feat: add public tool_spec setter

[mkmeral]

Description

Add a public tool_spec setter property to DecoratedFunctionTool and PythonAgentTool, enabling runtime modification of a tool's schema after construction.

This is useful for dynamically adjusting tool configurations based on feature flags, user permissions, or other runtime conditions — for example, adding or removing parameters from a tool's input schema without recreating the tool instance.

Changes:

• src/strands/tools/decorator.py — Added @tool_spec.setter on DecoratedFunctionTool
• src/strands/tools/tools.py — Added @tool_spec.setter on PythonAgentTool
• tests/strands/tools/test_tool_spec_setter.py — 5 unit tests covering both classes

Related Issues

Documentation PR

Type of Change

New feature

Testing

Added tests/strands/tools/test_tool_spec_setter.py with 5 tests:

• TestDecoratedFunctionToolSpecSetter (3 tests): verifies spec replacement, persistence across reads, and adding properties via setter
• TestPythonAgentToolSpecSetter (2 tests): verifies spec replacement and persistence across reads

All tests pass:

tests/strands/tools/test_tool_spec_setter.py::TestDecoratedFunctionToolSpecSetter::test_set_tool_spec_replaces_spec PASSED
tests/strands/tools/test_tool_spec_setter.py::TestDecoratedFunctionToolSpecSetter::test_set_tool_spec_persists_across_reads PASSED
tests/strands/tools/test_tool_spec_setter.py::TestDecoratedFunctionToolSpecSetter::test_add_property_via_setter PASSED
tests/strands/tools/test_tool_spec_setter.py::TestPythonAgentToolSpecSetter::test_set_tool_spec PASSED
tests/strands/tools/test_tool_spec_setter.py::TestPythonAgentToolSpecSetter::test_set_tool_spec_persists PASSED

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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