ts b/src/auto-reply/reply/commands-plan.test.ts
index ed00bb908..dfd4e9f6f 100644
--- a/src/auto-reply/reply/commands-plan.test.ts
+++ b/src/auto-reply/reply/commands-plan.test.ts
@@ -14,18 +14,21 @@ const clackHoisted = vi.hoisted(() => {
   let selectCalls = 0;
   const select = vi.fn(async ({ options, message }: any) => {
     selectCalls += 1;
-    // First: choose a section (pick first).
     if (String(message).includes("Choose a section")) {
+      // First time: choose first section, second time: review.
       if (selectCalls > 1) return "__review";
       return options[0].value;
     }
-    // Second: action selection etc.
     return options[0].value;
   });
+  const multiselect = vi.fn(async ({ options }: any) => {
+    // pick all
+    return options.map((o: any) => o.value);
+  });
   const text = vi.fn(async ({ initialValue }: any) => initialValue ?? "");
   const confirm = vi.fn(async () => true);
   const isCancel = vi.fn((v: any) => v === Symbol.for("clack:cancel"));
-  return { select, text, confirm, isCancel };
+  return { select, multiselect, text, confirm, isCancel };
 });
 
 vi.mock("@clack/prompts", async () => {
@@ -33,12 +36,16 @@ vi.mock("@clack/prompts", async () => {
     confirm: clackHoisted.confirm,
     isCancel: clackHoisted.isCancel,
     select: clackHoisted.select,
+    multiselect: clackHoisted.multiselect,
     text: clackHoisted.text,
   };
 });
 
 const hoisted = vi.hoisted(() => {
+  let calls = 0;
   const runEmbeddedPiAgent = vi.fn(async ({ prompt }: any) => {
+    calls += 1;
+
     if (String(prompt).includes("Generate a compact questionnaire")) {
       return {
         payloads: [
@@ -67,6 +74,29 @@ const hoisted = vi.hoisted(() => {
       };
     }
 
+    // Extend prompt should return one multiselect question.
+    if (String(prompt).includes("propose any missing high-signal questions")) {
+      return {
+        payloads: [
+          {
+            text: JSON.stringify({
+              goal: "demo",
+              questions: [
+                {
+                  id: "transport",
+                  section: "Constraints",
+                  prompt: "Preferred transport?",
+                  kind: "multiselect",
+                  required: true,
+                  options: ["Car", "Plane"],
+                },
+              ],
+            }),
+          },
+        ],
+      };
+    }
+
     return {
       payloads: [{ text: JSON.stringify({ ok: true }) }],
     };
diff --git a/src/auto-reply/reply/commands-plan.ts b/src/auto-reply/reply/commands-plan.ts
index 18853a3ed..ec8e8417a 100644
--- a/src/auto-reply/reply/commands-plan.ts
+++ b/src/auto-reply/reply/commands-plan.ts
@@ -1,7 +1,7 @@
 import fs from "node:fs/promises";
 import path from "node:path";
 
-import { confirm, isCancel, select, text } from "@clack/prompts";
+import { confirm, isCancel, select, text, multiselect } from "@clack/prompts";
 
 import type { ClawdbotPluginApi } from "../../plugins/types.js";
 import type { CommandHandler } from "./commands-types.js";
@@ -99,7 +99,21 @@ function buildLlmQuestionPrompt(goal: string) {
     `- Ask only high-signal questions. Prefer multiple choice when the user can pick from common options.\n` +
     `- Use sections like Goals, Constraints, Inputs, Outputs, Timeline, Risks (as appropriate).\n` +
     `- Keep it to ~8-15 questions unless the goal clearly needs more.\n` +
-    `- Use stable ids (snake_case).\n\n` +
+    `- Use stable ids (snake_case).\n` +
+    `- Use multiselect when multiple options may apply.\n\n` +
+    `GOAL:\n${goal}`
+  );
+}
+
+function buildLlmExtendPrompt(goal: string) {
+  return (
+    `You are helping a user plan a project.\n` +
+    `Given the current answers and existing question ids, propose any missing high-signal questions.\n` +
+    `Return JSON matching the provided schema.\n\n` +
+    `Rules:\n` +
+    `- If nothing important is missing, return {"goal": <same>, "questions": []}.\n` +
+    `- Do not repeat existing question ids.\n` +
+    `- Keep it short: up to 5 additional questions.\n\n` +
     `GOAL:\n${goal}`
   );
 }
@@ -231,7 +245,9 @@ export const handlePlanCommand: CommandHandler = async (params, allowTextCommand
   });
 
   const questionSet = (llmResult as any).details?.json as QuestionSet;
-  const questions = Array.isArray(questionSet?.questions) ? questionSet.questions : [];
+  const questions: QuestionSpec[] = Array.isArray(questionSet?.questions)
+    ? questionSet.questions
+    : [];
   if (questions.length === 0) {
     return {
       shouldContinue: false,
@@ -239,6 +255,9 @@ export const handlePlanCommand: CommandHandler = async (params, allowTextCommand
     };
   }
 
