langchain-ai/langgraph · error · ValueError

recursion_limit must be at least 1

Error message

recursion_limit must be at least 1

What it means

Error "recursion_limit must be at least 1" thrown in langchain-ai/langgraph.

Source

Thrown at libs/langgraph/langgraph/pregel/main.py:2564

        *,
        stream_mode: StreamMode | Sequence[StreamMode],
        print_mode: StreamMode | Sequence[StreamMode],
        output_keys: str | Sequence[str] | None,
        interrupt_before: All | Sequence[str] | None,
        interrupt_after: All | Sequence[str] | None,
        durability: Durability | None = None,
    ) -> tuple[
        set[StreamMode],
        str | Sequence[str],
        All | Sequence[str],
        All | Sequence[str],
        BaseCheckpointSaver | None,
        BaseStore | None,
        BaseCache | None,
        Durability,
    ]:
        if config["recursion_limit"] < 1:
            raise ValueError("recursion_limit must be at least 1")
        if output_keys is None:
            output_keys = self.stream_channels_asis
        else:
            validate_keys(output_keys, self.channels)
        interrupt_before = interrupt_before or self.interrupt_before_nodes
        interrupt_after = interrupt_after or self.interrupt_after_nodes
        if isinstance(stream_mode, str):
            stream_modes = {stream_mode}
        else:
            stream_modes = set(stream_mode)
        if isinstance(print_mode, str):
            stream_modes.add(print_mode)
        else:
            stream_modes.update(print_mode)
        if self.checkpointer is False:
            checkpointer: BaseCheckpointSaver | None = None
        elif CONFIG_KEY_CHECKPOINTER in config.get(CONF, {}):
            checkpointer = config[CONF][CONFIG_KEY_CHECKPOINTER]

View on GitHub (pinned to 38031739e5)

When it happens

Trigger: Thrown at libs/langgraph/langgraph/pregel/main.py:2564 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/bd07f3f21cabd80d. Report an issue: GitHub.