Summary

Optional parameters (Optional[T] types or params with default values) were unconditionally added to the required list in the tool JSON schema. This caused MCP clients/LLMs to treat every parameter as mandatory, prompting users for values that should be optional.

Changes

• Check for Union[X, None] (i.e. Optional[T]) type hints before adding to required
• Check for parameters with default values via inspect.signature
• Added tests: test_tool_decorator_required_vs_optional_params and test_tool_decorator_all_required_params
• Updated existing test_tool_decorator_optional_type_hints to assert required == []
• Added a demo script showing correct schema generation

Before (broken)

@mcp.tool()
def search(query: str, limit: Optional[int] = 10):
    ...
# required: ['query', 'limit']  <-- limit should NOT be required

After (fixed)

@mcp.tool()
def search(query: str, limit: Optional[int] = 10):
    ...
# required: ['query']  <-- correct

Fixes #1119

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