What causes "Output file id is None cannot retrieve file content" in BerriAI/litellm?

Poll until batch.status == 'completed' before retrieving output content.

BerriAI/litellm · error · ValueError

Output file id is None cannot retrieve file content

Error message

Output file id is None cannot retrieve file content

What it means

ValueError raised by the batches utility that retrieves a batch's output file content when batch.output_file_id is None. OpenAI only populates output_file_id once a batch reaches a terminal state with results; if you try to fetch results before the batch has completed (or for a failed/expired batch), there is no output file to retrieve and LiteLLM fails fast.

Source

Thrown at litellm/batches/batch_utils.py:254

    custom_llm_provider: Literal["openai", "azure", "vertex_ai", "hosted_vllm", "anthropic"] = "openai",
    litellm_params: dict | None = None,
) -> bytes:
    """
    Fetch the batch output file and return its raw JSONL bytes

    Args:
        batch: The batch object
        custom_llm_provider: The LLM provider
        litellm_params: Optional litellm parameters containing credentials (api_key, api_base, etc.)
                       Required for Azure and other providers that need authentication
    """
    from litellm.files.main import afile_content
    from litellm.proxy.openai_files_endpoints.common_utils import (
        _is_base64_encoded_unified_file_id,
    )

    if batch.output_file_id is None:
        raise ValueError("Output file id is None cannot retrieve file content")

    file_id = batch.output_file_id
    is_base64_unified_file_id: Final = _is_base64_encoded_unified_file_id(file_id)
    if is_base64_unified_file_id:
        try:
            file_id = is_base64_unified_file_id.split("llm_output_file_id,")[1].split(";")[0]
            verbose_logger.debug("Extracted LLM output file ID from unified file ID: %s", file_id)
        except (IndexError, AttributeError) as e:
            verbose_logger.error(
                "Failed to extract LLM output file ID from unified file ID: %s, error: %s", batch.output_file_id, e
            )

    # Build kwargs for afile_content with credentials from litellm_params
    file_content_kwargs: Final = {
        "file_id": file_id,
        "custom_llm_provider": custom_llm_provider,
    }

View on GitHub (pinned to 6c2dcb801b)

Solutions

Poll until batch.status == 'completed' before retrieving output content.
If the batch failed or was cancelled, read batch.error_file_id / errors instead — output_file_id stays None.
Guard the call: if batch.output_file_id is None: skip/handle.

Example fix

# before
content = await afile_content(batch.output_file_id, ...)

# after
if batch.output_file_id is None:
    raise RuntimeError(f"Batch {batch.id} not completed (status={batch.status}); no output file yet")
content = await afile_content(batch.output_file_id, ...)

Defensive patterns

Strategy: validation

Validate before calling

if batch.output_file_id is None:
    raise RuntimeError(f"Batch {batch.id} status={batch.status}: no output file available")

Type guard

def batch_has_output(batch) -> bool:
    return getattr(batch, "output_file_id", None) is not None

Try / catch

try:
    content = await afile_content(batch.output_file_id, ...)
except ValueError as e:
    if "Output file id is None" in str(e):
        logger.warning("batch %s not ready (status=%s)", batch.id, batch.status)
        content = None
    else:
        raise

Prevention

Gate output retrieval on batch.status == 'completed'.
For failed batches, use error_file_id instead.
Build polling helpers with max attempts and backoff rather than fire-and-forget fetches.

When it happens

Trigger: Calling litellm.get_batch_output_file_content (or afile_content-based retrieval) on a batch object whose output_file_id is None — typically a batch still in 'in_progress'/'validating'/'finalizing', or one that failed/cancelled/expired without producing output.

Common situations: Polling code that checks batch.status != 'completed' incorrectly and fetches too early; a failed batch (check errors_file_id instead); provider responses that omit output_file_id even on completion.

Related errors

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/df009126d3a7bd73. Report an issue: GitHub.