Tree-sitter can be used in conjunction with its [tree query language](https://tree-sitter.github.io/tree-sitter/using-parsers#pattern-matching-with-queries) as a part of code navigation systems. An example of such a system can be seen in the `tree-sitter tag` command, which emits a textual dump of the interesting syntactic nodes in its file argument. This document exists to provide guidelines on the design and use of tree-sitter concepts to implement such systems.
*Tagging* is the act of identifying the entities that can be named in a program. We use Tree-sitter queries to find those entities. Having found them, you use a syntax capture to label the entity and its name.
The essence of a given tag lies in two pieces of data: the _kind_ of entity that is matched (usually a definition or a reference) and the _role_ of that entity, which describes how the entity is used (i.e. whether it's a class definition, function call, variable reference, and so on). Our convention is to use a syntax capture following the `@role.kind` capture name format, and another inner capture, always called `@name`, that pulls out the name of a given identifier.
The below table describes a standard vocabulary for kinds and roles during the tagging process. User applications may extend (or only recognize a subset of) these capture names, but it is desirable to standardize on the names below when supported by a given system or language. Language communities that write tagging rules using these names can work out-of-the-box with a steadily increasing set of analysis tools
