Missing first tool_calls message and Successfully transferred to hotel_agent tool message in supervisor's history

[usepr]

langgraph: Version: 0.4.9
langgraph-supervisor: Version: 0.0.27
llm model used: qwen3-0.6B

I was running the demo code in this tutorial langgraph-supervisor. The llm call sequence is:

[
	>> Supervisor call-1
    {
        "messages": [
            {
                "role": "system",
                "content": "You manage a hotel booking assistant and aflight booking assistant. Assign work to them."
            },
            {
                "role": "user",
                "content": "book a flight from BOS to JFK and a stay at McKittrick Hotel"
            },
            {
                "role": "assistant",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "chatcmpl-tool-717c2125c38b4848a0f3a5f951759228",
                        "function": {
                            "name": "transfer_to_flight_assistant",
                            "arguments": "{}"
                        }
                    },
                    {
                        "type": "function",
                        "id": "chatcmpl-tool-9ebfde044b51449487708820a16bcf51",
                        "function": {
                            "name": "transfer_to_hotel_assistant",
                            "arguments": "{\"hotel_name\": \"McKittrick Hotel\"}"
                        }
                    }
                ],
                "content": "\n\n"
            }
        ],
        "tools": [
            {
                "type": "function",
                "function": {
                    "name": "transfer_to_hotel_assistant",
                    "description": "Ask agent 'hotel_assistant' for help",
                    "parameters": {
                        "properties": {},
                        "type": "object"
                    }
                }
            },
            {
                "type": "function",
                "function": {
                    "name": "transfer_to_flight_assistant",
                    "description": "Ask agent 'flight_assistant' for help",
                    "parameters": {
                        "properties": {},
                        "type": "object"
                    }
                }
            }
        ]
    },
	>> Hotel-agent call-1
    {
        "messages": [
            {
                "role": "system",
                "content": "You are a hotel booking assistant"
            },
            {
                "role": "user",
                "content": "book a flight from BOS to JFK and a stay at McKittrick Hotel"
            },
            {
                "role": "assistant",
                "name": "supervisor",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "chatcmpl-tool-9ebfde044b51449487708820a16bcf51",
                        "function": {
                            "name": "transfer_to_hotel_assistant",
                            "arguments": "{\"hotel_name\": \"McKittrick Hotel\"}"
                        }
                    }
                ],
                "content": "\n\n"
            },
            {
                "role": "tool",
                "name": "transfer_to_hotel_assistant",
                "tool_call_id": "chatcmpl-tool-9ebfde044b51449487708820a16bcf51",
                "content": "Successfully transferred to hotel_assistant"
            },
            {
                "role": "assistant",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "chatcmpl-tool-15e66d7d5dcf4f7982d463eb5a4a7941",
                        "function": {
                            "name": "transfer_to_flight_assistant",
                            "arguments": "{\"flight_from\": \"BOS\", \"flight_to\": \"JFK\"}"
                        }
                    }
                ],
                "content": "<think>\n"
            }
        ],
        "tools": [
            {
                "type": "function",
                "function": {
                    "name": "book_hotel",
                    "description": "Book a hotel",
                    "parameters": {
                        "properties": {
                            "hotel_name": {
                                "type": "string"
                            }
                        },
                        "required": [
                            "hotel_name"
                        ],
                        "type": "object"
                    }
                }
            }
        ]
    },
	>> Hotel-agent call-2
    {
        "messages": [
            {
                "role": "system",
                "content": "You are a hotel booking assistant"
            },
            {
                "role": "user",
                "content": "book a flight from BOS to JFK and a stay at McKittrick Hotel"
            },
            {
                "role": "assistant",
                "name": "supervisor",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "chatcmpl-tool-9ebfde044b51449487708820a16bcf51",
                        "function": {
                            "name": "transfer_to_hotel_assistant",
                            "arguments": "{\"hotel_name\": \"McKittrick Hotel\"}"
