Getting Started

Installation

pnpm

pnpm add -D @crackdown/core @crackdown/cli

npm

npm install --save-dev @crackdown/core @crackdown/cli

60-second usage

1. Lint a file

   npx crackdown lint README.md

   Output:

   README.md
     12:1  warn  crackdown:no-trailing-spaces  MD009: Trailing spaces found

2. Auto-fix mechanical issues

   npx crackdown lint --fix README.md

3. Add a crackdown.config.ts for custom rules

   crackdown.config.ts

   import { md009Rule, md009Fixer, md010Rule, md010Fixer } from '@crackdown/core'
   import {
     md040Rule, md041Rule, md047Rule, md047Fixer,
   } from '@crackdown/compat-markdownlint'
   import { remarkLintMermaid } from '@crackdown/plugin-mermaid'
   import type { MarkyConfig } from '@crackdown/core'
   
   const config: MarkyConfig = {
     plugins: [
       md009Rule,        // no trailing spaces
       md010Rule,        // no hard tabs
       md040Rule,        // fenced code blocks have a language
       md041Rule,        // first line must be a heading
       md047Rule,        // file ends with newline
       remarkLintMermaid // validate mermaid code blocks
     ],
     fixers: [
       md009Fixer,       // auto-fix trailing spaces
       md010Fixer,       // auto-fix hard tabs
       md047Fixer,       // auto-fix missing trailing newline
     ],
   }
   
   export default config

4. Run on your whole project

   npx crackdown lint docs/

Available packages

Package	Purpose
@crackdown/core	Core pipeline, programmatic API (lintString, lint, lintStringFix)
@crackdown/cli	CLI (crackdown lint, crackdown migrate, crackdown lsp)
@crackdown/plugin-mermaid	First-class Mermaid diagram validation
@crackdown/compat-markdownlint	18 markdownlint rule shims: MD001, MD005, MD007, MD009, MD010, MD012, MD013, MD022, MD024, MD025, MD026, MD031, MD032, MD033, MD034, MD040, MD041, MD047
@crackdown/lsp	Language Server for editor integration (Neovim, Zed, Helix)
@crackdown/vscode	VS Code extension

Next steps

• Read the CLI Reference for all commands and flags.
• Learn how to write your own plugin.
• Migrating from markdownlint? See the Migration Guide.