diff --git a/README.md b/README.md
index 50eb00f..fa8bd27 100644
--- a/README.md
+++ b/README.md
@@ -693,7 +693,7 @@ Notice that nearly every feature below has at least subtle differences from Java
       ✔ Includes all JS forms<br>
       ✔ Adds <code>{,n}</code> for min 0<br>
       ✔ Explicit bounds have upper limit of 100,000 (unlimited in JS)<br>
-      ✔ Error with assertions (same as JS with flag <code>u</code>, <code>v</code>)<br>
+      ✔ Error with assertions (same as JS with flag <code>u</code>, <code>v</code>) and directives<br>
     </td>
   </tr>
   <tr valign="top">
diff --git a/spec/match-directive.spec.js b/spec/match-directive.spec.js
index d66bc8b..f306276 100644
--- a/spec/match-directive.spec.js
+++ b/spec/match-directive.spec.js
@@ -1,3 +1,4 @@
+import {toDetails} from '../dist/index.mjs';
 import {r} from '../src/utils.js';
 import {matchers} from './helpers/matchers.js';
 
@@ -5,17 +6,24 @@ beforeEach(() => {
   jasmine.addMatchers(matchers);
 });
 
-// TODO: Add me
-// describe('Directive', () => {
-//   describe('flags', () => {
-//     it('should', () => {
-//       expect('').toExactlyMatch(r``);
-//     });
-//   });
+describe('Directive', () => {
+  describe('flags', () => {
+    it('should not allow quantification', () => {
+      expect(() => toDetails('(?i)+')).toThrow();
+      expect(() => toDetails('(?imx)+')).toThrow();
+      expect(() => toDetails('(?-i)+')).toThrow();
+      expect(() => toDetails('(?im-x)+')).toThrow();
+    });
 
-//   describe('keep', () => {
-//     it('should', () => {
-//       expect('').toExactlyMatch(r``);
-//     });
-//   });
-// });
+    // TODO: Add remaining
+  });
+
+  describe('keep', () => {
+    it('should not allow quantification', () => {
+      expect(() => toDetails(r`\K+`)).toThrow();
+      expect(() => toDetails(r`a\K+a`)).toThrow();
+    });
+
+    // TODO: Add remaining
+  });
+});