diff --git a/gitnexus/test/unit/git-clone.test.ts b/gitnexus/test/unit/git-clone.test.ts
index 637ff5932..2df5a0a5e 100644
--- a/gitnexus/test/unit/git-clone.test.ts
+++ b/gitnexus/test/unit/git-clone.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { extractRepoName, getCloneDir } from '../../src/server/git-clone.js';
+import { extractRepoName, getCloneDir, validateGitUrl } from '../../src/server/git-clone.js';
 
 describe('git-clone', () => {
   describe('extractRepoName', () => {
@@ -32,4 +32,86 @@ describe('git-clone', () => {
       expect(dir).toContain('my-repo');
     });
   });
+
+  describe('validateGitUrl', () => {
+    it('allows valid HTTPS GitHub URLs', () => {
+      expect(() => validateGitUrl('https://github.com/user/repo.git')).not.toThrow();
+      expect(() => validateGitUrl('https://github.com/user/repo')).not.toThrow();
+    });
+
+    it('allows valid HTTP URLs', () => {
+      expect(() => validateGitUrl('http://gitlab.com/user/repo.git')).not.toThrow();
+    });
+
+    it('blocks SSH protocol', () => {
+      expect(() => validateGitUrl('ssh://git@github.com/user/repo.git')).toThrow(
+        'Only https:// and http://',
+      );
+    });
+
+    it('blocks file:// protocol', () => {
+      expect(() => validateGitUrl('file:///etc/passwd')).toThrow(
+        'Only https:// and http://',
+      );
+    });
+
+    it('blocks IPv4 loopback', () => {
+      expect(() => validateGitUrl('http://127.0.0.1/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://127.255.0.1/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks IPv6 loopback ::1', () => {
+      // Node URL parser strips brackets: hostname is "::1" not "[::1]"
+      expect(() => validateGitUrl('http://[::1]/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks IPv4 private ranges (10.x, 172.16-31.x, 192.168.x)', () => {
+      expect(() => validateGitUrl('http://10.0.0.1/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://172.16.0.1/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://172.31.255.255/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://192.168.1.1/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks link-local addresses', () => {
+      expect(() => validateGitUrl('http://169.254.1.1/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks cloud metadata hostname', () => {
+      expect(() => validateGitUrl('http://metadata.google.internal/repo')).toThrow(
+        'private/internal',
+      );
+      expect(() => validateGitUrl('http://metadata.azure.com/repo')).toThrow(
+        'private/internal',
+      );
+    });
+
+    it('blocks IPv6 ULA (fc/fd)', () => {
+      expect(() => validateGitUrl('http://[fc00::1]/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://[fd12::1]/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks IPv6 link-local (fe80)', () => {
+      expect(() => validateGitUrl('http://[fe80::1]/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks IPv4-mapped IPv6', () => {
+      expect(() => validateGitUrl('http://[::ffff:127.0.0.1]/repo.git')).toThrow(
+        'private/internal',
+      );
+    });
+
+    it('does not block valid public IPs', () => {
+      expect(() => validateGitUrl('https://140.82.121.4/repo.git')).not.toThrow();
+    });
+
+    it('blocks CGN range (100.64.0.0/10)', () => {
+      expect(() => validateGitUrl('http://100.64.0.1/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://100.127.255.255/repo.git')).toThrow('private/internal');
+    });
+
+    it('blocks benchmarking range (198.18.0.0/15)', () => {
+      expect(() => validateGitUrl('http://198.18.0.1/repo.git')).toThrow('private/internal');
+      expect(() => validateGitUrl('http://198.19.255.255/repo.git')).toThrow('private/internal');
+    });
+  });
 });