Language Server Protocol

The Language Server Protocol is a common way for a program that writes code (the editor) and a program that actually understands that code's grammar (the language server) to talk to each other. It's a bit like having one interpreter that people from many countries can talk to using the same agreed-upon method, and communication works no matter what language they speak. The editor just has to ask the interpreter questions in a fixed format, and the language server handles figuring out whether the code is Python, Java, or JavaScript.

Before this existed, every editor maker had to build its own autocomplete and error-checking features separately for every programming language it wanted to support. With the Language Server Protocol, an editor only needs to support this one standard, and it can then connect to any language server that follows the same standard. The key idea is separating the editor from the language-understanding features, so the two can be mixed and matched freely.

In articles about Claude Code, you might see something like "you can even add Language Server Protocol (LSP) servers, background monitors, and themes." Here, the LSP server isn't a new feature Claude Code invented—it means Claude Code can bundle the existing standard communication protocol that code editors already use into its plugins for distribution.