The Language Server Protocol (LSP) is a specification that standardizes how editors and IDEs communicate with language-smart backends over JSON-RPC. It defines capabilities such as completion, hover information, signature help, go-to definition, find references, diagnostics, code actions, formatting, rename, semantic tokens, and more. By decoupling tooling from individual editors, a single language server can power multiple clients, dramatically reducing duplicated effort across ecosystems. The protocol negotiates capabilities at startup so clients and servers can evolve independently while maintaining compatibility. Extensions and proposals cover advanced scenarios—like call hierarchies, inlay hints, notebooks, and workspace symbols—allowing incremental adoption as needs grow. ...