Language Server Protocol (LSP) is a standard that supports a code editor or an Integrated Development Environment (IDE) to achieve “code intelligence” such as auto-completion, go-to definition, syntax highlights, etc. After the wide adoption of LSP, editors and IDEs can utilize their LSP clients to serve coding intelligence without implementing their own for every programming language. Besides, programming language developers can build Language Servers to get predictable editor/IDE support for each programming language.
Also, Claude Code has supported LSPin December 2025.
Pyright and Pylance
Pyright is an open source Python Language Server developed by Microsoft. Since Microsoft also creates VSCode, we expect Pyright to provide other code editors with the same feature set. However, the full feature Python language server in VSCode is Pylance, which is kept proprietary by Microsoft.
BasedPyright
BasedPyrightis a fork of Pyright to incorporate more features that include Pylance-only ones. LSP clients of other IDEs, such as Neovim, Emacs, and PyCharm, can utilize it well. We should use and support it to maintain the vibrant choices of code editors and IDEs, rather than being locked into VSCode.