# Dynamic tags The tag types discussed thus far must be set up in the opening definitions section of your protocol, before the execution of the first `STEP`, and once they are defined, what they refer to cannot be changed. **Dynamic tags** are tags that can be defined later in your protocol and used to refer to the result of a selection statement when a tag is chosen from a group. They don't have a fixed identity as "meaning" any other particular tag; rather, they work as a placeholder tag that can still be reassigned to a new item later on in the execution of the protocol. Dynamic tags are explained further in the section on [randomization and selection from groups](/bittsy/creating-protocols/selection-and-randomization.md). But they are another type of tag that, once defined, work in the same way as the tags discussed thus far. They can reference a particular stimulus file or they can reference a group, and they can be used in selection statements or action statements in the same way as static tags. --- # 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://ldevumd.gitbook.io/bittsy/creating-protocols/tags/dynamic-tags.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.