MCP Academy · Lesson

Model Inputs with Pydantic

Define a typed shape for a tool's arguments.

A Model Per Input

To shape a tool's arguments, you write a Pydantic model: a small class where each attribute is one typed field of the input.

from pydantic import BaseModel

class SearchInput(BaseModel):
    query: str
    limit: int

Every input model inherits from BaseModel, which gives it parsing, validation, and JSON schema generation for free.