# Naming rules of a Variable

Users can create variables and must give them names to identify them while working in Actions. The naming rules for a variable are: 

* The variable's name must begin with a letter (A-Z or a-z). Digits (0-9) and \_ (underscore) are allowed after the first letter.
* The name cannot contain whitespaces or special characters such as !, #, %, . (dot), etc. 
* The variable name must be unique in the same scope. 
* Names are case insensitive, so the variables “mycustomer” and “MyCustomer” are identical. 
* Reserved words cannot be used as names for variables (see the list below). 
* The Langstack application reserved keywords for variables are as follows:

<table><thead><tr><th></th><th></th><th></th><th></th><th data-hidden></th></tr></thead><tbody><tr><td>abstract</td><td>datetime</td><td>list</td><td>return</td><td></td></tr><tr><td>add</td><td>decimal</td><td>long</td><td>sbyte</td><td></td></tr><tr><td>bool</td><td>default</td><td>namespace</td><td>set</td><td></td></tr><tr><td>boolean</td><td>delegate</td><td>new</td><td>short</td><td></td></tr><tr><td>byte</td><td>double</td><td>null</td><td>string</td><td></td></tr><tr><td>case</td><td>enum</td><td>numeric</td><td>this</td><td></td></tr><tr><td>catch</td><td>FALSE</td><td>object</td><td>TRUE</td><td></td></tr><tr><td>char</td><td>float</td><td>operator</td><td>uint</td><td></td></tr><tr><td>class</td><td>function</td><td>package</td><td>ulong</td><td></td></tr><tr><td>const</td><td>int</td><td>variable</td><td>void</td><td></td></tr><tr><td>date</td><td>json</td><td>public</td><td></td><td></td></tr></tbody></table>


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# 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.langstack.com/welcome/get-started/learn-langstack/basics-and-essentials/what-is-a-variable/naming-rules-of-a-variable.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.