skill-language-server

Your skill library now has tooling.

▸ completion w/ descriptions on / and $
▸ "did you mean" on typos
▸ go to definition, find references
▸ F2 rename w/ editor undo — folder, frontmatter name:, and every reference update as one edit
▸ clickable links + semantic highlighting on resolved references

Why

Skills, CLAUDE.md/AGENTS.md, and agent files reference each other by name — a dependency graph with all the refactoring hazards of code and none of the tooling. Rename a skill by hand and stale references look like ordinary prose: nothing errors, the agent silently stops loading the skill.

Quiet by design — a false reference in prose costs more than a missed one:

• Fenced code blocks are never parsed; inline code spans are (that's how people write skill names in prose)
• /usr/bin, $PATH, docs/ — never references, never popups
• Near miss of a real skill (edit distance ≤ 2) → did you mean warning; other unresolved /name → info hint; unresolved $name → silent
• Built-in commands (/help, /compact, …) and your own .claude/commands/.codex/prompts are commands, not skills — never flagged

It's a language server, not a linter — pair with skill-lint or agnix for structural/security linting.

Install

Cursor / Antigravity / VSCodium · Zed · VS Code · Neovim · Helix · from source

Once installed: cursor on any /skill-name, hit F2, type a new name — folder, frontmatter, and every reference update as one undo step.

Cursor / Antigravity / VSCodium

Install the extension — or cmd-shift-x → search Agent Skills Language Server. Same for Windsurf and anything else pointed at Open VSX. The extension bundles the server; nothing else to install.

Zed

Install the extension — or cmd-shift-x → search Skill Language Server. It fetches the server itself; nothing else to install.

From a clone instead: command palette → zed: install dev extension → select ext/zed/. After server updates, editor: restart language server.

VS Code

Install the extension — or cmd-shift-x → search Agent Skills Language Server. The extension bundles the server; nothing else to install.

Neovim (0.11+)

1. Install the server:

   npm install -g skill-language-server

2. Create ~/.config/nvim/lsp/skill-language-server.lua:

   return {
     cmd = { "skill-language-server", "--stdio" },
     filetypes = { "markdown" },
     root_markers = { ".claude", ".git" },
   }

3. Add vim.lsp.enable("skill-language-server") to init.lua.

(Or from a clone, skipping steps 1–2: { dir = "/path/to/skill-language-server/ext/nvim" } in lazy.nvim.)

Helix

1. Install the server:

   npm install -g skill-language-server

2. Add to languages.toml:

   [language-server.skill-language-server]
   command = "skill-language-server"
   args = ["--stdio"]
   
   [[language]]
   name = "markdown"
   language-servers = ["skill-language-server"]  # add e.g. "marksman" here if you use it

From source

git clone https://github.com/CyrusNuevoDia/skill-language-server
cd skill-language-server
mise trust && mise install   # bun, just (rust only for the Zed wasm)
bun install
just bin                     # → ~/.local/bin/skill-language-server (Neovim, Helix, Zed)

For the VS Code–family editors, build and sideload the extension instead:

just build-vscode
code --install-extension dist/skill-language-server.vsix   # or cursor / codium / …

How it scans

The server's world is the folder your editor opened — it never reads outside it. A rename touches exactly the tree you have open, never another checkout or your home directory. Open ~/.claude itself as a workspace to refactor your global library.

• Skills = any **/skills/<name>/SKILL.md. Folder name is canonical; a disagreeing frontmatter name: is an error, not an alias
• References are scanned in .md files under .claude/, .agents/, .codex/, or skills/, plus every CLAUDE.md/AGENTS.md. Markdown elsewhere is never touched
• Live index where the editor supports LSP file watching; open buffers beat disk. Without watching, the index catches up on file open or restart
• .skillignore (gitignore syntax, workspace root) excludes paths from everything — ! negation re-includes, with git's usual rule that you can't re-include inside an excluded directory (dir/* + !dir/keep/ works; dir/ + !dir/keep/ doesn't)
• Multi-root workspaces: only the first folder is indexed

Cross-workspace renames are a deliberate two-step: rename where the skill lives, then open the other workspace — stale references surface as hints/warnings there. Blind spots: $ stragglers stay silent, and an old name that doubles as a built-in command reads as the built-in.

Client compatibility

Checked against client source as of 2026-07: VS Code, Zed, Helix, and Neovim all apply the folder RenameFile.

• Neovim never sends willRenameFiles — explorer-drag renames don't rewrite references there; rename from a token or the frontmatter instead
• File watching: VS Code and Zed yes; Neovim yes except off by default on Linux; Helix only sees its own edits — reopen the file or restart the server after external changes

Development

just fmt     # ultracite fix --unsafe
just check   # tsc (server + VS Code extension) + ultracite lint + bun test
just build   # everything into dist/ — binary, .vsix, Zed wasm (wasm needs rust)

The test suite is the contract: tests/helpers/harness.ts boots the real server over in-memory streams; tests/corpus.ts is the ground-truth reference set. Done = just check green.

Three layers in src/: parse.ts (token grammar), workspace.ts (index), server.ts (LSP wiring). Editor shims in ext/{vscode,zed,nvim}.

Releases via changesets: bun changeset with your change, merge to main, CI publishes.

License

MIT