* They don't specify whether a specific proxy server should be used or how to authenticate with that proxy server.

You only give `Depends` a single parameter.

This parameter must be something like a function.

You **don't call it** directly (don't add the parenthesis at the end), you just pass it as a parameter to `Depends()`.

And that function takes parameters in the same way that *path operation functions* do.

/// tip

And the proxy would be **"stripping"** the **path prefix** on the fly before transmitting the request to the app server (probably Uvicorn via FastAPI CLI), keeping your application convinced that it is being served at `/app`, so that you don't have to update all your code to include the prefix `/api/v1`.

Up to here, everything would work as normally.

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But if you use the same model as an output, like here:

{* ../../docs_src/separate_openapi_schemas/tutorial001_py310.py hl[19] *}

...then because `description` has a default value, if you **don't return anything** for that field, it will still have that **default value**.

### Model for Output Response Data { #model-for-output-response-data }

///

## Response Status Code { #response-status-code }

You can define the (HTTP) `status_code` to be used in the response of your *path operation*.

You can pass directly the `int` code, like `404`.

But if you don't remember what each number code is for, you can use the shortcut constants in `status`:

{* ../../docs_src/path_operation_configuration/tutorial001_py310.py hl[1,15] *}

            "ETag",
            "v1",
            "Vary",
            "Accept-Charset",
            "Donut",
            "a",
          ),
        body = "A",
      ),
    )
    server.enqueue(
      MockResponse
        .Builder()
        .clearHeaders()
        .addHeader("Donut: b")
        .code(HttpURLConnection.HTTP_NOT_MODIFIED)
        .build(),
    )
    client =

it would **work as expected**. If there's a **required** parameter (without a default value), your **editor** will let you know with an error, **Python** will also complain if you run it without passing the required parameter.

When you don't use `Annotated` and instead use the **(old) default value style**, if you call that function without FastAPI in **other places**, you have to **remember** to pass the arguments to the function for it to work correctly, otherwise the values will be...

* If the PR updates one of the internal dependencies, for example it's modifying `requirements.txt` files, or GitHub Action versions, if the tests are passing, the release notes (shown in a summary in the PR) don't show any obvious potential breaking change, you can merge it. 😎

# OpenAPI

There are several utilities to handle OpenAPI.