+  const questionsPath = path.join(planDir, "questions.json");
+  await writeJson(questionsPath, { goal, questions });
+
   // Group by section.
   const sectionOrder: string[] = [];
   const bySection = new Map<string, QuestionSpec[]>();
@@ -294,22 +313,35 @@ export const handlePlanCommand: CommandHandler = async (params, allowTextCommand
           answers[q.id] = res;
         }
       } else if (q.kind === "multiselect") {
-        // clack multiselect isn't currently imported here to keep deps minimal in this handler.
-        // Fallback to freeform comma-separated input.
-        const res = await text({
-          message: `${q.prompt} (comma-separated)`,
-          initialValue: Array.isArray(existing) ? existing.join(", ") : "",
-          placeholder: q.placeholder,
-        });
-        if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
-        const arr = String(res)
-          .split(",")
-          .map((s) => s.trim())
-          .filter(Boolean);
-        if (required && arr.length === 0) {
-          return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+        const opts = (q.options ?? []).map((o) => ({ label: o, value: o }));
+        if (opts.length === 0) {
+          const res = await text({
+            message: q.prompt,
+            initialValue: Array.isArray(existing) ? existing.join(", ") : "",
+            placeholder: q.placeholder,
+          });
+          if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+          const arr = String(res)
+            .split(",")
+            .map((s) => s.trim())
+            .filter(Boolean);
+          if (required && arr.length === 0) {
+            return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+          }
+          answers[q.id] = arr;
+        } else {
+          const res = await multiselect({
+            message: q.prompt,
+            options: opts,
+            required: required ? true : false,
+          } as any);
+          if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+          const arr = Array.isArray(res) ? res : [];
+          if (required && arr.length === 0) {
+            return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+          }
+          answers[q.id] = arr;
         }
-        answers[q.id] = arr;
       } else {
         const res = await text({
           message: q.prompt,
@@ -328,6 +360,115 @@ export const handlePlanCommand: CommandHandler = async (params, allowTextCommand
     }
   }
 
+  // One-time dynamic extension at the end.
+  const existingIds = new Set(questions.map((q) => q.id));
+  const extend = await tool.execute("llm-task", {
+    prompt: buildLlmExtendPrompt(goal),
+    input: {
+      goal,
+      answers,
+      existingQuestionIds: Array.from(existingIds),
+    },
+    schema: QUESTIONS_SCHEMA,
+  });
+
+  const extendSet = (extend as any).details?.json as QuestionSet;
+  const extraQuestions: QuestionSpec[] = Array.isArray(extendSet?.questions)
+    ? extendSet.questions
+    : [];
+  const filteredExtras = extraQuestions.filter((q) => q && q.id && !existingIds.has(q.id));
+
+  if (filteredExtras.length > 0) {
+    const ok = await confirm({
+      message: `I have ${filteredExtras.length} more question(s) to tighten the plan. Add them?`,
+    });
+    if (!isCancel(ok) && ok === true) {
+      for (const q of filteredExtras) {
+        const section = q.section?.trim() || "General";
+        if (!bySection.has(section)) {
+          sectionOrder.push(section);
+          bySection.set(section, []);
+        }
+        bySection.get(section)!.push(q);
+        questions.push(q);
+        existingIds.add(q.id);
+      }
+
+      // Ask only the newly added questions (once).
+      for (const q of filteredExtras) {
+        const existing = answers[q.id];
+        const required = Boolean(q.required);
+
+        if (q.kind === "confirm") {
+          const res = await confirm({
+            message: q.prompt,
+            initialValue: Boolean(existing ?? false),
+          });
+          if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+          answers[q.id] = Boolean(res);
+        } else if (q.kind === "select") {
+          const opts = (q.options ?? []).map((o) => ({ label: o, value: o }));
+          if (opts.length === 0) {
+            const res = await text({
+              message: q.prompt,
+              initialValue: existing ? String(existing) : "",
+            });
+            if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+            const v = String(res).trim();
+            if (required && !v)
+              return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+            answers[q.id] = v;
+          } else {
+            const res = await select({ message: q.prompt, options: opts });
+            if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+            answers[q.id] = res;
+          }
+        } else if (q.kind === "multiselect") {
+          const opts = (q.options ?? []).map((o) => ({ label: o, value: o }));
+          if (opts.length === 0) {
+            const res = await text({
+              message: q.prompt,
+              initialValue: Array.isArray(existing) ? existing.join(", ") : "",
+            });
+            if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+            const arr = String(res)
+              .split(",")
+              .map((s) => s.trim())
+              .filter(Boolean);
+            if (required && arr.length === 0)
+              return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+            answers[q.id] = arr;
+          } else {
+            const res = await multiselect({
+              message: q.prompt,
+              options: opts,
+              required: required ? true : false,
+            } as any);
+            if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+            const arr = Array.isArray(res) ? res : [];
+            if (required && arr.length === 0)
+              return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+            answers[q.id] = arr;
+          }
+        } else {
+          const res = await text({
+            message: q.prompt,
+            initialValue: existing ? String(existing) : "",
+          });
+          if (isCancel(res)) return { shouldContinue: false, reply: { text: "Cancelled." } };
+          const v = String(res).trim();
+          if (required && !v)
+            return { shouldContinue: false, reply: { text: `Missing required answer: ${q.id}` } };
+          answers[q.id] = v;
+        }
+
+        await writeJson(answersPath, answers);
+      }
+
+      await writeJson(questionsPath, { goal, questions });
+    }
+  }
+
   const md = buildPlanMarkdown(goal, answers, questions);
   await writeTextFile(planMdPath, md);
   await writeJson(metaPath, {