diff --git a/src/rule/url.ts b/src/rule/url.ts
index 34a5b1d..5acc0a4 100644
--- a/src/rule/url.ts
+++ b/src/rule/url.ts
@@ -53,7 +53,7 @@ export default () => {
   const tld = `(?:\\.(?:[a-z\\u00a1-\\uffff]{2,}))`;
   const port = '(?::\\d{2,5})?';
   const path = '(?:[/?#][^\\s"]*)?';
-  const regex = `(?:${protocol}|www\\.)${auth}(?:localhost|${ipv4}|${ipv6}|${host}${domain}${tld})${port}${path}`;
+  const regex = `(?:${protocol}|www\\.)${auth}(?:localhost|${ipv4}|${ipv6}|${host}(?:${domain}${tld})?)${port}${path}`;
   urlReg = new RegExp(`(?:^${regex}$)`, 'i');
   return urlReg;
 };
diff --git a/tests/url.spec.ts b/tests/url.spec.ts
index 763d38c..49d7426 100644
--- a/tests/url.spec.ts
+++ b/tests/url.spec.ts
@@ -33,6 +33,39 @@ describe('url', () => {
     );
   });
 
+  it('works for single-label host url', done => {
+    new Schema({
+      v: {
+        type: 'url',
+      },
+    }).validate(
+      {
+        v: 'http://fastapi:3000/mcp',
+      },
+      errors => {
+        expect(errors).toBe(null);
+        done();
+      },
+    );
+  });
+
+  it('rejects invalid single-label host url', done => {
+    new Schema({
+      v: {
+        type: 'url',
+      },
+    }).validate(
+      {
+        v: 'http://-fastapi:3000/mcp',
+      },
+      errors => {
+        expect(errors).toHaveLength(1);
+        expect(errors[0].message).toBe('v is not a valid url');
+        done();
+      },
+    );
+  });
+
   it('works for required empty string', done => {
     new Schema({
       v: {