run-llama/llama_index · error · ValueError

Got a larger chunk overlap ({chunk_overlap}) than chunk size

Error message

Got a larger chunk overlap ({chunk_overlap}) than chunk size ({chunk_size}), should be smaller.

What it means

Error "Got a larger chunk overlap ({chunk_overlap}) than chunk size ({chunk_size}), should be smaller." thrown in run-llama/llama_index.

Source

Thrown at llama-index-core/llama_index/core/node_parser/text/sentence.py:84

    _sub_sentence_split_fns: List[Callable] = PrivateAttr()

    def __init__(
        self,
        separator: str = " ",
        chunk_size: int = DEFAULT_CHUNK_SIZE,
        chunk_overlap: int = SENTENCE_CHUNK_OVERLAP,
        tokenizer: Optional[Callable] = None,
        paragraph_separator: str = DEFAULT_PARAGRAPH_SEP,
        chunking_tokenizer_fn: Optional[Callable[[str], List[str]]] = None,
        secondary_chunking_regex: Optional[str] = CHUNKING_REGEX,
        callback_manager: Optional[CallbackManager] = None,
        include_metadata: bool = True,
        include_prev_next_rel: bool = True,
        id_func: Optional[Callable] = None,
    ):
        """Initialize with parameters."""
        if chunk_overlap > chunk_size:
            raise ValueError(
                f"Got a larger chunk overlap ({chunk_overlap}) than chunk size "
                f"({chunk_size}), should be smaller."
            )
        id_func = id_func or default_id_func
        callback_manager = callback_manager or CallbackManager([])
        super().__init__(
            chunk_size=chunk_size,
            chunk_overlap=chunk_overlap,
            secondary_chunking_regex=secondary_chunking_regex,
            separator=separator,
            paragraph_separator=paragraph_separator,
            callback_manager=callback_manager,
            include_metadata=include_metadata,
            include_prev_next_rel=include_prev_next_rel,
            id_func=id_func,
        )
        self._chunking_tokenizer_fn = (
            chunking_tokenizer_fn or split_by_sentence_tokenizer()

View on GitHub (pinned to afd0fef371)

Solutions

1. Set chunk_overlap smaller than chunk_size.
2. Increase chunk_size or decrease chunk_overlap in SentenceSplitter.

When it happens

Trigger: Thrown at llama-index-core/llama_index/core/node_parser/text/sentence.py:84 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/a972dbc02d0538f5. Report an issue: GitHub.