diff --git a/node/rustchain_p2p_sync.py b/node/rustchain_p2p_sync.py
index 01d7cec50..5d6bc6c17 100644
--- a/node/rustchain_p2p_sync.py
+++ b/node/rustchain_p2p_sync.py
@@ -404,11 +404,15 @@ def stop_health_checks(self):
 
 def add_p2p_endpoints(app, peer_manager, block_sync, tx_gossip):
     """Add P2P endpoints to Flask app"""
+    from flask import jsonify, request
 
     @app.route('/p2p/announce', methods=['POST'])
     def announce_peer():
         """Endpoint for peer nodes to announce themselves"""
-        data = request.get_json()
+        data = request.get_json(silent=True)
+        if not isinstance(data, dict):
+            return jsonify({"ok": False, "error": "JSON object required"}), 400
+
         peer_url = data.get('peer_url')
 
         if peer_url:
diff --git a/node/tests/test_p2p_sync_routes.py b/node/tests/test_p2p_sync_routes.py
new file mode 100644
index 000000000..d676c38ad
--- /dev/null
+++ b/node/tests/test_p2p_sync_routes.py
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: MIT
+
+from flask import Flask
+
+from node.rustchain_p2p_sync import add_p2p_endpoints
+
+
+class StubPeerManager:
+    db_path = ":memory:"
+
+    def __init__(self):
+        self.peers = []
+
+    def add_peer(self, peer_url):
+        self.peers.append(peer_url)
+        return True
+
+    def get_active_peers(self):
+        return list(self.peers)
+
+
+def build_client():
+    app = Flask(__name__)
+    peer_manager = StubPeerManager()
+    add_p2p_endpoints(app, peer_manager, block_sync=None, tx_gossip=None)
+    return app.test_client(), peer_manager
+
+
+def test_p2p_announce_accepts_valid_peer_url():
+    client, peer_manager = build_client()
+
+    response = client.post("/p2p/announce", json={"peer_url": "http://peer.example:8088"})
+
+    assert response.status_code == 200
+    assert response.get_json() == {"ok": True, "peers": 1}
+    assert peer_manager.peers == ["http://peer.example:8088"]
+
+
+def test_p2p_announce_rejects_non_object_json():
+    client, _ = build_client()
+
+    response = client.post("/p2p/announce", json=["peer_url", "http://peer.example:8088"])
+
+    assert response.status_code == 400
+    assert response.get_json() == {"ok": False, "error": "JSON object required"}
+
+
+def test_p2p_announce_rejects_missing_peer_url():
+    client, _ = build_client()
+
+    response = client.post("/p2p/announce", json={})
+
+    assert response.status_code == 400
+    assert response.get_json() == {"ok": False, "error": "peer_url required"}