fix: Allow ChildToolRule to work without support for structured outputs (#2270)

Co-authored-by: Mindy Long <mindy@letta.com>

tests/integration_test_agent_tool_graph.py

@@ -234,3 +234,51 @@ def test_claude_initial_tool_rule_enforced(mock_e2b_api_key_none):
         if i < 2:
             backoff_time = 10 * (2 ** i)
             time.sleep(backoff_time)
+
+@pytest.mark.timeout(60)  # Sets a 60-second timeout for the test since this could loop infinitely
+def test_agent_no_structured_output_with_one_child_tool(mock_e2b_api_key_none):
+    client = create_client()
+    cleanup(client=client, agent_uuid=agent_uuid)
+
+    send_message = client.server.tool_manager.get_tool_by_name(tool_name="send_message", actor=client.user)
+    archival_memory_search = client.server.tool_manager.get_tool_by_name(tool_name="archival_memory_search", actor=client.user)
+    archival_memory_insert = client.server.tool_manager.get_tool_by_name(tool_name="archival_memory_insert", actor=client.user)
+
+    # Make tool rules
+    tool_rules = [
+        InitToolRule(tool_name="archival_memory_search"),
+        ChildToolRule(tool_name="archival_memory_search", children=["archival_memory_insert"]),
+        ChildToolRule(tool_name="archival_memory_insert", children=["send_message"]),
+        TerminalToolRule(tool_name="send_message"),
+    ]
+    tools = [send_message, archival_memory_search, archival_memory_insert]
+
+    config_files = [
+        "tests/configs/llm_model_configs/claude-3-sonnet-20240229.json",
+        "tests/configs/llm_model_configs/openai-gpt-4o.json",
+    ]
+
+    for config in config_files:
+        agent_state = setup_agent(client, config, agent_uuid=agent_uuid, tool_ids=[t.id for t in tools], tool_rules=tool_rules)
+        response = client.user_message(agent_id=agent_state.id, message="hi. run archival memory search")
+
+        # Make checks
+        assert_sanity_checks(response)
+
+        # Assert the tools were called
+        assert_invoked_function_call(response.messages, "archival_memory_search")
+        assert_invoked_function_call(response.messages, "archival_memory_insert")
+        assert_invoked_function_call(response.messages, "send_message")
+
+        # Check ordering of tool calls
+        tool_names = [t.name for t in [archival_memory_search, archival_memory_insert, send_message]]
+        for m in response.messages:
+            if isinstance(m, FunctionCallMessage):
+                # Check that it's equal to the first one
+                assert m.function_call.name == tool_names[0]
+
+                # Pop out first one
+                tool_names = tool_names[1:]
+
+        print(f"Got successful response from client: \n\n{response}")
+        cleanup(client=client, agent_uuid=agent_uuid)