### Check the docs { #check-the-docs }

Now, if you check the docs, they will show all the additional metadata:

<img src="/img/tutorial/metadata/image02.png">

### Order of tags { #order-of-tags }

The order of each tag metadata dictionary also defines the order shown in the docs UI.

For example, even though `users` would go after `items` in alphabetical order, it is shown before them, because we added their metadata as the first dictionary in the list.

* `title`: The OpenAPI title, shown in the docs.
* `version`: The version of your API, e.g. `2.5.0`.
* `openapi_version`: The version of the OpenAPI specification used. By default, the latest: `3.1.0`.
* `summary`: A short summary of the API.
* `description`: The description of your API, this can include markdown and will be shown in the docs.

To add a summary and description to your *path operations*, and show them in the docs UI, read the docs for [Tutorial - Path Operation Configurations - Summary and Description](../tutorial/path-operation-configuration.md#summary-and-description){.internal-link target=_blank}.

## Documentation Response description - OpenAPI { #documentation-response-description-openapi }

{* ../../docs_src/additional_responses/tutorial003.py hl[20:31] *}

It will all be combined and included in your OpenAPI, and shown in the API docs:

<img src="/img/tutorial/additional-responses/image01.png">

## Combine predefined responses and custom ones { #combine-predefined-responses-and-custom-ones }

<img src="/img/tutorial/generate-clients/image01.png">

You can see those schemas because they were declared with the models in the app.

That information is available in the app's **OpenAPI schema**, and then shown in the API docs.

That same information from the models that is included in OpenAPI is what can be used to **generate the client code**.

### Hey API { #hey-api }

## Automatic docs { #automatic-docs }

The JSON Schemas of your models will be part of your OpenAPI generated schema, and will be shown in the interactive API docs:

<img src="/img/tutorial/body/image01.png">

And will also be used in the API docs inside each *path operation* that needs them:

<img src="/img/tutorial/body/image02.png">

Each specific example `dict` in the `examples` can contain:

* `summary`: Short description for the example.
* `description`: A long description that can contain Markdown text.
* `value`: This is the actual example shown, e.g. a `dict`.
* `externalValue`: alternative to `value`, a URL pointing to the example. Although this might not be supported by as many tools as `value`.

You can use it like this:

///

FastAPI will now:

* **Validate** the data making sure that the max length is 50 characters
* Show a **clear error** for the client when the data is not valid
* **Document** the parameter in the OpenAPI schema *path operation* (so it will show up in the **automatic docs UI**)

## Alternative (old): `Query` as the default value { #alternative-old-query-as-the-default-value }

All these dependencies, while declaring their requirements, also add parameters, validations, etc. to your *path operations*.

<font color="#A6E22E">INFO</font>:     Application startup complete.
```

</div>

////

The only new option here is `--workers` telling Uvicorn to start 4 worker processes.

You can also see that it shows the **PID** of each process, `27365` for the parent process (this is the **process manager**) and one for each worker process: `27368`, `27369`, `27370`, and `27367`.

## Deployment Concepts { #deployment-concepts }