fix(core): strengthen language control in aiDescribe prompt (#2067)

The previous prompt had "Use ${language}." appended to the first sentence,
which was ambiguous and easily overridden by the all-English few-shot
examples. This change:

- Separates the language instruction into a standalone "IMPORTANT" directive
- Adds a redundant reminder in the GUIDELINES section
- Provides Chinese examples when preferredLanguage is Chinese, so the
  few-shot signal aligns with the language instruction

https://claude.ai/code/session_01A2hhpJ74in5M6cL2Qj2HrR

Co-authored-by: Claude <noreply@anthropic.com>

Author: ottomao

packages/core/src/ai-model/prompt/describe.ts

@@ -1,8 +1,34 @@
 import { getPreferredLanguage } from '@midscene/shared/env';
 
+const examplesMap: Record<string, string[]> = {
+  Chinese: [
+    '"登录表单中的"登录"按钮"',
+    '"搜索输入框，placeholder 为"请输入关键词""',
+    '"顶部导航栏中文字为"首页"的链接"',
+    '"联系表单中的提交按钮"',
+    '"aria-label 为"打开菜单"的菜单图标"',
+  ],
+  English: [
+    '"Login button with text \'Sign In\'"',
+    '"Search input with placeholder \'Enter keywords\'"',
+    '"Navigation link with text \'Home\' in header"',
+    '"Submit button in contact form"',
+    '"Menu icon with aria-label \'Open menu\'"',
+  ],
+};
+
+const getExamples = (language: string) => {
+  const examples = examplesMap[language] || examplesMap.English;
+  return examples.map((e) => `- ${e}`).join('\n');
+};
+
 export const elementDescriberInstruction = () => {
+  const preferredLanguage = getPreferredLanguage();
+
   return `
-Describe the element in the red rectangle for precise identification. Use ${getPreferredLanguage()}.
+Describe the element in the red rectangle for precise identification.
+
+IMPORTANT: You MUST write the description in ${preferredLanguage}.
 
 CRITICAL REQUIREMENTS:
 1. UNIQUENESS: The description must uniquely identify this element on the current page
@@ -28,13 +54,10 @@ GUIDELINES:
 - Avoid page-specific or temporary content
 - Don't mention the red rectangle or selection box
 - Focus on stable, reusable characteristics
+- **Write the description in ${preferredLanguage}**
 
 EXAMPLES:
-- "Login button with text 'Sign In'"
-- "Search input with placeholder 'Enter keywords'"
-- "Navigation link with text 'Home' in header"
-- "Submit button in contact form"
-- "Menu icon with aria-label 'Open menu'"
+${getExamples(preferredLanguage)}
 
 Return JSON:
 {

packages/core/tests/unit-test/prompt/__snapshots__/describe.test.ts.snap

@@ -2,7 +2,9 @@
 
 exports[`elementDescriberInstruction > should return the correct instruction 1`] = `
 "
-Describe the element in the red rectangle for precise identification. Use English.
+Describe the element in the red rectangle for precise identification.
+
+IMPORTANT: You MUST write the description in English.
 
 CRITICAL REQUIREMENTS:
 1. UNIQUENESS: The description must uniquely identify this element on the current page
@@ -28,6 +30,7 @@ GUIDELINES:
 - Avoid page-specific or temporary content
 - Don't mention the red rectangle or selection box
 - Focus on stable, reusable characteristics
+- **Write the description in English**
 
 EXAMPLES:
 - "Login button with text 'Sign In'"