diff --git a/extensions/llm-task/src/llm-task-tool.test.ts b/extensions/llm-task/src/llm-task-tool.test.ts
index 6d21ec69654..0a41f0f4bad 100644
--- a/extensions/llm-task/src/llm-task-tool.test.ts
+++ b/extensions/llm-task/src/llm-task-tool.test.ts
@@ -1,4 +1,81 @@
 import { describe, it, expect, vi, beforeEach } from "vitest";
+
+vi.mock("@sinclair/typebox", () => ({
+  Type: {
+    Object: (schema: unknown) => schema,
+    String: (schema?: unknown) => schema,
+    Optional: (schema: unknown) => schema,
+    Unknown: (schema?: unknown) => schema,
+    Number: (schema?: unknown) => schema,
+  },
+}));
+
+vi.mock("ajv", () => ({
+  default: class MockAjv {
+    compile(schema: unknown) {
+      return (value: unknown) => {
+        if (
+          schema &&
+          typeof schema === "object" &&
+          !Array.isArray(schema) &&
+          (schema as { properties?: Record<string, { type?: string }> }).properties?.foo?.type ===
+            "string"
+        ) {
+          const ok = typeof (value as { foo?: unknown })?.foo === "string";
+          (this as { errors?: Array<{ instancePath: string; message: string }> }).errors = ok
+            ? undefined
+            : [{ instancePath: "/foo", message: "must be string" }];
+          return ok;
+        }
+        (this as { errors?: Array<{ instancePath: string; message: string }> }).errors = undefined;
+        return true;
+      };
+    }
+
+    errors?: Array<{ instancePath: string; message: string }>;
+  },
+}));
+
+vi.mock("../api.js", () => ({
+  formatXHighModelHint: () => "provider models that advertise xhigh reasoning",
+  normalizeThinkLevel: (raw?: string | null) => {
+    if (!raw) {
+      return undefined;
+    }
+    const key = raw.trim().toLowerCase();
+    const collapsed = key.replace(/[\s_-]+/g, "");
+    if (collapsed === "adaptive" || collapsed === "auto") {
+      return "adaptive";
+    }
+    if (collapsed === "xhigh" || collapsed === "extrahigh") {
+      return "xhigh";
+    }
+    if (["off"].includes(key)) {
+      return "off";
+    }
+    if (["on", "enable", "enabled"].includes(key)) {
+      return "low";
+    }
+    if (["min", "minimal", "think"].includes(key)) {
+      return "minimal";
+    }
+    if (["low", "thinkhard", "think-hard", "think_hard"].includes(key)) {
+      return "low";
+    }
+    if (["mid", "med", "medium", "thinkharder", "think-harder", "harder"].includes(key)) {
+      return "medium";
+    }
+    if (
+      ["high", "ultra", "ultrathink", "think-hard", "thinkhardest", "highest", "max"].includes(key)
+    ) {
+      return "high";
+    }
+    return undefined;
+  },
+  resolvePreferredOpenClawTmpDir: () => "/tmp",
+  supportsXHighThinking: () => false,
+}));
+
 import { createLlmTaskTool } from "./llm-task-tool.js";
 
 const runEmbeddedPiAgent = vi.fn(async () => ({
@@ -137,6 +214,7 @@ describe("llm-task tool (json-only)", () => {
     await expect(tool.execute("id", { prompt: "x", thinking: "banana" })).rejects.toThrow(
       /invalid thinking level/i,
     );
+    expect(runEmbeddedPiAgent).not.toHaveBeenCalled();
   });
 
   it("throws on unsupported xhigh thinking level", async () => {
diff --git a/extensions/llm-task/src/llm-task-tool.ts b/extensions/llm-task/src/llm-task-tool.ts
index 47c7efbea76..77d76fb2dfb 100644
--- a/extensions/llm-task/src/llm-task-tool.ts
+++ b/extensions/llm-task/src/llm-task-tool.ts
@@ -3,7 +3,6 @@ import path from "node:path";
 import { Type } from "@sinclair/typebox";
 import Ajv from "ajv";
 import {
-  formatThinkingLevels,
   formatXHighModelHint,
   normalizeThinkLevel,
   resolvePreferredOpenClawTmpDir,
@@ -45,6 +44,9 @@ type PluginCfg = {
   timeoutMs?: number;
 };
 
+const INVALID_THINKING_LEVELS_HINT =
+  "off, minimal, low, medium, high, adaptive, and xhigh where supported";
+
 export function createLlmTaskTool(api: OpenClawPluginApi) {
   return {
     name: "llm-task",
@@ -125,7 +127,7 @@ export function createLlmTaskTool(api: OpenClawPluginApi) {
       const thinkLevel = thinkingRaw ? normalizeThinkLevel(thinkingRaw) : undefined;
       if (thinkingRaw && !thinkLevel) {
         throw new Error(
-          `Invalid thinking level "${thinkingRaw}". Use one of: ${formatThinkingLevels(provider, model)}.`,
+          `Invalid thinking level "${thinkingRaw}". Use one of: ${INVALID_THINKING_LEVELS_HINT}.`,
         );
       }
       if (thinkLevel === "xhigh" && !supportsXHighThinking(provider, model)) {