Inconsistent Field Naming Between `outputSchema` and `model_dump`

[akolotov]

If the model to return by a tool is defined like:

class Foo(BaseModel):
    field_first: str | None = Field(
        default=None, alias="first", description="The first field."
    )
    field_second: str | None = Field(
        default=None, alias="second", description="The second field."
    )

In outputSchema of tools/list they will be displayed as "first" and "second".

At the same time model_dump in

python-sdk/src/mcp/server/fastmcp/utilities/func_metadata.py

Line 114 in 6f43d1f

structured_content = validated.model_dump(mode="json")

will produce the dump with "field_first" and "field_second".

To keep the schema and the tool response consistent, consider adding by_alias=True to the call of model_dump.