AutoGen adapter: converting a tool with an untyped input property raises KeyError: 'type'

Description

The AutoGen adapter fails to convert any tool whose input property has no type in its JSON schema. A property without type is valid Agent Spec and means "any value" (Property(json_schema={"title": "anything"})), and the LangGraph and Agent Framework adapters accept it.

Reproduction

from pyagentspec.adapters.autogen import AgentSpecLoader
from pyagentspec.property import Property, StringProperty
from pyagentspec.tools import ServerTool
from typing import Any

echo_tool = ServerTool(
    name="echo",
    description="Echoes any value as a string",
    inputs=[Property(json_schema={"title": "anything"})],
    outputs=[StringProperty(title="echoed")],
)

def echo(anything: Any) -> str:
    return str(anything)

AgentSpecLoader(tool_registry={"echo": echo}).load_component(echo_tool)

  File ".../pyagentspec/adapters/autogen/_autogenconverter.py", line 78, in _json_schema_type_to_python_annotation
    if isinstance(json_schema["type"], list):
KeyError: 'type'

Expected behavior

The tool converts, with the untyped input annotated as Any (and an array without items as List[Any]), as the Agent Framework converter already does.

Root cause

_json_schema_type_to_python_annotation in pyagentspec/src/pyagentspec/adapters/autogen/_autogenconverter.py indexes json_schema["type"] (and json_schema["items"]) directly instead of using .get().

Environment

• pyagentspec main (26.4.0.dev0), autogen-core 0.7.4, Python 3.12

Start in pyagentspec/src/pyagentspec/adapters/autogen/_autogenconverter.py, at _json_schema_type_to_python_annotation, and run the reproduction from the issue with a property missing type. Done means the AutoGen adapter converts that input as Any and an array without items as List[Any], without raising KeyError.