diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 775437f92..c68665521 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -4,6 +4,9 @@
 
 ### Fixed
 
+- Fixed `normalizePlanTitle` rejecting plan titles that contain spaces or common punctuation (e.g. "My Feature Plan") — spaces are now converted to hyphens and other invalid characters are dropped, so models that produce natural-language plan titles no longer loop forever trying to call `resolve`. ([#1176](https://github.com/can1357/oh-my-pi/issues/1176))
+- Fixed `ask` tool prompt example showing the legacy `question`/`options` top-level format instead of the current `questions: [{id, question, options}]` array format; models that closely followed the example generated calls that always failed schema validation. ([#1176](https://github.com/can1357/oh-my-pi/issues/1176))
+
 - Fixed ACP command and custom tool-call notifications to carry the original tool arguments in replayed and final updates, so command text is preserved and raw input is no longer wrapped
 - Fixed ACP async-job draining to be scoped by session owner so `getAsyncJobSnapshot` and `drainAsyncJobDeliveriesForAcp` no longer consume or expose jobs from other sessions
 - Fixed async job status reporting to include in-flight completions so queued/delivering indicators remain accurate while callbacks are still running
diff --git a/packages/coding-agent/src/plan-mode/approved-plan.ts b/packages/coding-agent/src/plan-mode/approved-plan.ts
index 1e0d3388d..4733b837a 100644
--- a/packages/coding-agent/src/plan-mode/approved-plan.ts
+++ b/packages/coding-agent/src/plan-mode/approved-plan.ts
@@ -14,10 +14,12 @@ export interface PlanApprovalDetails {
 	planExists: boolean;
 }
 
-/** Validate the agent-supplied plan title and derive the destination filename.
- *  Filename uses the title with a `.md` suffix; characters are restricted to
- *  letters, numbers, underscores, and hyphens so the value is safe to splice
- *  into a `local://` URL without escaping. */
+/** Validate and normalize the agent-supplied plan title into a safe filename stem.
+ *  Spaces and other URL-safe punctuation are replaced with hyphens so models that
+ *  produce natural-language titles (e.g. "My feature plan") still succeed.
+ *  Characters that cannot be safely represented after replacement are dropped.
+ *  The result is restricted to letters, numbers, underscores, and hyphens so it
+ *  is safe to splice into a `local://` URL without escaping. */
 export function normalizePlanTitle(title: string): { title: string; fileName: string } {
 	const trimmed = title.trim();
 	if (!trimmed) {
@@ -28,13 +30,23 @@ export function normalizePlanTitle(title: string): { title: string; fileName: st
 		throw new ToolError("Plan title must not contain path separators or '..'.");
 	}
 
-	const withExtension = trimmed.toLowerCase().endsWith(".md") ? trimmed : `${trimmed}.md`;
-	if (!/^[A-Za-z0-9_-]+\.md$/.test(withExtension)) {
-		throw new ToolError("Plan title may only contain letters, numbers, underscores, or hyphens.");
+	// Strip a trailing `.md` if the model included it, then sanitize:
+	// spaces → hyphens, any remaining invalid char → dropped.
+	const withoutExt = trimmed.replace(/\.md$/i, "");
+	const sanitized = withoutExt
+		.replace(/\s+/g, "-")
+		.replace(/[^A-Za-z0-9_-]/g, "")
+		.replace(/-{2,}/g, "-")
+		.replace(/^-+|-+$/g, "");
+
+	if (!sanitized) {
+		throw new ToolError(
+			"Plan title must contain at least one letter, number, underscore, or hyphen after sanitization.",
+		);
 	}
 
-	const normalizedTitle = withExtension.slice(0, -3);
-	return { title: normalizedTitle, fileName: withExtension };
+	const fileName = `${sanitized}.md`;
+	return { title: sanitized, fileName };
 }
 
 /** Humanize a normalized plan title for use as a session display name.
diff --git a/packages/coding-agent/src/prompts/tools/ask.md b/packages/coding-agent/src/prompts/tools/ask.md
index 9620922bb..631ac3356 100644
--- a/packages/coding-agent/src/prompts/tools/ask.md
+++ b/packages/coding-agent/src/prompts/tools/ask.md
@@ -22,7 +22,8 @@ Asks user when you need clarification or input during task execution.
 
 <examples>
 # Single question
-question: "Which authentication method should this API use?"
-options: [{"label": "JWT"}, {"label": "OAuth2"}, {"label": "Session cookies"}]
-recommended: 0
+questions: [{"id": "auth_method", "question": "Which authentication method should this API use?", "options": [{"label": "JWT"}, {"label": "OAuth2"}, {"label": "Session cookies"}], "recommended": 0}]
+
+# Multiple questions
+questions: [{"id": "storage_type", "question": "Which storage backend?", "options": [{"label": "SQLite"}, {"label": "PostgreSQL"}]}, {"id": "auth_method", "question": "Which auth method?", "options": [{"label": "JWT"}, {"label": "Session cookies"}]}]
 </examples>
diff --git a/packages/coding-agent/test/plan-mode/approved-plan.test.ts b/packages/coding-agent/test/plan-mode/approved-plan.test.ts
index 327c02e22..6d3c66185 100644
--- a/packages/coding-agent/test/plan-mode/approved-plan.test.ts
+++ b/packages/coding-agent/test/plan-mode/approved-plan.test.ts
@@ -2,7 +2,7 @@ import { afterEach, beforeEach, describe, expect, it } from "bun:test";
 import * as fs from "node:fs/promises";
 import * as os from "node:os";
 import * as path from "node:path";
-import { humanizePlanTitle, renameApprovedPlanFile } from "@oh-my-pi/pi-coding-agent/plan-mode/approved-plan";
+import { humanizePlanTitle, normalizePlanTitle, renameApprovedPlanFile } from "@oh-my-pi/pi-coding-agent/plan-mode/approved-plan";
 
