diff --git a/tests/test_issue_624.py b/tests/test_issue_624.py
new file mode 100644
index 00000000..9e306b2b
--- /dev/null
+++ b/tests/test_issue_624.py
@@ -0,0 +1,31 @@
+"""Regression test for issue #624 — startup must not probe external IP services."""
+
+import requests
+
+from agentfield import Agent
+from agentfield import agent as agent_mod
+
+
+def test_issue_624(monkeypatch):
+    """An explicit Kubernetes callback URL must avoid metadata and ipify probes."""
+    requests_made = []
+
+    class DummyResponse:
+        status_code = 404
+        text = ""
+
+    def fake_get(url, *args, **kwargs):
+        requests_made.append(url)
+        return DummyResponse()
+
+    monkeypatch.setattr(agent_mod, "_is_running_in_container", lambda: True)
+    monkeypatch.setattr(requests, "get", fake_get)
+
+    Agent(
+        node_id="issue-624-agent",
+        callback_url="http://issue-624-agent.default.svc.cluster.local:8001",
+        auto_register=False,
+        enable_did=False,
+    )
+
+    assert requests_made == []