First Check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question 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

Exhibit 1

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/")
async def root(
    q: Annotated[str, Query(title="Query title", description="Query description")],
):
    return {"message": "Hello World"}

Exhibit 2

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/")
async def root(
    q: Annotated[
        str,
        Query(
            title="Query title",
            description="Query description",
            json_schema_extra={"description": None},
        ),
    ],
):
    return {"message": "Hello World"}

Description

Generated OpenAPI part for Query for Exhibit 1:

{
  "name": "q",
  "in": "query",
  "required": true,
  "schema": {
    "type": "string",
    "title": "Query title",
    "description": "Query description"
  },
  "description": "Query description"
}

As you see, description is pasted twice: into the description of the query and the description of its schema. Note that title doesn't behave like that. Moreover, if you run Exhibit 2, you get

{
  "name": "q",
  "in": "query",
  "required": true,
  "schema": {
    "type": "string",
    "title": "Query title"
  },
  "description": "Query description"
}

i.e. removing description with the help of json_schema_extra removes its from the schema but keeps it for the query.

That seems to be unintuitive and probably incorrect behaviour.

Operating System

macOS

Operating System Details

No response

FastAPI Version

0.115.11

Pydantic Version

2.10.6

Python Version

3.11.11

Additional Context

No response