FastMCP

""" FastMCP Complex inputs Example Demonstrates validation via pydantic with complex models. """ from typing import Annotated from pydantic import BaseModel, Field from mcp.server.fastmcp import FastMCP mcp = FastMCP("Shrimp Tank") class ShrimpTank(BaseModel): class Shrimp(BaseModel): name: Annotated[str, Field(max_length=10)] shrimp: list[Shrimp] @mcp.tool() def name_shrimp( tank: ShrimpTank, # You can use pydantic Field in function signatures for validation. extra_names: Annotated[list[str], Field(max_length=10)], ) -> list[str]: """List all shrimp names in the tank""" return [shrimp.name for shrimp in tank.shrimp] + extra_names