langchain-ai/langgraph · error · ValueError

INVALID_CHAT_HISTORY

INVALID_CHAT_HISTORY

Error message

Found AIMessages with tool_calls that do not have a corresponding ToolMessage. Here are the first few of those tool calls: {first3}. Every tool call (LLM requesting to call a tool) in the message history MUST have a corresponding ToolMessage (result of a tool invocation to return to the LLM) - this is required by most LLM providers.

What it means

Error "Found AIMessages with tool_calls that do not have a corresponding ToolMessage. Here are the first few of those tool calls: {first3}. Every tool call (LLM requesting to call a tool) in the message history MUST have a corresponding ToolMessage (result of a tool invocation to return to the LLM) - this is required by most LLM providers." thrown in langchain-ai/langgraph.

Source

Thrown at libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py:271

    tool_call_ids_with_results = {
        message.tool_call_id for message in messages if isinstance(message, ToolMessage)
    }
    tool_calls_without_results = [
        tool_call
        for tool_call in all_tool_calls
        if tool_call["id"] not in tool_call_ids_with_results
    ]
    if not tool_calls_without_results:
        return

    error_message = create_error_message(
        message="Found AIMessages with tool_calls that do not have a corresponding ToolMessage. "
        f"Here are the first few of those tool calls: {tool_calls_without_results[:3]}.\n\n"
        "Every tool call (LLM requesting to call a tool) in the message history MUST have a corresponding ToolMessage "
        "(result of a tool invocation to return to the LLM) - this is required by most LLM providers.",
        error_code=ErrorCode.INVALID_CHAT_HISTORY,
    )
    raise ValueError(error_message)


@deprecated(
    "create_react_agent has been moved to `langchain.agents`. Please update your import to `from langchain.agents import create_agent`.",
    category=LangGraphDeprecatedSinceV10,
)
def create_react_agent(
    model: str
    | LanguageModelLike
    | Callable[[StateSchema, Runtime[ContextT]], BaseChatModel]
    | Callable[[StateSchema, Runtime[ContextT]], Awaitable[BaseChatModel]]
    | Callable[
        [StateSchema, Runtime[ContextT]], Runnable[LanguageModelInput, BaseMessage]
    ]
    | Callable[
        [StateSchema, Runtime[ContextT]],
        Awaitable[Runnable[LanguageModelInput, BaseMessage]],
    ],

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py:271 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of langchain-ai/langgraph@38031739e5 (2026-08-26). Data as JSON: /api/errors/e9089b22375656fc. Report an issue: GitHub.