CTags Language Server

A Language Server Protocol (LSP) implementation using universal-ctags as backend, supporting 100+ languages.

This won't replace your dedicated language server, and it doesn't try to. The goal is to have a "better than nothing" language server that's trivial to setup for any language.

What it does

On startup, ctags-lsp runs universal-ctags to index your workspace and keeps that index in memory to provide code completion, go-to-definition, and document/workspace symbols.

It never creates or updates tagfiles.

Installation

brew will automatically install dependencies for you.

# install with brew
brew install ctags-lsp

When installing with mise or go, you must install universal-ctags yourself (ctags installation).

# install with mise
mise use -g github:netmute/ctags-lsp

# install with go
go install github.com/netmute/ctags-lsp@latest

Use with your editor

Any editor with a built-in LSP client should work. Working examples are below.

Neovim

vim.lsp.config("ctags_lsp", {
	cmd = { "ctags-lsp" },
	filetypes = { "ruby" }, -- Change this to the language(s) nvim should attach the LSP to
})
vim.lsp.enable("ctags_lsp")

Helix

Add this to ~/.config/helix/languages.toml:

[language-server.ctags-lsp]
command = "ctags-lsp"

[[language]]
name = "toml"  # Change this to the language helix should attach the LSP to
language-servers = [ "ctags-lsp" ]

Advanced

Speeding up startup

Most projects are completely indexed in less than 1s. If startup is slow for your workspace:

• Limit which languages are being indexed with --languages. The option is passed through to ctags unchanged; for available options see the universal-ctags manual on the topic.
• Leverage an existing tagfile, so ctags-lsp doesn’t have to run ctags on startup, with --tagfile.

Tagfiles

You can use an existing tagfile with --tagfile=<path>. When set, the server parses the tagfile and skips the workspace scan. This is only intended as a fallback option to possibly improve performance, and should not be used otherwise.

ctags-lsp will never write or update tagfiles.

For obvious reasons, --languages has no effect when using a tagfile.

CLI options

> ctags-lsp --help

CTags Language Server
Provides LSP functionality based on ctags.

Usage:
  ctags-lsp [options]

Options:
  --help               Show this help message
  --version            Show version information
  --ctags-bin <name>   Use custom ctags binary name (default: "ctags")
  --tagfile <path> Use tagfile instead of scanning
  --languages <value>  Pass through language filter list to ctags