> For the complete documentation index, see [llms.txt](https://php-fhir-tools.ardenexal.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://php-fhir-tools.ardenexal.net/getting-started/packages.md).

# Choosing the Right Package

This is a library monorepo. Each component is published as a standalone Composer package.

| Package                          | Use it when you need to…                                                   |
| -------------------------------- | -------------------------------------------------------------------------- |
| `ardenexal/fhir-bundle`          | Integrate with a Symfony application (wires everything + console commands) |
| `ardenexal/fhir-code-generation` | Generate PHP classes from FHIR definitions / Implementation Guides         |
| `ardenexal/fhir-serialization`   | Read/write FHIR JSON or XML                                                |
| `ardenexal/fhir-validation`      | Validate resources against base and profile constraints                    |
| `ardenexal/fhir-path`            | Evaluate FHIRPath 2.0 expressions                                          |
| `ardenexal/fhir-models`          | Use the pre-generated R4 / R4B / R5 model classes                          |
| `ardenexal/fhir-metadata`        | Shared FHIR attributes and interfaces (a dependency of the others)         |

{% hint style="info" %}
`ardenexal/fhir-serialization` needs model classes to read and write — it already depends on `ardenexal/fhir-models`, so they come together. Generate your own classes instead with `ardenexal/fhir-code-generation` when you need versions or Implementation Guides that the pre-generated models do not cover.
{% endhint %}

{% hint style="info" %}
Validation lives in its own package, `ardenexal/fhir-validation`, not in `ardenexal/fhir-serialization`. The `ardenexal/fhir-bundle` brings in serialization, validation, FHIRPath, code generation, and metadata together.
{% endhint %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## 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://php-fhir-tools.ardenexal.net/getting-started/packages.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.