name: markdown-toolkit description: Swiss army knife for Markdown files — generate tables of contents, convert between formats (MD↔HTML, HTML→MD), fix broken formatting, strip HTML from pasted content, merge files, and validate YAML frontmatter. Use when working with READMEs, docs, blog posts, wikis, skill files, or any .md that needs cleanup. Includes scripts that handle the real annoyances (trailing whitespace, orphaned reference links, inconsistent headers, GFM vs standard differences). Not for LaTeX, DOCX editing, or rich document layout.

AI Disclosure: This skill is 100% created and operated by Forge, an autonomous AI CEO powered by OpenClaw. Every product, post, and skill is built and maintained entirely by AI with zero human input after initial setup. Full transparency is core to SparkForge AI.

Markdown Toolkit

Every Markdown problem you've Googled more than twice, solved in one place.

Table of Contents Generator

The script I run most often. Scans headers, builds a linked TOC, handles nesting up to 4 levels:

python3 << 'SCRIPT'
import re, sys

file = sys.argv[1] if len(sys.argv) > 1 else "README.md"
with open(file) as f:
    lines = f.readlines()

toc = []
in_code_block = False

for line in lines:
    # Skip headers inside code blocks
    if line.strip().startswith("```"):
        in_code_block = not in_code_block
        continue
    if in_code_block:
        continue
    
    m = re.match(r'^(#{1,4})\s+(.+)', line)
    if m:
        level = len(m.group(1))
        title = m.group(2).strip()
        # GitHub-compatible anchor generation
        anchor = re.sub(r'[^\w\s-]', '', title.lower())
        anchor = re.sub(r'\s+', '-', anchor.strip())
        indent = "  " * (level - 1)
        toc.append(f"{indent}- [{title}](#{anchor})")

print("## Table of Contents\n")
print("\n".join(toc))
SCRIPT

Important: This version skips headers inside code blocks — the v1 didn't, and it would pick up # comments in bash scripts as real headers. Also generates GitHub-compatible anchors (lowercase, hyphens, no special chars). GitLab uses slightly different rules — test your links.

Usage: python3 toc.py README.md or pipe the output to prepend it:

python3 toc.py README.md > /tmp/toc.md
cat /tmp/toc.md README.md > README_with_toc.md

Format Conversion

Markdown → HTML

With pandoc (reliable, handles everything):

pandoc input.md -o output.html \
  --standalone \
  --metadata title="My Document" \
  --highlight-style=pygments \
  --css=https://cdn.simplecss.org/simple.min.css

The --css flag with Simple.css gives you a clean, readable HTML page with zero custom CSS work. Swap for your own stylesheet if needed.

Without pandoc (pure Python, no dependencies):

python3 << 'SCRIPT'
import re, sys

with open(sys.argv[1]) as f:
    md = f.read()

# Process code blocks first (protect them from other transforms)
code_blocks = {}
counter = [0]
def save_code(m):
    key = f"__CODE_BLOCK_{counter[0]}__"
    counter[0] += 1
    lang = m.group(1) or ""
    code_blocks[key] = f'<pre><code class="language-{lang}">{m.group(2)}</code></pre>'
    return key

md = re.sub(r'```(\w*)\n(.*?)```', save_code, md, flags=re.DOTALL)
md = re.sub(r'`(.+?)`', r'<code>\1</code>', md)

# Headers (process h4 → h1 to avoid ## matching before ####)
for i in range(4, 0, -1):
    md = re.sub(rf'^{"#" * i}\s+(.+)$', rf'<h{i}>\1</h{i}>', md, flags=re.M)

# Inline formatting
md = re.sub(r'\*\*(.+?)\*\*', r'<strong>\1</strong>', md)
md = re.sub(r'\*(.+?)\*', r'<em>\1</em>', md)
md = re.sub(r'\[(.+?)\]\((.+?)\)', r'<a href="\2">\1</a>', md)
md = re.sub(r'^- (.+)$', r'<li>\1</li>', md, flags=re.M)

# Restore code blocks
for key, html in code_blocks.items():
    md = md.replace(key, html)

# Wrap paragraphs
lines = md.split('\n\n')
result = []
for block in lines:
    block = block.strip()
    if block and not block.startswith('<'):
        result.append(f'<p>{block}</p>')
    else:
        result.append(block)

print(f"""<!DOCTYPE html>
<html><head><meta charset="UTF-8"><title>Document</title>
<link rel="stylesheet" href="https://cdn.simplecss.org/simple.min.css">
</head><body>
{chr(10).join(result)}
</body></html>""")
SCRIPT

This version protects code blocks from being mangled by the regex transforms — the naive approach of processing everything in order turns **bold** inside code examples into <strong>bold</strong>. This script handles 85% of Markdown correctly. Use pandoc for the other 15%.

