agentscope-ai/agentscope · error · ValueError

Unsupported image source type: {type(source)}

Error message

Unsupported image source type: {type(source)}

What it means

The DashScope (Qwen) formatter builds an OpenAI-style image_url payload and only handles supported image source types (inline base64/local file -> data URL, and URL sources). Any other source object (None, dict, custom class) raises this ValueError before the request is sent.

Source

Thrown at src/agentscope/formatter/_dashscope_formatter.py:135

    ) -> dict[str, Any]:
        """Convert an image source to OpenAI-compatible ``image_url`` format.

        Local ``file://`` URLs are read from disk and converted to base64
        data URIs. Remote URLs are passed through unchanged.
        """
        if isinstance(source, Base64Source):
            url = f"data:{source.media_type};base64,{source.data}"
        elif isinstance(source, URLSource):
            url_str = str(source.url)
            if url_str.startswith("file://"):
                local_path = url_str.removeprefix("file://")
                with open(local_path, "rb") as f:
                    encoded = base64.b64encode(f.read()).decode("utf-8")
                url = f"data:{source.media_type};base64,{encoded}"
            else:
                url = url_str
        else:
            raise ValueError(f"Unsupported image source type: {type(source)}")

        return {
            "type": "image_url",
            "image_url": {"url": url},
        }

    @staticmethod
    def _format_video_source(
        source: URLSource | Base64Source,
    ) -> dict[str, Any]:
        """Convert a video source to DashScope's ``video_url`` format
        (OpenAI-compatible extension).

        Local ``file://`` URLs are read from disk and converted to base64
        data URIs. Remote URLs are passed through unchanged.
        """
        if isinstance(source, Base64Source):
            url = f"data:{source.media_type};base64,{source.data}"

View on GitHub (pinned to e90f1c7592)

Solutions

1. Ensure one agentscope version is installed and DataBlock sources come from agentscope.message
2. Convert images to URLSource or Base64Source before adding to the message
3. Validate blocks before sending (see type guard below)

Example fix

# before
block = DataBlock(source=None, media_type="image/png")

# after
from agentscope.message import DataBlock, URLSource
block = DataBlock(source=URLSource(url=img_url, media_type="image/png"))

from agentscope.message import Base64Source, URLSource
for block in msg_image_blocks:
    if not isinstance(getattr(block, "source", None), (Base64Source, URLSource)):
        raise TypeError("image block source unsupported")

from agentscope.message import DataBlock, Base64Source, URLSource

def image_block_ok(block: DataBlock) -> bool:
    return isinstance(getattr(block, "source", None), (Base64Source, URLSource))

try:
    resp = await model(msg)
except ValueError as e:
    if "Unsupported image source type" in str(e):
        msg = normalize_image_blocks(msg)
        resp = await model(msg)
    else:
        raise

When it happens

Trigger: Passing a message with an image DataBlock whose source is an unrecognized type; _format_dashscope_data_block -> _format_image_source falls to the final else.

Common situations: Version mismatch producing isinstance failures; building image blocks with raw dicts from JSON payloads; empty DataBlock with source=None from failed downloads.

Related errors

• Unsupported video source type: {type(source)}
• Unsupported source type: {type(source)}
• Unsupported audio source type: {type(source)}
• Unsupported image source type: {type(source)}
• Unsupported source type: {type(source)}

AI-assisted analysis of agentscope-ai/agentscope@e90f1c7592 (2026-08-28). Data as JSON: /api/errors/2c557026eb040a23. Report an issue: GitHub.