# Overview The Cillers platform makes it super easy for developers to add functionality in ways that are aligned with Cillers' opinionated services, structure and tooling. But, Cillers is also super flexible and enables developers to add pretty much any functionality in any way they like, but they will then have less "for free". This section on how to build your system on Cillers is therefore structured in two main parts: * [Cillers Core](/building-your-system/cillers-core.md): How to add functionality using Cillers' opinionated services, structure and tooling. * [Cillers Flex](/building-your-system/cillers-flex.md): How to add functionality that is outside of the current scope of Cillers Core. --- # 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://docs.bluetext.dev/building-your-system/overview.md?ask= ``` 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.