Support NativeOutput in FunctionModel

[janrito]

Description

Would like to have some facility to test native output pipeline in an agent.

FunctionModel currently complains that Native structured output is not supported by the model.

References

No response

[DouweM]

@janrito Sounds reasonable, let's see if Claude is up to the task:

@claude Create a PR to have FunctionModel use a ModelProfile by default that has supports_json_schema_output and supports_json_object_output set to True. You can then modify the test_agent.py::test_native_output test to no longer pass the custom profile.

[claude]

Claude finished @DouweM's task —— View job • claude/issue-2839-20250909-1529 • Create PR ➔

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FunctionModel NativeOutput support implemented!

I have successfully implemented support for NativeOutput in FunctionModel by updating it to use a ModelProfile with JSON schema output support by default.

Tasks Completed:

• Read repository guidelines (CLAUDE.md)
• Find and analyze FunctionModel implementation
• Find and analyze ModelProfile structure
• Locate test_native_output test
• Update FunctionModel to use ModelProfile with JSON support
• Update test to remove custom profile parameter
• Run tests to verify changes
• Commit and push changes

Changes Made:

1. Updated FunctionModel (pydantic_ai_slim/pydantic_ai/models/function.py:114-120):
   • Added default ModelProfile with supports_json_schema_output=True and supports_json_object_output=True when no profile is provided
   • Added import for ModelProfile
2. Updated test_native_output (tests/test_agent.py:1560):
   • Removed the custom profile parameter since FunctionModel now provides the needed profile by default

Verification Results:

✅ All specific tests pass (test_native_output and entire test_agent.py suite)
✅ All FunctionModel tests pass (test_model_function.py)
✅ Pre-commit checks pass (linting, formatting, type checking)
✅ Manual verification confirms FunctionModel now supports NativeOutput by default

FunctionModel now supports NativeOutput without requiring a custom profile! This enables easy testing of the native output pipeline in agents as requested in the issue.

[janrito]

Amazing!