Allow customizing property name and title for scalar elicitation types

[pamelafox]

Description

When using scalar types like bool or str as response_type in ctx.elicit(), FastMCP wraps them in an object schema with a hardcoded property name "value" and title "ScalarElicitationType":

{"requestedSchema":{"properties":{"value":{"title":"Value","type":"boolean"}},"required":["value"],"title":"ScalarElicitationType","type":"object"}}

Clients like VS Code render these as the field label ("Value") and object title ("ScalarElicitationType"), which looks generic and confusing to users. The MCP spec supports title and description on individual properties (spec reference).

Current workaround

Use a full Pydantic BaseModel to get control over field titles:

from pydantic import BaseModel, Field

class PurchaseConfirmation(BaseModel):
    confirm: bool = Field(title="Confirm purchase", description="Approve this transaction?")

response = await ctx.elicit(message="Buy 1x Baguette?", response_type=PurchaseConfirmation)

This works but is verbose for a simple confirmation.

Proposed enhancement

Allow passing title and/or description kwargs to ctx.elicit() when using scalar types, which would be applied to the wrapped property:

# Hypothetical API
response = await ctx.elicit(
    message="Buy 1x Baguette?",
    response_type=bool,
    title="Confirm purchase",
    description="Approve this transaction?",
)

Environment

• FastMCP 3.2.3

[jlowin]

Great enhancement. Adding as response_title and response_description just for clarity and to align with response_type