                        }
                    }
                ],
                "content": "\n\n"
            },
            {
                "role": "tool",
                "name": "transfer_to_hotel_assistant",
                "tool_call_id": "chatcmpl-tool-9ebfde044b51449487708820a16bcf51",
                "content": "Successfully transferred to hotel_assistant"
            },
            {
                "role": "assistant",
                "name": "hotel_assistant",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "chatcmpl-tool-15e66d7d5dcf4f7982d463eb5a4a7941",
                        "function": {
                            "name": "transfer_to_flight_assistant",
                            "arguments": "{\"flight_from\": \"BOS\", \"flight_to\": \"JFK\"}"
                        }
                    }
                ],
                "content": "<think>\n"
            },
            {
                "role": "tool",
                "name": "transfer_to_flight_assistant",
                "tool_call_id": "chatcmpl-tool-15e66d7d5dcf4f7982d463eb5a4a7941",
                "content": "Error: transfer_to_flight_assistant is not a valid tool, try one of [book_hotel]."
            },
            {
                "role": "assistant",
                "content": "<think>\nOkay, the user tried to book a flight and a hotel, but the tools only have the book_hotel function. So, I need to inform them that I can only book a hotel. Let me check again to make sure there's no other function I missed. No, the provided tools only include book_hotel. So, I should clarify that I can't handle flight bookings and suggest they use another service. Keep the response helpful and clear."
            }
        ],
        "tools": [
            {
                "type": "function",
                "function": {
                    "name": "book_hotel",
                    "description": "Book a hotel",
                    "parameters": {
                        "properties": {
                            "hotel_name": {
                                "type": "string"
                            }
                        },
                        "required": [
                            "hotel_name"
                        ],
                        "type": "object"
                    }
                }
            }
        ]
    },
	>> Supervisor call-2
    {
        "messages": [
            {
                "role": "system",
                "content": "You manage a hotel booking assistant and aflight booking assistant. Assign work to them."
            },
            {
                "role": "user",
                "content": "book a flight from BOS to JFK and a stay at McKittrick Hotel"
            },
            {
                "role": "assistant",
                "name": "hotel_assistant",
                "content": "<think>\nOkay, the user tried to book a flight and a hotel, but the tools only have the book_hotel function. So, I need to inform them that I can only book a hotel. Let me check again to make sure there's no other function I missed. No, the provided tools only include book_hotel. So, I should clarify that I can't handle flight bookings and suggest they use another service. Keep the response helpful and clear."
            },
            {
                "role": "assistant",
                "name": "hotel_assistant",
                "tool_calls": [
                    {
                        "type": "function",
                        "id": "a6fe8265-7680-4ffe-9ca2-cbe5ac8950d8",
                        "function": {
                            "name": "transfer_back_to_supervisor",
                            "arguments": "{}"
                        }
                    }
                ],
                "content": "Transferring back to supervisor"
            },
            {
                "role": "tool",
                "name": "transfer_back_to_supervisor",
                "tool_call_id": "a6fe8265-7680-4ffe-9ca2-cbe5ac8950d8",
                "content": "Successfully transferred back to supervisor"
            },
            {
                "role": "assistant",
                "content": "\n\nI can only assist with hotel bookings. If you need help with that, feel free to ask!"
            }
        ],
        "tools": [
            {
                "type": "function",
                "function": {
                    "name": "transfer_to_hotel_assistant",
                    "description": "Ask agent 'hotel_assistant' for help",
                    "parameters": {
                        "properties": {},
                        "type": "object"
                    }
                }
            },
            {
                "type": "function",
                "function": {
                    "name": "transfer_to_flight_assistant",
                    "description": "Ask agent 'flight_assistant' for help",
                    "parameters": {
                        "properties": {},
                        "type": "object"
                    }
                }
            }
        ]
    }
]

which doesn't correspond to what is shown in this picture.