First Check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to FastAPI but to Pydantic.
• I already checked if it is not related to FastAPI but to Swagger UI.
• I already checked if it is not related to FastAPI but to ReDoc.

Commit to Help

• I commit to help with one of those options 👆

Example Code

from fastapi import FastAPI

from pydantic import BaseModel

app = FastAPI()


class TypicalResponse(BaseModel):
    msg: str
    data: int


@app.get("/add/{x}/{y}")
async def add(x: int, y: int) -> TypicalResponse:
    return TypicalResponse(msg="Done!", data=x + y)

Description

Open the automatic doc on this handler
See no output schema defined
I would like to use typing "-> Type" for annotate response model.
This is good for simple handlers.

Wanted Solution

I would like to autodoc parse this typing same as "response_model=TypicalResponse"

Wanted Code

from fastapi import FastAPI

from pydantic import BaseModel

app = FastAPI()

# Same
class TypicalResponse(BaseModel):
    msg: str
    data: int


@app.get("/add/{x}/{y}")
async def add(x: int, y: int) -> TypicalResponse:
    return TypicalResponse(msg="Done!", data=x + y)

Alternatives

I use kwarg "response_model" as single alternative
But typing already defines the output model, necessary duplicate as result.

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.79.0

Python Version

Python 3.9.0

Additional Context

Without patch:

With patch:

I think second is better by avoid information duplication

Meanwhile, solution is quite simple.
One of the ways to implement (don't judge too much, that's first idea):

1. Open APIRouter class
2. Modify self.add_api_route by adding
   

May be dirty, so welcome to search another ways.