fastmcp.apps.form
FormInput — a Provider that collects structured input from the user.
Define a Pydantic model for the data you need, and FormInput
generates a form UI. The user fills it out, the submission is
validated, and an optional callback processes the result.
Requires fastmcp[apps] (prefab-ui).
Usage::
from pydantic import BaseModel
from fastmcp import FastMCP
from fastmcp.apps.form import FormInput
class ShippingAddress(BaseModel):
street: str
city: str
state: str
zip_code: str
mcp = FastMCP(“My Server”)
mcp.add_provider(FormInput(model=ShippingAddress))
Classes
FormInput
A Provider that collects structured input via a Pydantic model.
Define a model for the data you need, and FormInput generates
a form from it using Form.from_model(). Field types, labels,
descriptions, and validation are all derived from the model.
Optionally provide an on_submit callback to process the
validated data. The callback receives a model instance and returns
a string that goes back to the LLM. Without a callback, the
validated JSON is sent directly.
Example::
from pydantic import BaseModel
from fastmcp import FastMCP
from fastmcp.apps.form import FormInput
class Contact(BaseModel):
name: str
email: str
mcp = FastMCP(“My Server”)
mcp.add_provider(FormInput(model=Contact))
With a callback::
def save_contact(contact: Contact) -> str:
db.insert(contact.model_dump())
return f”Saved ”
mcp.add_provider(FormInput(model=Contact, on_submit=save_contact))