DynamicToolRegistry stored getattr(tool_class, 'description'), which for a
class-level @property returns the property DESCRIPTOR (not a str). 'tool list'
then did len(config.description) → 'object of type property has no len()',
breaking the entire tool-catalog command. Add _extract_tool_description
(mirrors _extract_tool_name): resolve a @property via a cheap instance, else
coerce to str, always returns str. Plus a defensive isinstance guard in the
list display path. Regression test covers property/unevaluable-property/plain/
absent + asserts every registered entry's description is len()-safe. 2 passed.