Reject empty collection coverage

AI assistance: Codex validated and addressed the Greptile empty-collection review finding with focused regression coverage.

skill/scripts/lib/staleness-deep.mjs

@@ -122,7 +122,10 @@ function hasCoverageValue(value) {
   if (value && typeof value === 'object') {
     return Object.values(value).some(hasCoverageValue);
   }
-  if (typeof value === 'string') return value.trim().length > 0;
+  if (typeof value === 'string') {
+    const trimmed = value.trim();
+    return trimmed.length > 0 && !/^(?:\[\s*\]|\{\s*\})$/.test(trimmed);
+  }
   return false;
 }
 

tests/doctor.test.mjs

@@ -239,6 +239,44 @@ describe('checkDesignCoverage', () => {
     }
   });
 
+  it('does not count empty frontmatter collection literals as section coverage', () => {
+    for (const colors of ['[]', '{}']) {
+      const design = [
+        '---',
+        'name: X',
+        `colors: ${colors}`,
+        'typography:',
+        '  body:',
+        '    fontFamily: Inter',
+        'components:',
+        '  button:',
+        '    backgroundColor: "#111111"',
+        '---',
+        '',
+        '# Design System: X',
+        '',
+      ].join('\n');
+      const findings = checkDesignCoverage({ design, designPath: 'DESIGN.md', parseDesignMd });
+      assert.deepEqual(ids(findings), ['design-md-coverage']);
+      assert.match(findings[0].summary, /no colors section/);
+    }
+  });
+
+  it('counts populated frontmatter array literals as section coverage', () => {
+    const design = [
+      '---',
+      'name: X',
+      'colors: ["#111111"]',
+      'typography: [Inter]',
+      'components: [button]',
+      '---',
+      '',
+      '# Design System: X',
+      '',
+    ].join('\n');
+    assert.deepEqual(checkDesignCoverage({ design, designPath: 'DESIGN.md', parseDesignMd }), []);
+  });
+
   it('reports nothing without a DESIGN.md', () => {
     assert.deepEqual(checkDesignCoverage({ design: null, parseDesignMd }), []);
   });