What causes "component_type not defined" in microsoft/autogen?

microsoft/autogen · error · AttributeError

component_type not defined

Error message

component_type not defined

What it means

dump_component requires the ClassVar component_type to label the ComponentModel. The implementation checks hasattr(self, 'component_type'); inheriting from ComponentToConfig/ComponentBase without setting component_type (it is declared but only as a ClassVar annotation without a default on ComponentToConfig) leaves the attribute missing, so AttributeError is raised.

Source

Thrown at python/packages/autogen-core/src/autogen_core/_component_config.py:169

        Returns:
            ComponentModel: The model representing the component.
        """
        if self.component_provider_override is not None:
            provider = self.component_provider_override
        else:
            provider = _type_to_provider_str(self.__class__)
            # Warn if internal module name is used,
            if "._" in provider:
                warnings.warn(
                    "Internal module name used in provider string. This is not recommended and may cause issues in the future. Silence this warning by setting component_provider_override to this value.",
                    stacklevel=2,
                )

        if "<locals>" in provider:
            raise TypeError("Cannot dump component with local class")

        if not hasattr(self, "component_type"):
            raise AttributeError("component_type not defined")

        description = self.component_description
        if description is None and self.__class__.__doc__:
            # use docstring as description
            docstring = self.__class__.__doc__.strip()
            for marker in ["\n\nArgs:", "\n\nParameters:", "\n\nAttributes:", "\n\n"]:
                docstring = docstring.split(marker)[0]
            description = docstring.strip()

        obj_config = self._to_config().model_dump(exclude_none=True)
        model = ComponentModel(
            provider=provider,
            component_type=self.component_type,
            version=self.component_version,
            component_version=self.component_version,
            description=description,
            label=self.component_label or self.__class__.__name__,
            config=obj_config,

View on GitHub (pinned to 027ecf0a37)

Solutions

Declare component_type on the subclass: component_type: ClassVar[ComponentType] = ComponentType.model (or the appropriate enum value).
Also set component_version (defaults to 1) and optionally component_description/label.
Add a trivial test that calls dump_component() to catch missing metadata early.

Example fix

# before
class MyComp(ComponentToConfig):
    def _to_config(self) -> MyConfig: ...
# MyComp().dump_component() -> AttributeError

# after
from autogen_core import ComponentType

class MyComp(ComponentToConfig):
    component_type: ClassVar[ComponentType] = ComponentType.model
    component_version: ClassVar[int] = 1

    def _to_config(self) -> MyConfig: ...

Defensive patterns

Strategy: validation

Validate before calling

if not hasattr(MyComp, "component_type"):
    raise TypeError("set component_type: ClassVar[ComponentType] on the subclass")

Type guard

def has_component_type(cls: type) -> bool:
    return hasattr(cls, "component_type") and cls.component_type is not None

Try / catch

try:
    model = comp.dump_component()
except AttributeError as e:
    if "component_type" in str(e):
        # add the missing ClassVar and retry
        raise
    raise

Prevention

Declare component_type (and component_version) on every component subclass.
Write a tiny pytest that calls dump_component() for each registered component.
Use a shared base class in your project that enforces the metadata.

When it happens

Trigger: class MyComp(ComponentToConfig): pass (no component_type assignment) then MyComp().dump_component(); overriding component_type with None; typos like component_typ.

Common situations: Minimal component subclasses written from examples that omit the field; copy-paste from a protocol stub; subclasses that delete the attribute.

Related errors

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/6cbbdcffdec44808. Report an issue: GitHub.