Fixes #2949

Problem

The module-level docstring in src/agents/extensions/handoff_filters.py:

"""Contains common handoff input filters, for convenience. """

was placed after all the import statements. In Python, only a string literal that is the very first statement of a module is treated as the module docstring and assigned to __doc__. Any string literal appearing after other statements is discarded as an expression and never bound to __doc__.

# Before fix
import agents.extensions.handoff_filters as m
print(m.__doc__)  # None

This causes confusion for IDEs, help(), and documentation generators.

Fix

Move the docstring to the very top of the file (before all imports), where Python expects it.

# After fix
import agents.extensions.handoff_filters as m
print(m.__doc__)  # "Contains common handoff input filters, for convenience."

Changes

• src/agents/extensions/handoff_filters.py: Move module docstring to before imports; remove trailing space from docstring.