fix(core): refine simple frontmatter parser key detection

- Restrict multi-line description continuation check to known keys (name, description)
- Avoid incorrectly identifying lines starting with "Note:" or similar as new keys
- Add test case to verify the fix

Fixes https://github.com/google-gemini/gemini-cli/issues/25693

packages/core/src/skills/skillLoader.test.ts

@@ -343,4 +343,28 @@ description: A long description: with a colon
     expect(skills[0].name).toBe('my-skill');
     expect(skills[0].description).toBe('A long description: with a colon');
   });
+
+  it('should not treat "Note:" as a new key in multi-line description in simple parser', async () => {
+    const skillDir = path.join(testRootDir, 'simple-parser-note');
+    await fs.mkdir(skillDir, { recursive: true });
+    const skillFile = path.join(skillDir, 'SKILL.md');
+    // Forces YAML failure, triggers simple parser
+    await fs.writeFile(
+      skillFile,
+      `---
+name: note-skill
+description: This is a description
+  Note: This should be part of the description
+---
+`,
+    );
+
+    const skills = await loadSkillsFromDir(testRootDir);
+
+    expect(skills).toHaveLength(1);
+    expect(skills[0].name).toBe('note-skill');
+    expect(skills[0].description).toBe(
+      'This is a description Note: This should be part of the description',
+    );
+  });
 });

packages/core/src/skills/skillLoader.ts

@@ -92,8 +92,11 @@ function parseSimpleFrontmatter(
       while (i + 1 < lines.length) {
         const nextLine = lines[i + 1];
         // If next line is indented, it's a continuation of the description,
-        // UNLESS it looks like another key (e.g. "name:")
-        if (nextLine.match(/^[ \t]+\S/) && !nextLine.match(/^\s*\w+\s*:/)) {
+        // UNLESS it looks like another known key (e.g. "name:")
+        if (
+          nextLine.match(/^[ \t]+\S/) &&
+          !nextLine.match(/^\s*(name|description)\s*:/i)
+        ) {
           descLines.push(nextLine.trim());
           i++;
         } else {