fix: handle Field(default_factory=...) in @tool decorator without warning#2200
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luyao618 wants to merge 1 commit intostrands-agents:mainfrom
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fix: handle Field(default_factory=...) in @tool decorator without warning#2200luyao618 wants to merge 1 commit intostrands-agents:mainfrom
luyao618 wants to merge 1 commit intostrands-agents:mainfrom
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…ning When a @tool-decorated function uses Field(default_factory=list) as a parameter default, the decorator wraps the FieldInfo in another Field() call, producing a non-serialisable default that triggers PydanticJsonSchemaWarning. Detect when param_default is already a FieldInfo instance and extract its default/default_factory/description instead of wrapping it again. Closes strands-agents#1914
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Problem
When a
@tool-decorated function usesField(default_factory=list)as a parameter default:The decorator passes the
FieldInfoobject asdefault=<FieldInfo>into anotherField()call, producing a non-serialisable default that triggersPydanticJsonSchemaWarning.Reported in #1914.
Solution
In
_extract_annotated_metadata(), detect whenparam_defaultis already aFieldInfoinstance and extract itsdefault/default_factory/descriptionattributes to build a cleanField()instead of wrapping it again.Testing
Added two tests:
test_tool_field_default_factory_no_warning— verifies noPydanticJsonSchemaWarningis emitted and the schema is correcttest_tool_field_default_value— verifiesField(default=...)as a parameter default works correctlyCloses #1914