FIX:Fix HttpTool config round-trip in StaticStreamWorkbench when headers is None

[yyf0101]

Why are these changes needed?

What This PR fixes a ValidationError when round-tripping a StaticStreamWorkbench containing an HttpTool created with headers=None via _to_config() / _from_config() .

Why Component.dump_component() serializes configs with exclude_none=True , which drops fields whose value is None . HttpToolConfig.headers was annotated as Optional[...] but had no default, making it required under Pydantic v2. As a result, the serialized config omitted headers , and loading failed with: headers: Field required [type=missing] .

Changes

• Set defaults in HttpToolConfig :

  • headers: Optional[dict[str, Any]] = None
  • description: Optional[str] = None (consistency with “optional” semantics)

• Add regression test to ensure workbench config round-trip works when headers is None .
  Tests

• python -m pytest packages/autogen-ext/tests/tools/http/test_http_tool.py -k test_workbench_from_config_with_missing_headers_field

Related issue number

Closes #7172

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[yyf0101]

@microsoft-github-policy-service agree

[yyf0101]

@ekzhu hi Eric ,could you please take a look at this PR (fix for #7172)? When an HttpTool is created with headers=None and put into a StaticStreamWorkbench , dump_component() uses exclude_none=True and drops headers from the serialized config, then _from_config() fails under Pydantic v2 with headers missing . This breaks workbench save/restore and config round-trips. The PR makes HttpToolConfig.headers default to None (so missing is OK) and adds a regression test for the round-trip. Thanks!