Md Linter

Lint, check, and auto-fix Markdown files — table of contents, broken links, YAML frontmatter validation, and formatting. Zero dependencies (Python stdlib).

Markdown Linter & Formatter

Lint and auto-format Markdown: trailing whitespace, frontmatter validation, TOC generation, external link checks.

Keywords: markdown, lint, format, toc, cli, docs, python, open-source, agent, automation, MIT

Part of the itsPremkumar Hermes / OpenClaw / Paperclip agent stack — 31 free, MIT-licensed, CI-tested agent-native tools.

What it does

Markdown drift (broken links, missing TOC, bad frontmatter) hurts docs and SEO. Markdown Linter & Formatter solves this: Lint and auto-format Markdown: trailing whitespace, frontmatter validation, TOC generation, external link checks.

Best for: Docs owners, open-source maintainers, and agents generating Markdown.

Features

• Lint a Markdown file
• Auto-format/normalize
• Validate frontmatter
• Generate a TOC
• Check external links

Install

bash

# Requires Python 3.8+. No pip install needed.
curl -O https://raw.githubusercontent.com/itsPremkumar/md-linter/main/md_linter.py
# Or copy the file anywhere — it's self-contained.

Quick start

bash

python md_linter.py self-test     # prove it works end-to-end
python md_linter.py check --help   # check subcommand
python md_linter.py toc --help   # toc subcommand
python md_linter.py links --help   # links subcommand
python md_linter.py frontmatter --help   # frontmatter subcommand
python md_linter.py format --help   # format subcommand

Use cases

1. Lint a Markdown file
2. Auto-format/normalize
3. Validate frontmatter
4. Generate a TOC
5. Check external links

Why choose this over alternatives

Alternative	Why this skill is better
markdownlint	Adds TOC generation + frontmatter validation.
Manual TOC	One command.
Broken links	External-link checker.

FAQ (SEO / AEO)

Q: TOC?
A: Yes — generate/insert a table of contents.

Q: External links?
A: --check-external validates them.

Q: Write?
A: --write reformats in place.

Q: Offline?
A: External-link check needs network; linting is offline.

Geo / local reach

Built and maintained by @itsPremkumar (Chennai, India · serving developers worldwide). Free for individuals and teams everywhere. Documentation in English; tool output is locale-neutral.

CI integration

yaml

# .github/workflows/verify.yml
name: Verify
on: [push]
jobs:
  verify:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Self-test md-linter
        run: python md_linter.py self-test

Support

Free + MIT-0 (free, modifiable, no attribution required). Sponsor if useful:

• GitHub Sponsors: https://github.com/sponsors/itsPremkumar
• Buy Me a Coffee: https://buymeacoffee.com/itsPremkumar

⭐ Star on GitHub