From 5de363cd9478383103af596886dcfc9f5bcf6701 Mon Sep 17 00:00:00 2001
From: Cursor Agent <cursoragent@cursor.com>
Date: Fri, 18 Sep 2026 06:27:20 +0000
Subject: [PATCH] chore(internals): cover skill validation error paths

Adds unit tests for directory name, title, empty files, non-string
content, and frontmatter mismatch in skills/utils.ts, raising line
coverage from 94.18% to 100% and branch coverage from 81.39% to 100%.
No behavior change.

Signed-off-by: Cursor Agent <cursoragent@cursor.com>
---
 .../internals/tools/src/skills/utils.test.ts  | 46 ++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

diff --git a/projects/internals/tools/src/skills/utils.test.ts b/projects/internals/tools/src/skills/utils.test.ts
index 242210c2cb..08e362c855 100644
--- a/projects/internals/tools/src/skills/utils.test.ts
+++ b/projects/internals/tools/src/skills/utils.test.ts
@@ -73,12 +73,26 @@ describe('validateSkillDescription', () => {
 });
 
 describe('validateSkillEntries', () => {
+  it('should validate the default registry', () => {
+    expect(() => validateSkillEntries()).not.toThrow();
+  });
+
   it('should reject duplicate skill names', () => {
     expect(() => validateSkillEntries([createSkill('duplicate'), createSkill('duplicate')])).toThrow(
       'Duplicate Agent Skill name "duplicate".'
     );
   });
 
+  it('should reject an empty title', () => {
+    expect(() => validateSkillEntries([createSkill('untitled', { title: ' ' })])).toThrow(
+      'Invalid Agent Skill title for "untitled".'
+    );
+  });
+
+  it('should require files', () => {
+    expect(() => validateSkillEntries([createSkill('empty', { files: {} })])).toThrow('must include files');
+  });
+
   it.each(['../outside.md', '/absolute.md', 'references\\windows.md', './SKILL.md'])(
     'should reject unsafe file path %s',
     filePath => {
@@ -89,14 +103,33 @@ describe('validateSkillEntries', () => {
     }
   );
 
+  it('should reject non-string file content', () => {
+    const skill = createSkill('binary');
+    const files = Object.assign(Object.create(null), skill.files, { 'notes.md': 1 }) as Skill['files'];
+    expect(() => validateSkillEntries([{ ...skill, files }])).toThrow(
+      'Invalid content for "notes.md" in Agent Skill "binary".'
+    );
+  });
+
   it('should require SKILL.md', () => {
     expect(() => validateSkillEntries([createSkill('missing', { files: { 'references/a.md': 'x' } })])).toThrow(
       'must include SKILL.md'
     );
   });
+
+  it('should require frontmatter to match the registry entry', () => {
+    expect(() => validateSkillEntries([createSkill('mismatch', { title: 'other title' })])).toThrow(
+      'Agent Skill "mismatch" frontmatter title does not match its registry entry.'
+    );
+  });
 });
 
 describe('createAgentSkillArtifacts', () => {
+  it('should create artifacts from the default registry', () => {
+    const artifacts = createAgentSkillArtifacts();
+    expect(artifacts.index.skills.map(skill => skill.name)).toEqual(skills.map(skill => skill.name).sort());
+  });
+
   it('should create deterministic single-file discovery entries', () => {
     const registry = [createSkill('zeta'), createSkill('alpha')];
     const artifacts = createAgentSkillArtifacts(registry);
@@ -141,6 +174,17 @@ describe('createAgentSkillArtifacts', () => {
 });
 
 describe('writeSkillDirectory', () => {
+  it('should require the directory name to match the skill name', async () => {
+    const root = await createTemporaryDirectory();
+    const skillDirectory = nodePath.join(root, 'wrong');
+    await expect(writeSkillDirectory(skillDirectory, createSkill('elements'))).rejects.toThrow(
+      'Agent Skill directory must end with "elements".'
+    );
+    expect(() => writeSkillDirectorySync(skillDirectory, createSkill('elements'))).toThrow(
+      'Agent Skill directory must end with "elements".'
+    );
+  });
+
   it('should update every bundled file and preserve user files', async () => {
     const root = await createTemporaryDirectory();
     const skill = createSkill('elements', {
@@ -184,7 +228,7 @@ describe('writeSkillDirectory', () => {
 describe('writeAgentSkillArtifacts', () => {
   it('should write the index and archive', async () => {
     const publicOutputPath = await createTemporaryDirectory();
-    await writeAgentSkillArtifacts(publicOutputPath, skills);
+    await writeAgentSkillArtifacts(publicOutputPath);
     const outputPath = nodePath.join(publicOutputPath, '.well-known', 'agent-skills');
     const index = JSON.parse(await fsp.readFile(nodePath.join(outputPath, 'index.json'), 'utf8'));