langchain-ai/langgraph · error · RuntimeError

thread.run.respond: no outstanding interrupt. Provide an exp

Error message

thread.run.respond: no outstanding interrupt. Provide an explicit `interrupt_id` or wait for `thread.interrupted`.

What it means

Error "thread.run.respond: no outstanding interrupt. Provide an explicit `interrupt_id` or wait for `thread.interrupted`." thrown in langchain-ai/langgraph.

Source

Thrown at libs/sdk-py/langgraph_sdk/_sync/stream.py:255

        *,
        interrupt_id: str | None = None,
    ) -> dict[str, Any]:
        """Reply to a server-side interrupt and resume the run.

        Args:
            response: the response value forwarded as `params.response` on the wire.
            interrupt_id: optional explicit id. When omitted, requires exactly one
                outstanding interrupt.

        Raises:
            RuntimeError: no outstanding interrupts; `interrupt_id` is None but
                multiple interrupts are outstanding; or the explicit `interrupt_id`
                doesn't match any outstanding interrupt.
        """
        outstanding = self._owner.interrupts
        if interrupt_id is None:
            if len(outstanding) == 0:
                raise RuntimeError(
                    "thread.run.respond: no outstanding interrupt. Provide an "
                    "explicit `interrupt_id` or wait for `thread.interrupted`."
                )
            if len(outstanding) > 1:
                ids = [p["interrupt_id"] for p in outstanding]
                raise RuntimeError(
                    f"thread.run.respond: ambiguous — {len(outstanding)} "
                    f"outstanding interrupts ({ids!r}). Provide an explicit "
                    "`interrupt_id`."
                )
            match = outstanding[0]
        else:
            match = next(
                (p for p in outstanding if p["interrupt_id"] == interrupt_id),
                None,
            )
            if match is None:
                raise RuntimeError(

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/sdk-py/langgraph_sdk/_sync/stream.py:255 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/cadbfa9e093350fc. Report an issue: GitHub.