# Structuring your API reference

GitBook does more than just render your OpenAPI spec. It lets you customize your API reference for better clarity, navigation, and branding.

### Split operations across multiple pages

To keep your documentation organized, GitBook can split your API operations into separate pages. Each page is generated from a tag in your OpenAPI spec. To group operations into a page, assign the same tag to each operation:

<pre class="language-yaml" data-title="openapi.yaml"><code class="lang-yaml">paths:
  /pet:
    put:
<strong>      tags:
</strong><strong>        - pet
</strong>      summary: Update an existing pet.
      description: Update an existing pet by Id.
      operationId: updatePet
</code></pre>

### Reorder pages in your table of contents

The order of pages in GitBook matches the order of tags in your OpenAPI tags array:

<pre class="language-yaml" data-title="openapi.yaml"><code class="lang-yaml">tags:
<strong>  - name: pet
</strong><strong>  - name: store
</strong><strong>  - name: user
</strong></code></pre>

### Nest pages into groups

To build multi-level navigation, use `x-parent` (or `parent`) in tags to define hierarchy:

<pre class="language-yaml" data-title="openapi.yaml"><code class="lang-yaml">tags:
  - name: everything
  - name: pet
<strong>    x-parent: everything
</strong>  - name: store
<strong>    x-parent: everything
</strong></code></pre>

The above example will create a table of contents that looks like:

```
Everything
├── Pet
└── Store
```

If a page has no description, GitBook will automatically show a card-based layout for its sub-pages.

### Customize page titles, icons, and descriptions

You can enhance pages with titles, icons, and descriptions using custom extensions in the tags section. All [Font Awesome icons](https://fontawesome.com/search) are supported via `x-page-icon`.

{% code title="openapi.yaml" %}

```yaml
tags:
  - name: pet
    # Page title displayed in table of contents and page
    x-page-title: Pet
    # Icon shown in table of contents and next to page title
    x-page-icon: dog
    # Description shown just above the title
    x-page-description: Pets are amazing!
    # Content of the page
    description: Everything about your Pets
```

{% endcode %}

### Build rich descriptions with GitBook Blocks

Tag description fields support GitBook markdown, including [advanced blocks](/docs/creating-content/blocks.md) like tabs:

{% code title="openapi.yaml" %}

```yaml
---
tags:
  - name: pet
    description: |
      Here is the detail of pets.

      {% tabs %}
      {% tab title="Dog" %}
      Here are the dogs
      {% endtab %}

      {% tab title="Cat" %}
      Here are the cats
      {% endtab %}

      {% tab title="Rabbit" %}
      Here are the rabbits
      {% endtab %}
      {% endtabs %}
```

{% endcode %}

### Highlight schemas

You can highlight a schema in a GitBook description by using GitBook markdown. Here is an example that highlights the “Pet” schema from the “petstore” specification:

{% code title="openapi.yaml" %}

```yaml
---
tags:
  - name: pet
      description: |
          {% openapi-schemas spec="petstore" schemas="Pet" grouped="false" %}
              The Pet object
          {% endopenapi-schemas %}
```

{% endcode %}

### Document a webhook endpoint

GitBook also supports documenting webhook endpoints when using OpenAPI 3.1.

You can define your webhooks directly in your OpenAPI file using the `webhooks` field, which works similarly to `paths` for regular API endpoints:

{% code title="openapi.yaml" %}

```yaml
---
openapi: 3.1.0 # Webhooks are available starting from OpenAPI 3.1

webhooks:
  newPet:
    post:
      summary: New pet event
      description: Information about a new pet in the system
      requestBody:
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/Pet"
      responses:
        "200":
          description: Return a 200 status to indicate that the data was received successfully
```

{% endcode %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://gitbook.com/docs/api-references/guides/structuring-your-api-reference.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.