 describe("renameApprovedPlanFile", () => {
 	let tmpDir: string;
@@ -62,3 +62,47 @@ describe("humanizePlanTitle", () => {
 		expect(humanizePlanTitle("---")).toBe("");
 	});
 });
+
+describe("normalizePlanTitle", () => {
+	it("accepts a clean identifier as-is", () => {
+		expect(normalizePlanTitle("my-plan")).toEqual({ title: "my-plan", fileName: "my-plan.md" });
+		expect(normalizePlanTitle("feature_branch")).toEqual({ title: "feature_branch", fileName: "feature_branch.md" });
+	});
+
+	it("strips a trailing .md suffix provided by the model", () => {
+		expect(normalizePlanTitle("my-plan.md")).toEqual({ title: "my-plan", fileName: "my-plan.md" });
+	});
+
+	it("converts spaces to hyphens (natural-language titles)", () => {
+		expect(normalizePlanTitle("My Improvement Plan")).toEqual({
+			title: "My-Improvement-Plan",
+			fileName: "My-Improvement-Plan.md",
+		});
+	});
+
+	it("collapses consecutive spaces / resulting hyphens", () => {
+		expect(normalizePlanTitle("foo  bar")).toEqual({ title: "foo-bar", fileName: "foo-bar.md" });
+	});
+
+	it("drops characters outside the allowed set after space replacement", () => {
+		expect(normalizePlanTitle("plan: v1.0 (draft)")).toEqual({ title: "plan-v10-draft", fileName: "plan-v10-draft.md" });
+	});
+
+	it("trims leading/trailing hyphens that result from sanitization", () => {
+		expect(normalizePlanTitle("!!! plan !!!")).toEqual({ title: "plan", fileName: "plan.md" });
+	});
+
+	it("throws for empty title", () => {
+		expect(() => normalizePlanTitle("")).toThrow("Plan title is required");
+		expect(() => normalizePlanTitle("   ")).toThrow("Plan title is required");
+	});
+
+	it("throws for path separators", () => {
+		expect(() => normalizePlanTitle("../etc/passwd")).toThrow("path separators");
+		expect(() => normalizePlanTitle("a/b")).toThrow("path separators");
+	});
+
+	it("throws when sanitization produces empty result", () => {
+		expect(() => normalizePlanTitle("!!!")).toThrow("at least one letter");
+	});
+});
diff --git a/packages/tui/CHANGELOG.md b/packages/tui/CHANGELOG.md
index 0a133389b..b536d5622 100644
--- a/packages/tui/CHANGELOG.md
+++ b/packages/tui/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed `renderInlineMarkdown` crashing with `TypeError: undefined is not an object (evaluating 'e.replace')` when called with a non-string value during streaming — partial JSON parsing leaves option label fields temporarily unpopulated, causing the ask tool renderer to fail. ([#1176](https://github.com/can1357/oh-my-pi/issues/1176))
+
 ## [15.0.2] - 2026-05-15
 
 ### Added
diff --git a/packages/tui/src/components/markdown.ts b/packages/tui/src/components/markdown.ts
index d6b651946..65360b4de 100644
--- a/packages/tui/src/components/markdown.ts
+++ b/packages/tui/src/components/markdown.ts
@@ -946,6 +946,8 @@ export class Markdown implements Component {
  * Unlike the full Markdown component, this produces a single line with no block-level elements.
  */
 export function renderInlineMarkdown(text: string, mdTheme: MarkdownTheme, baseColor?: (t: string) => string): string {
+	// Guard against undefined/null during streaming — partial JSON can leave fields unpopulated.
+	if (typeof text !== "string") return (baseColor ?? (t => t))(text != null ? String(text) : "");
 	const tokens = marked.lexer(text);
 	const applyText = baseColor ?? ((t: string) => t);
 	let result = "";
diff --git a/packages/tui/test/markdown.test.ts b/packages/tui/test/markdown.test.ts
index 2eba2bc9e..f6f84f1bd 100644
--- a/packages/tui/test/markdown.test.ts
+++ b/packages/tui/test/markdown.test.ts
@@ -27,6 +27,22 @@ describe("renderInlineMarkdown", () => {
 
 		expect(plain).toBe("1. Review against a base branch (PR Style)");
 	});
+
+	it("returns empty string for undefined input (streaming guard)", () => {
+		// During streaming, partial JSON can leave option label fields as undefined.
+		// renderInlineMarkdown must not throw in that case.
+		const rendered = renderInlineMarkdown(undefined as unknown as string, defaultMarkdownTheme);
+		expect(rendered).toBe("");
+	});
+
+	it("applies baseColor to fallback for non-string input", () => {
+		const rendered = renderInlineMarkdown(
+			null as unknown as string,
+			defaultMarkdownTheme,
+			t => `[${t}]`,
+		);
+		expect(rendered).toBe("[]");
+	});
 });
 
 describe("Markdown component", () => {