diff --git a/sdk/python/agentfield/memory_events.py b/sdk/python/agentfield/memory_events.py
index 53a754b3f..e58bcae1b 100644
--- a/sdk/python/agentfield/memory_events.py
+++ b/sdk/python/agentfield/memory_events.py
@@ -4,6 +4,7 @@
 from datetime import datetime
 from functools import wraps
 from typing import Any, Callable, Dict, List, Optional, Union
+from urllib.parse import urlencode
 
 import websockets
 
@@ -152,16 +153,16 @@ async def connect(
                 ws_url = f"{self.base_url}/api/v1/memory/events/ws"
 
                 # Add query parameters for server-side filtering
-                query_params = []
+                query_params = {}
                 if patterns:
-                    query_params.append(f"patterns={','.join(patterns)}")
+                    query_params["patterns"] = ",".join(patterns)
                 if scope:
-                    query_params.append(f"scope={scope}")
+                    query_params["scope"] = scope
                 if scope_id:
-                    query_params.append(f"scope_id={scope_id}")
+                    query_params["scope_id"] = scope_id
 
                 if query_params:
-                    ws_url += "?" + "&".join(query_params)
+                    ws_url += "?" + urlencode(query_params)
 
                 self.websocket = await asyncio.wait_for(
                     websockets.connect(ws_url, **{_HEADERS_KWARG: headers}),
diff --git a/sdk/python/tests/test_memory_events.py b/sdk/python/tests/test_memory_events.py
index f91080b59..ceecd4e57 100644
--- a/sdk/python/tests/test_memory_events.py
+++ b/sdk/python/tests/test_memory_events.py
@@ -1,6 +1,7 @@
 import asyncio
 import json
 from types import SimpleNamespace
+from urllib.parse import parse_qs, urlsplit
 
 import websockets
 
@@ -161,7 +162,18 @@ async def get(self, url, params=None, headers=None, timeout=None):
 
 
 @pytest.mark.asyncio
-async def test_memory_event_client_connect_builds_ws_url(monkeypatch):
+@pytest.mark.parametrize(
+    ("patterns", "scope", "scope_id"),
+    [
+        (["cart.*", "order.*"], "session", "abc"),
+        (["user+plan.*"], "actor", "alice+trial@example.com"),
+        (["cart&total.*", "issue#*"], "session", "team&env=prod#1"),
+        (["user preferences.*", "用户.*"], "workflow", "会话 + 1"),
+    ],
+)
+async def test_memory_event_client_connect_builds_ws_url(
+    monkeypatch, patterns, scope, scope_id
+):
     ctx = SimpleNamespace(to_headers=lambda: {"Authorization": "token"})
     client = MemoryEventClient("http://agentfield", ctx)
 
@@ -174,7 +186,9 @@ def __init__(self):
 
     async def fake_connect(url, **kwargs):
         record["url"] = url
-        record["headers"] = kwargs.get("additional_headers") or kwargs.get("extra_headers")
+        record["headers"] = kwargs.get("additional_headers") or kwargs.get(
+            "extra_headers"
+        )
         return DummyWebSocket()
 
     async def fake_listen(self):
@@ -183,15 +197,19 @@ async def fake_listen(self):
     monkeypatch.setattr("agentfield.memory_events.websockets.connect", fake_connect)
     monkeypatch.setattr(MemoryEventClient, "_listen", fake_listen, raising=False)
 
-    await client.connect(
-        patterns=["cart.*", "order.*"], scope="session", scope_id="abc"
-    )
+    await client.connect(patterns=patterns, scope=scope, scope_id=scope_id)
     await asyncio.sleep(0)
 
-    assert record["url"].startswith("ws://agentfield")
-    assert "patterns=cart.*,order.*" in record["url"]
-    assert "scope=session" in record["url"]
-    assert "scope_id=abc" in record["url"]
+    parsed_url = urlsplit(record["url"])
+    assert parsed_url.scheme == "ws"
+    assert parsed_url.netloc == "agentfield"
+    assert parsed_url.path == "/api/v1/memory/events/ws"
+    assert parsed_url.fragment == ""
+    assert parse_qs(parsed_url.query) == {
+        "patterns": [",".join(patterns)],
+        "scope": [scope],
+        "scope_id": [scope_id],
+    }
     assert record["headers"] == {"Authorization": "token"}
     assert listener_called.get("run") is True
 
@@ -225,6 +243,7 @@ def __init__(self):
 
     async def fake_connect(url, **kwargs):
         called_with.update(kwargs)
+        called_with["url"] = url
         return DummyWebSocket()
 
     monkeypatch.setattr("agentfield.memory_events.websockets.connect", fake_connect)
@@ -235,6 +254,7 @@ async def fake_connect(url, **kwargs):
 
     assert _HEADERS_KWARG in called_with
     assert called_with[_HEADERS_KWARG] == {"Authorization": "token"}
+    assert called_with["url"] == "ws://agentfield/api/v1/memory/events/ws"
 
 
 @pytest.mark.asyncio
@@ -260,7 +280,9 @@ async def fake_reconnect(self):
     # Give the background task a chance to start
     await asyncio.sleep(0.05)
 
-    assert reconnect_started.is_set(), "reconnect should have been started in background"
+    assert reconnect_started.is_set(), (
+        "reconnect should have been started in background"
+    )
     assert not client.is_listening