langchain-ai/langgraph · error · ValueError

response_format must be 'array' or 'object'

Error message

response_format must be 'array' or 'object'

What it means

Error "response_format must be 'array' or 'object'" thrown in langchain-ai/langgraph.

Source

Thrown at libs/sdk-py/langgraph_sdk/_sync/assistants.py:585

            `response_format="object"`).

        ???+ example "Example Usage"

            ```python
            client = get_sync_client(url="http://localhost:2024")
            response = client.assistants.search(
                metadata = {"name":"my_name"},
                graph_id="my_graph_id",
                limit=5,
                offset=5,
                response_format="object",
            )
            assistants = response["assistants"]
            next_cursor = response["next"]
            ```
        """
        if response_format not in ("array", "object"):
            raise ValueError("response_format must be 'array' or 'object'")
        payload: dict[str, Any] = {
            "limit": limit,
            "offset": offset,
        }
        if metadata:
            payload["metadata"] = metadata
        if graph_id:
            payload["graph_id"] = graph_id
        if name:
            payload["name"] = name
        if sort_by:
            payload["sort_by"] = sort_by
        if sort_order:
            payload["sort_order"] = sort_order
        if select:
            payload["select"] = select
        next_cursor: str | None = None

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/sdk-py/langgraph_sdk/_sync/assistants.py:585 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/81e448c82049f46b. Report an issue: GitHub.