NousResearch/hermes-agent · error · ValueError

Unknown input block type: {kind!r}

Error message

Unknown input block type: {kind!r}

What it means

Error "Unknown input block type: {kind!r}" thrown in NousResearch/hermes-agent.

Source

Thrown at agent/plugin_llm.py:481

        return d
    if isinstance(block, dict):
        kind = block.get("type")
        if kind == "text":
            text = block.get("text")
            if not isinstance(text, str):
                raise ValueError("text input block requires 'text' string")
            return {"type": "text", "text": text}
        if kind == "image":
            if "data" not in block and not block.get("url"):
                raise ValueError("image input block requires 'data' bytes or 'url'")
            return {
                "type": "image",
                "data": block.get("data"),
                "url": block.get("url"),
                "mime_type": block.get("mime_type") or "image/png",
                "file_name": block.get("file_name") or "",
            }
        raise ValueError(f"Unknown input block type: {kind!r}")
    raise ValueError(f"Unsupported input block: {type(block).__name__}")


def _build_structured_messages(
    *,
    instructions: str,
    inputs: Sequence[PluginLlmInput],
    json_mode: bool,
    json_schema: Optional[Any],
    schema_name: Optional[str],
    system_prompt: Optional[str],
) -> List[Dict[str, Any]]:
    """Build the OpenAI-style messages list for a structured call.

    The instructions become the first text part of the user message,
    followed by an optional ``Schema name: <name>`` hint and an optional
    JSON-only directive when JSON output is requested. Image inputs are
    encoded as ``image_url`` parts.

View on GitHub (pinned to c896c09c42)

Solutions

  1. Use a supported input block type (text or image).
  2. Fix the plugin code that emitted the unknown block kind.

When it happens

Trigger: Thrown at agent/plugin_llm.py:481 when the library encounters an invalid state.

Common situations: See trigger scenarios.


AI-assisted analysis of NousResearch/hermes-agent@c896c09c42 (2026-08-14). Data as JSON: /api/errors/0c617bf2afcd8b17. Report an issue: GitHub.