diff --git a/test/spec.spec.ts b/test/spec.spec.ts
new file mode 100644
index 0000000..61f59c1
--- /dev/null
+++ b/test/spec.spec.ts
@@ -0,0 +1,105 @@
+import { parseSpec } from '../src/utils/spec-parser.js';
+
+describe('Spec Parser', () => {
+  describe('JSON parsing', () => {
+    it('should parse valid JSON spec', () => {
+      const content = JSON.stringify({
+        name: 'test-cli',
+        version: '1.0.0',
+        description: 'A test CLI',
+        commands: [{ name: 'test', description: 'Test command' }],
+      });
+
+      const result = parseSpec({ content, format: 'json' });
+
+      expect(result.success).toBe(true);
+      expect(result.spec).toBeDefined();
+      expect(result.spec?.name).toBe('test-cli');
+      expect(result.spec?.version).toBe('1.0.0');
+    });
+
+    it('should detect JSON format automatically', () => {
+      const content = '{"name": "test", "version": "1.0.0", "description": "test", "commands": [{"name": "cmd", "description": "a command"}]}';
+      const result = parseSpec({ content, format: 'auto' });
+
+      expect(result.success).toBe(true);
+    });
+  });
+
+  describe('YAML parsing', () => {
+    it('should parse valid YAML spec', () => {
+      const content = `
+name: test-cli
+version: 1.0.0
+description: A test CLI
+commands:
+  - name: test
+    description: Test command
+`;
+
+      const result = parseSpec({ content, format: 'yaml' });
+
+      expect(result.success).toBe(true);
+      expect(result.spec).toBeDefined();
+      expect(result.spec?.name).toBe('test-cli');
+    });
+
+    it('should detect YAML format automatically', () => {
+      const content = 'name: test\nversion: 1.0.0\ndescription: test\ncommands:\n  - name: cmd\n    description: a command';
+      const result = parseSpec({ content, format: 'auto' });
+
+      expect(result.success).toBe(true);
+    });
+  });
+
+  describe('Error handling', () => {
+    it('should fail on invalid JSON', () => {
+      const content = '{invalid json}';
+      const result = parseSpec({ content, format: 'json' });
+
+      expect(result.success).toBe(false);
+      expect(result.errors).toBeDefined();
+      expect(result.errors?.length).toBeGreaterThan(0);
+    });
+
+    it('should fail on missing required fields', () => {
+      const content = JSON.stringify({
+        name: 'test',
+        commands: [],
+      });
+
+      const result = parseSpec({ content, format: 'json' });
+
+      expect(result.success).toBe(false);
+      expect(result.errors?.some((e) => e.includes('version'))).toBe(true);
+    });
+
+    it('should fail on empty commands array', () => {
+      const content = JSON.stringify({
+        name: 'test',
+        version: '1.0.0',
+        description: 'test',
+        commands: [],
+      });
+
+      const result = parseSpec({ content, format: 'json' });
+
+      expect(result.success).toBe(false);
+      expect(result.errors?.some((e) => e.includes('command'))).toBe(true);
+    });
+
+    it('should fail when file does not exist', () => {
+      const result = parseSpec({ filePath: '/nonexistent/path/spec.yaml' });
+
+      expect(result.success).toBe(false);
+      expect(result.errors?.some((e) => e.includes('not found'))).toBe(true);
+    });
+
+    it('should fail when no content or file path provided', () => {
+      const result = parseSpec({});
+
+      expect(result.success).toBe(false);
+      expect(result.errors?.some((e) => e.includes('filePath or content'))).toBe(true);
+    });
+  });
+});