run-llama/llama_index · error · ValueError

Invalid mode: {v}

Error message

Invalid mode: {v}

What it means

Error "Invalid mode: {v}" thrown in run-llama/llama_index.

Source

Thrown at llama-index-core/llama_index/core/postprocessor/node.py:175

    Args:
        docstore (BaseDocumentStore): The document store.
        num_nodes (int): The number of nodes to return (default: 1)
        mode (str): The mode of the post-processor.
            Can be "previous", "next", or "both.

    """

    docstore: BaseDocumentStore
    num_nodes: int = Field(default=1)
    mode: str = Field(default="next")

    @field_validator("mode")
    @classmethod
    def _validate_mode(cls, v: str) -> str:
        """Validate mode."""
        if v not in ["next", "previous", "both"]:
            raise ValueError(f"Invalid mode: {v}")
        return v

    @classmethod
    def class_name(cls) -> str:
        return "PrevNextNodePostprocessor"

    def _postprocess_nodes(
        self,
        nodes: List[NodeWithScore],
        query_bundle: Optional[QueryBundle] = None,
    ) -> List[NodeWithScore]:
        """Postprocess nodes."""
        all_nodes: Dict[str, NodeWithScore] = {}
        for node in nodes:
            all_nodes[node.node.node_id] = node
            if self.mode == "next":
                all_nodes.update(get_forward_nodes(node, self.num_nodes, self.docstore))
            elif self.mode == "previous":

View on GitHub (pinned to afd0fef371)

Solutions

1. Use a valid mode value for the postprocessor (check the class's allowed modes).
2. Correct the mode argument passed to the constructor.

When it happens

Trigger: Thrown at llama-index-core/llama_index/core/postprocessor/node.py:175 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of run-llama/llama_index@afd0fef371 (2026-08-15). Data as JSON: /api/errors/718f3a86e7d01744. Report an issue: GitHub.