Language Server
devenv lsp starts a bundled nixd language server pre-configured for your devenv.nix. It provides autocomplete, hover documentation, and go to definition in any editor that supports LSP.
Usage
The command assembles your devenv configuration, generates the appropriate nixd settings (nixpkgs expression and devenv options), and then replaces itself with the nixd process. Your editor communicates with it over stdio.
Editor setup
Most editors can be configured to use devenv lsp as the Nix language server. Point your editor's LSP client at devenv lsp as the server command.
If you need the generated nixd configuration for manual editor setup:
This prints the nixd JSON configuration and exits without starting the server.