docling-project/docling · error · ValueError

Unsupported VLM inference framework: {vlm_options.inference_

Error message

Unsupported VLM inference framework: {vlm_options.inference_framework}

What it means

ValueError raised while building the VLM model inside ThreadedLayoutVlmPipeline: vlm_options.inference_framework is not one of the frameworks the pipeline knows how to instantiate (the elif chain covers only specific InferenceFramework members such as TRANSFORMERS and VLLM).

Source

Thrown at docling/experimental/pipeline/threaded_layout_vlm_pipeline.py:208

                )
            elif vlm_options.inference_framework == InferenceFramework.MLX:
                self.vlm_model = HuggingFaceMlxModel(
                    enabled=True,
                    artifacts_path=art_path,
                    accelerator_options=self.pipeline_options.accelerator_options,
                    vlm_options=vlm_options,
                )
            elif vlm_options.inference_framework == InferenceFramework.VLLM:
                from docling.models.vlm_pipeline_models.vllm_model import VllmVlmModel

                self.vlm_model = VllmVlmModel(
                    enabled=True,
                    artifacts_path=art_path,
                    accelerator_options=self.pipeline_options.accelerator_options,
                    vlm_options=vlm_options,
                )
            else:
                raise ValueError(
                    f"Unsupported VLM inference framework: {vlm_options.inference_framework}"
                )
        else:
            raise ValueError(f"Unsupported VLM options type: {type(base_vlm_options)}")

    def _resolve_artifacts_path(self) -> Optional[Path]:
        """Resolve artifacts path from options or settings."""
        if self.pipeline_options.artifacts_path:
            p = Path(self.pipeline_options.artifacts_path).expanduser()
        elif settings.artifacts_path:
            p = Path(settings.artifacts_path).expanduser()
        else:
            return None
        if not p.is_dir():
            raise RuntimeError(
                f"{p} does not exist or is not a directory containing the required models"
            )
        return p

View on GitHub (pinned to 61d76f1ff3)

Solutions

1. Use one of the frameworks supported by the threaded pipeline, e.g. InferenceFramework.VLLM or the local transformers-based one shown in the branch above.
2. If you need API-based inference, use the standard VlmPipeline with StandardPdfPipeline instead.
3. Pin/align Docling versions so the enum values you reference match what the pipeline implements.

Example fix

# before
vlm_opts.inference_framework = InferenceFramework.API  # not implemented here

# after
vlm_opts.inference_framework = InferenceFramework.VLLM
# (or use StandardPdfPipeline + VlmPipeline for API-backed inference)

from docling.datamodel.pipeline_options_vlm_model import InferenceFramework
SUPPORTED = {InferenceFramework.TRANSFORMERS, InferenceFramework.VLLM}
assert vlm_opts.inference_framework in SUPPORTED, 'threaded pipeline supports local frameworks only'

def is_supported_framework(fw: InferenceFramework) -> bool:
    return fw in {InferenceFramework.TRANSFORMERS, InferenceFramework.VLLM}

try:
    pipeline = ThreadedLayoutVlmPipeline(opts)
except ValueError as e:
    if 'Unsupported VLM inference framework' in str(e):
        vlm_opts.inference_framework = InferenceFramework.VLLM
        pipeline = ThreadedLayoutVlmPipeline(opts)

When it happens

Trigger: Setting ThreadedLayoutVlmPipelineOptions.vlm_options.inference_framework to a framework not handled by this pipeline (e.g. an API/remote framework enum value) and then initializing the pipeline.

Common situations: Reusing options written for the standard VlmPipeline which supports remote-API inference frameworks; enum gains new members in a newer Docling version that the experimental threaded pipeline has not adopted yet.

Related errors

• Could not instantiate the right type of VLM pipeline: {vlm_o
• {p} does not exist or is not a directory containing the requ
• Model '{repo_id}' not found in artifacts_path. Expected loca
• Unknown prompt style: {prompt_style}. Valid values are {', '
• Connections to remote services is only allowed when set expl

AI-assisted analysis of docling-project/docling@61d76f1ff3 (2026-08-14). Data as JSON: /api/errors/0e014b8e259d1b7e. Report an issue: GitHub.