> For the complete documentation index, see [llms.txt](https://help.connected.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.connected.illumina.com/run-set-up/overview/sample-sheet-structure/section-requirements.md).

# Section Requirements

<table><thead><tr><th width="224">Section Type</th><th>Requirements</th></tr></thead><tbody><tr><td>All sections</td><td><ul><li>Data items cannot contain commas.</li><li>Supported line endings are <code>\n, \r\n,</code> and .</li><li>Required characters are all ASCII characters except for <code>*</code> and the control characters <code>CR</code> and <code>LF</code>.</li></ul></td></tr><tr><td>Standalone</td><td><ul><li>Only key-value pairs are supported.</li><li>Each key must have exactly one value.</li><li>The same key cannot be specified more than one time in a single standalone section.</li><li>Opening and closing brackets are both required, and must be the first and last character in the section header line (other than whitespace and commas).</li><li>A standalone section cannot be empty.</li><li>Data in standalone sections must not contain brackets.</li></ul></td></tr><tr><td>Header</td><td><ul><li>There can only be one data item in a section header line.</li><li>Section headers are required to start with an opening square bracket, and end with a closing square bracket</li><li>Opening and closing brackets are both required, and must be the first and last character in the section header line (other than whitespace and commas)</li></ul></td></tr><tr><td>Application</td><td><ul><li>The application name cannot include <code>Settings</code> or <code>Data</code>.</li><li>The application name cannot be empty.</li><li>The application name cannot include -.</li><li>Each application can have a maximum of one <code>Settings</code> section and one <code>Data</code> section.</li></ul></td></tr><tr><td>Application Settings</td><td><ul><li>Settings sections can support only key-value pairs.</li><li>Each key can have only one value.</li><li>The application name cannot include -.</li><li>Applications sections cannot be empty. At least one key-value pair must be specified.</li><li>Keys and values cannot contain <code>[</code> or <code>]</code>.</li><li><mark style="color:red;">Note: The Settings section is applied globally to all samples.</mark></li></ul></td></tr><tr><td>Application Data</td><td><ul><li>For each line that follows the column header line in the application data section, the number of empty plus non-empty data items cannot be less than the number of column headers.</li><li>For each line that follows the column header line in the Application Data section, the number of non-empty values cannot be greater than the number of column headers.</li><li>Column headers must all be unique.</li><li>Each application data section must contain a column header called <code>Sample_ID</code>.</li><li>Column headers and values cannot contain <code>[</code> or <code>]</code>.</li><li><mark style="color:red;">Note: The Data section is uniquely applied to each sample.</mark></li></ul></td></tr></tbody></table>


---

# 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, and the optional `goal` query parameter:

```
GET https://help.connected.illumina.com/run-set-up/overview/sample-sheet-structure/section-requirements.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

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.