```

This will validate the data, show a clear error when the data is not valid, and document the parameter in the OpenAPI schema *path operation*.

### `Query` as the default value or in `Annotated` { #query-as-the-default-value-or-in-annotated }

Keep in mind that when using `Query` inside of `Annotated` you cannot use the `default` parameter for `Query`.

    default void setSearchLog(final boolean value) {
        setSystemPropertyAsBoolean(Constants.SEARCH_LOG_PROPERTY, value);
    }

    default boolean isSearchLog() {
        return getSystemPropertyAsBoolean(Constants.SEARCH_LOG_PROPERTY, true);
    }

    default void setUserInfo(final boolean value) {
        setSystemPropertyAsBoolean(Constants.USER_INFO_PROPERTY, value);
    }

    default boolean isUserInfo() {

    assert '"dom_id": "#swagger-ui"' in response.text, (
        "default configs should be preserved"
    )
    assert "presets: [" in response.text, "default configs should be preserved"
    assert "SwaggerUIBundle.presets.apis," in response.text, (
        "default configs should be preserved"
    )
    assert "SwaggerUIBundle.SwaggerUIStandalonePreset" in response.text, (
        "default configs should be preserved"
    )

        include_in_schema: bool = True,
        json_schema_extra: Union[dict[str, Any], None] = None,
        **extra: Any,
    ):
        assert default is ..., "Path parameters cannot have a default value"
        self.in_ = self.in_
        super().__init__(
            default=default,
            default_factory=default_factory,
            annotation=annotation,
            alias=alias,
            alias_priority=alias_priority,

named `/godebug/non-default-behavior/<name>:events`
that counts the number of times a particular program's
behavior has changed based on a non-default value
for that setting.
For example, when `GODEBUG=http2client=0` is set,
`/godebug/non-default-behavior/http2client:events`
counts the number of HTTP transports that the program
has configured without HTTP/2 support.

## Default GODEBUG Values {#default}

            Doc(
                """
                The default response class to be used.

                Read more in the
                [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/#default-response-class).
                """
            ),
        ] = Default(JSONResponse),
        responses: Annotated[

* Data validation
* Automatic documentation

## Defaults { #defaults }

As query parameters are not a fixed part of a path, they can be optional and can have default values.

In the example above they have default values of `skip=0` and `limit=10`.

So, going to the URL:

```
http://127.0.0.1:8000/items/
```

Your response model could have default values, like:

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (or `str | None = None` in Python 3.10) has a default of `None`.
* `tax: float = 10.5` has a default of `10.5`.
* `tags: List[str] = []` has a default of an empty list: `[]`.

     * The default value is {@code "main"}.
     *
     * @see ProjectScope#MAIN
     */
    default ProjectScope scope() {
        return ProjectScope.MAIN;
    }

    /**
     * {@return the language of the source files}
     * The default value is {@code "java"}.
     *
     * @see Language#JAVA_FAMILY
     */
    default Language language() {

Python will complain if you put a value with a "default" before a value that doesn't have a "default".

But you can re-order them, and have the value without a default (the query parameter `q`) first.

It doesn't matter for **FastAPI**. It will detect the parameters by their names, types and default declarations (`Query`, `Path`, etc), it doesn't care about the order.