Markdownkit Language Server

A Language Server Protocol (LSP) implementation for markdown files using remark.

Features

• Linting - remark-lint diagnostics on open/save (optionally as you type)
• Document formatting - Format on save or demand
• Code actions - Quick fixes for common issues
• MDD validation - Real-time frontmatter, directive, and document-type diagnostics for .mdd files
• MDD preview - Generate professional HTML from .mdd content
• Custom commands - Autoformat, draft transform, MDD preview, MDD validate
• Configuration - Uses .remarkrc files
• Multi-format support - .md, .mdx, .mdc, .mdd

Installation

npm install -g @markdownkit/lsp

Usage

With stdio (recommended for editors)

markdownkit-lsp --stdio

Programmatic usage

import { createMarkdownkitServer } from "@markdownkit/lsp";

createMarkdownkitServer();

MDD preview

import { generateMddHtml } from "@markdownkit/lsp/mdd-preview";

const html = await generateMddHtml(mddContent);

Custom LSP Commands

| Command | Arguments | Description | | -------------------------- | ------------------------------------------------------ | ----------------------------------------------------------------- | | markdownkit.formatText | [text, { filePath, cwd, semanticBreaks, wrapWidth }] | Format markdown text with the shared markdownkit formatter | | markdownkit.autoformat | [text, options] | Transform plain text → markdown | | markdownkit.draft | [text, options] | NLP-enhanced rough text transformation | | markdownkit.polish | [text, options] | Typography-only polish of existing markdown (nuclear-mode step 1) | | markdownkit.mddPreview | [content, { filePath }] | Generate HTML preview from MDD content | | markdownkit.mddValidate | [content, { strict }] | Validate MDD document, return result object | | markdownkit.validateText | [text, { filePath }] | Diagnostics for arbitrary text using the file's rule set | | markdownkit.lintDocument | [uri] | Re-validate an open document now; returns { errors, warnings } | | markdownkit.oxlintFix | [filePath] | Run oxlint-mdx --fix on a saved file |

Diagnostics

• .md / .mdx / .mdc: remark-lint via the project's .remarkrc* (or the markdownkit presets when none is found), plus oxlint-mdx for embedded code (on save, when @markdownkit/oxlint-mdx is installed in the project or alongside the server).
• .mdd: the canonical MDD validator (@markdownkit/remark-mdd/validator), exactly as markdownkit lint and mdd-validate report, plus remark-lint through markdownkit's MDD-safe processor (no MDX/MDC parsing; [Placeholder] text is not reported as an undefined reference).

Diagnostics are published on open and on save; set markdownkit.lint.onType to also lint while typing (markdownkit.lint.delay debounces it).

Editor Integration

VS Code

Install the Markdownkit extension which uses this server.

Neovim

require('lspconfig').markdownkit_lsp.setup {
  cmd = { 'markdownkit-lsp', '--stdio' },
  filetypes = { 'markdown', 'mdx', 'mdc', 'mdd' },
}

Emacs (lsp-mode)

(lsp-register-client
  (make-lsp-client
    :new-connection (lsp-stdio-connection '("markdownkit-lsp" "--stdio"))
    :major-modes '(markdown-mode)
    :server-id 'markdownkit-lsp))

Configuration

Create a .remarkrc.js in your project:

export default {
  settings: {
    bullet: "-",
    emphasis: "_",
    strong: "*",
  },
  plugins: [
    "remark-gfm",
    "remark-frontmatter",
    "remark-preset-lint-recommended",
  ],
};

License

MIT