feat: Add default parameter values support for tool definitions #90

[baonudesifeizhai]

• Add parameter_defaults field to ToolFunctionDef and ToolFunctionDefDict
• Implement automatic default extraction from function signatures using inspect
• Add manual default specification support
• Update JSON schema generation to include default values
• Add comprehensive test coverage for default parameter values
• Maintain backward compatibility with existing tool definitions

Closes #90

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[baonudesifeizhai]

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[baonudesifeizhai]

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[ncoghlan]

Thank you for this!

I think we should go for an inline default format using the same style as Zod in TypeScript, as well as JSON schema itself, allowing the type fields to contain {"type": some_type, "default": some_value} instead of simply the type annotation. At the same time, we can tighten up the type hinting to make it clear that parameter type declarations need to be valid type hints, not entirely arbitrary objects.

The rest of the comments are largely just a first pass at exploring the implications of that design clarification (I haven't tested them, or even type checked them, but they're at least a step in the desired direction)

One potential simplification is that once the defaults are being correctly populated, msgspec should take care of populating the generated JSON schema appropriately.

[ncoghlan]

Thanks for the update!

There are a few minor cleanups still needed (details inline), but I'll go ahead and make those myself before merging.

[baonudesifeizhai]

Thanks for the update!

There are a few minor cleanups still needed (details inline), but I'll go ahead and make those myself before merging.

i see some test fail , i will figure out

[ncoghlan]

Oh, that's annoying (Python 3.10):

TypeError: cannot inherit from both a TypedDict type and a non-TypedDict base class

It's due to python/cpython#89026 (the limitation was resolved in Python 3.11).

I'll just put a version guard on the ToolParameterDefDict definition, and use Any instead of the TypeVar on 3.10

[ncoghlan]

Thank you for the PR! This will be released as part of lmstudio-python 1.5.0.