feat: add Unicode storage option to SQLAlchemySession

src/agents/extensions/memory/sqlalchemy_session.py

@@ -136,6 +136,7 @@ def __init__(
         sessions_table: str = "agent_sessions",
         messages_table: str = "agent_messages",
         session_settings: SessionSettings | None = None,
+        ensure_ascii: bool = True,
     ):
         """Initializes a new SQLAlchemySession.
 
@@ -150,10 +151,13 @@ def __init__(
             sessions_table (str, optional): Override the default table name for sessions if needed.
             messages_table (str, optional): Override the default table name for messages if needed.
             session_settings (SessionSettings | None, optional): Session configuration settings
+            ensure_ascii (bool, optional): Whether to escape non-ASCII characters when serializing
+                session items to JSON. Defaults to True to preserve the historical storage format.
         """
         self.session_id = session_id
         self.session_settings = session_settings or SessionSettings()
         self._engine = engine
+        self._ensure_ascii = ensure_ascii
         self._configure_sqlite_engine(engine)
         self._init_lock = (
             self._get_table_init_lock(engine, sessions_table, messages_table)
@@ -245,7 +249,7 @@ def from_url(
 
     async def _serialize_item(self, item: TResponseInputItem) -> str:
         """Serialize an item to JSON string. Can be overridden by subclasses."""
-        return json.dumps(item, separators=(",", ":"))
+        return json.dumps(item, ensure_ascii=self._ensure_ascii, separators=(",", ":"))
 
     async def _deserialize_item(self, item: str) -> TResponseInputItem:
         """Deserialize a JSON string to an item. Can be overridden by subclasses."""

tests/extensions/memory/test_sqlalchemy_session.py

@@ -106,6 +106,51 @@ async def test_sqlalchemy_session_direct_ops(agent: Agent):
     assert len(retrieved_after_clear) == 0
 
 
+async def test_sqlalchemy_session_defaults_to_escaped_non_ascii_storage():
+    """Default storage keeps the historical escaped non-ASCII JSON representation."""
+    session = SQLAlchemySession.from_url("default_ascii_storage", url=DB_URL, create_tables=True)
+    item: TResponseInputItem = {"role": "user", "content": "café"}
+
+    await session.add_items([item])
+
+    async with session._session_factory() as sess:
+        rows = await sess.execute(
+            select(session._messages.c.message_data).where(
+                session._messages.c.session_id == session.session_id
+            )
+        )
+        stored = rows.scalar_one()
+
+    assert "\\u00e9" in stored
+    assert "café" not in stored
+    assert await session.get_items() == [item]
+
+
+async def test_sqlalchemy_session_can_store_non_ascii_without_escaping():
+    """ensure_ascii=False stores multilingual content readably while preserving round-trip data."""
+    session = SQLAlchemySession.from_url(
+        "non_ascii_storage",
+        url=DB_URL,
+        create_tables=True,
+        ensure_ascii=False,
+    )
+    item: TResponseInputItem = {"role": "user", "content": "café"}
+
+    await session.add_items([item])
+
+    async with session._session_factory() as sess:
+        rows = await sess.execute(
+            select(session._messages.c.message_data).where(
+                session._messages.c.session_id == session.session_id
+            )
+        )
+        stored = rows.scalar_one()
+
+    assert "café" in stored
+    assert "\\u00e9" not in stored
+    assert await session.get_items() == [item]
+
+
 async def test_runner_integration(agent: Agent):
     """Test that SQLAlchemySession works correctly with the agent Runner."""
     session_id = "runner_integration_test"