BerriAI/litellm · error · ValueError

Bedrock batch embedding `input` must be a string (or a singl

Error message

Bedrock batch embedding `input` must be a string (or a single-element list of strings). Got type {type(candidate).__name__} for model={model}.

What it means

Error "Bedrock batch embedding `input` must be a string (or a single-element list of strings). Got type {type(candidate).__name__} for model={model}." thrown in BerriAI/litellm.

Source

Thrown at litellm/llms/bedrock/files/transformation.py:578

                    "record. Got a list with "
                    f"{len(raw_input)} items for model={model}; emit one "
                    "JSONL line per input string instead."
                )
        else:
            candidate = raw_input

        # Catches pre-tokenized inputs (List[int] from OpenAI spec, or a
        # single int slipping past the list-unwrap above).
        # NOTE: bool is a subclass of int but treating True/False as a token
        # is meaningless either way, so the broad check is fine.
        if isinstance(candidate, (list, int)):
            raise NotImplementedError(
                "Bedrock Titan v2 batch embedding does not support "
                "pre-tokenized integer inputs. Pass `input` as a string "
                f"(model={model})."
            )
        if not isinstance(candidate, str):
            raise ValueError(
                "Bedrock batch embedding `input` must be a string (or a "
                "single-element list of strings). Got type "
                f"{type(candidate).__name__} for model={model}."
            )
        return candidate

    def _map_openai_embedding_to_bedrock_params(
        self,
        openai_request_body: _OpenAIBatchRecordBody,
        model: str,
    ) -> dict[str, object]:
        """
        Transform an OpenAI /v1/embeddings request body into the
        Bedrock InvokeModel `modelInput` for embedding models that AWS
        supports via batch inference (CreateModelInvocationJob).

        Currently routes Amazon Titan Text Embeddings V2 only; other
        embedding providers (Titan G1, Titan Multimodal, Cohere Embed,

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Pass `input` as a string or a single-element list of strings.

When it happens

Trigger: Thrown at litellm/llms/bedrock/files/transformation.py:578 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/38cd0e726c0aad7a. Report an issue: GitHub.