BerriAI/litellm · error · Exception

Unknown file type. Please pass in a file_id or file_data

Error message

Unknown file type. Please pass in a file_id or file_data

What it means

Guard in Gemini content conversion: a message part claims to be a file but carries neither file_id nor file_data (and no recognizable mime/URL payload), so there is no way to resolve the bytes and the conversion aborts.

Source

Thrown at litellm/llms/vertex_ai/gemini/transformation.py:820

                            if _file_field is None:
                                raise litellm.BadRequestError(
                                    message="Content block has type='file' but is missing the required 'file' field",
                                    model=model,
                                    llm_provider="vertex_ai",
                                )
                            # TypedDict does not declare mime_type/content_type;
                            # read via Dict[str, Any] for caller-provided MIME fields.
                            file_dict = cast(dict[str, Any], _file_field)
                            file_id = file_dict.get("file_id")
                            format = (
                                file_dict.get("format") or file_dict.get("mime_type") or file_dict.get("content_type")
                            )
                            file_data = file_dict.get("file_data")
                            detail = file_dict.get("detail")
                            video_metadata = file_dict.get("video_metadata")
                            passed_file = file_id or file_data
                            if passed_file is None:
                                raise Exception("Unknown file type. Please pass in a file_id or file_data")

                            # Convert detail to media_resolution_enum
                            media_resolution_enum = _convert_detail_to_media_resolution_enum(detail)

                            try:
                                _part = _process_gemini_media(
                                    image_url=passed_file,
                                    format=format,
                                    model=model,
                                    media_resolution_enum=media_resolution_enum,
                                    video_metadata=video_metadata,
                                    vertex_project=vertex_project,
                                    vertex_credentials=vertex_credentials,
                                )
                                _parts.append(_part)
                            except litellm.BadRequestError:
                                raise
                            except Exception as e:

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Pass file_id or file_data for the file content in the message.
2. Check the file part structure in the messages payload.

Example fix

# include {"file_data": ...} or {"file_id": ...} in the file part.

When it happens

Trigger: Triggered when a file message part has neither file_id nor file_data.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/365018e5ed84b414. Report an issue: GitHub.