diff --git a/plugins/memory/hindsight/__init__.py b/plugins/memory/hindsight/__init__.py
index b3126a0b2f..c40a65b3f3 100644
--- a/plugins/memory/hindsight/__init__.py
+++ b/plugins/memory/hindsight/__init__.py
@@ -890,7 +890,7 @@ class HindsightMemoryProvider(MemoryProvider):
         if session_id:
             self._session_id = str(session_id).strip()
 
-        turn = json.dumps(self._build_turn_messages(user_content, assistant_content))
+        turn = json.dumps(self._build_turn_messages(user_content, assistant_content), ensure_ascii=False)
         self._session_turns.append(turn)
         self._turn_counter += 1
         self._turn_index = self._turn_counter
diff --git a/tests/plugins/memory/test_hindsight_provider.py b/tests/plugins/memory/test_hindsight_provider.py
index db86f7626f..d916b25059 100644
--- a/tests/plugins/memory/test_hindsight_provider.py
+++ b/tests/plugins/memory/test_hindsight_provider.py
@@ -531,6 +531,22 @@ class TestSyncTurn:
         if provider._sync_thread:
             provider._sync_thread.join(timeout=5.0)
 
+    def test_sync_turn_preserves_unicode(self, provider_with_config):
+        """Non-ASCII text (CJK, ZWJ emoji) must survive JSON round-trip intact."""
+        p = provider_with_config()
+        p._client = _make_mock_client()
+        p.sync_turn("안녕 こんにちは 你好", "👨‍👩‍👧‍👦 family")
+        p._sync_thread.join(timeout=5.0)
+        p._client.aretain_batch.assert_called_once()
+        item = p._client.aretain_batch.call_args.kwargs["items"][0]
+        # ensure_ascii=False means non-ASCII chars appear as-is in the raw JSON,
+        # not as \uXXXX escape sequences.
+        raw_json = item["content"]
+        assert "안녕" in raw_json
+        assert "こんにちは" in raw_json
+        assert "你好" in raw_json
+        assert "👨‍👩‍👧‍👦" in raw_json
+
 
 # ---------------------------------------------------------------------------
 # System prompt tests