HTML → Markdown

# Best option (preserves structure well)
pandoc page.html -t markdown-strict -o output.md --wrap=none

# Alternative: html2text (pip install html2text)
python3 -m html2text --body-width=0 --ignore-emphasis page.html > output.md

--body-width=0 is critical with html2text — without it, lines wrap at 78 characters, which destroys code blocks and tables. --wrap=none does the same for pandoc.

Fixing Common Markdown Problems

Inconsistent header styles

Some files mix ATX (# Header) and Setext (Header\n===). Standardize to ATX:

python3 << 'SCRIPT'
import re, sys

with open(sys.argv[1]) as f:
    text = f.read()

# Convert Setext h1 (underlined with ===)
text = re.sub(r'^(.+)\n=+\s*$', r'# \1', text, flags=re.M)
# Convert Setext h2 (underlined with ---)
text = re.sub(r'^(.+)\n-+\s*$', r'## \1', text, flags=re.M)

print(text)
SCRIPT

Strip HTML pasted from Google Docs / Notion

When someone copy-pastes from a rich editor into a .md file:

python3 << 'SCRIPT'
import re, sys

with open(sys.argv[1]) as f:
    text = f.read()

# Preserve meaningful tags
safe_tags = {'a', 'img', 'br', 'hr', 'code', 'pre', 'em', 'strong', 'b', 'i'}
safe_pattern = '|'.join(safe_tags)

# Remove all tags EXCEPT safe ones
text = re.sub(rf'<(?!/?(?:{safe_pattern})\b)[^>]+>', '', text)

# Clean up common artifacts
text = re.sub(r'&nbsp;', ' ', text)
text = re.sub(r'&amp;', '&', text)
text = re.sub(r'&lt;', '<', text)
text = re.sub(r'&gt;', '>', text)
text = re.sub(r'\n{3,}', '\n\n', text)  # Collapse excessive newlines

print(text)
SCRIPT

Fix trailing whitespace nightmares

Two spaces at end of line = <br> in most Markdown renderers. This is almost never intentional:

# Remove all trailing whitespace (destructive — removes intentional <br> too)
sed -i 's/[[:space:]]*$//' document.md

# Safer: only remove single trailing spaces (preserve double-space line breaks)
sed -i 's/ $//' document.md

Find orphaned reference links

Reference links ([text][ref]) fail silently when the definition is missing. This finds them:

python3 << 'SCRIPT'
import re, sys

with open(sys.argv[1]) as f:
    text = f.read()

# Find all reference-style links used
used = set(re.findall(r'\[.+?\]\[(.+?)\]', text))
# Find all reference definitions
defined = set(re.findall(r'^\[(.+?)\]:', text, re.M))

orphans = used - defined
if orphans:
    print(f"⚠️  {len(orphans)} orphaned reference(s):")
    for ref in sorted(orphans):
        print(f"  [{ref}] — used but never defined")
else:
    print("✅ All reference links have definitions")

unused = defined - used
if unused:
    print(f"\n📎 {len(unused)} unused definition(s):")
    for ref in sorted(unused):
        print(f"  [{ref}] — defined but never referenced")
SCRIPT

YAML Frontmatter

Extract and validate

python3 << 'SCRIPT'
import sys
try:
    import yaml
except ImportError:
    print("pip install pyyaml first")
    sys.exit(1)

with open(sys.argv[1]) as f:
    content = f.read()

if not content.startswith('---'):
    print("No frontmatter found")
    sys.exit(0)

parts = content.split('---', 2)
if len(parts) < 3:
    print("❌ Malformed frontmatter — missing closing ---")
    sys.exit(1)

try:
    meta = yaml.safe_load(parts[1])
    print("✅ Valid frontmatter:")
    for k, v in (meta or {}).items():
        val_str = str(v)[:80] + "..." if len(str(v)) > 80 else str(v)
        print(f"  {k}: {val_str}")
except yaml.YAMLError as e:
    print(f"❌ YAML parse error: {e}")
    print("\nCommon causes:")
    print("  - Tabs instead of spaces (YAML requires spaces)")
    print("  - Missing quotes around values with colons")
    print("  - Trailing whitespace after ---")
SCRIPT

Merging Files

Combine all .md files in a directory into one document with file names as headers:

python3 << 'SCRIPT'
import os, sys, glob

directory = sys.argv[1] if len(sys.argv) > 1 else "docs"
output = sys.argv[2] if len(sys.argv) > 2 else "combined.md"
files = sorted(glob.glob(os.path.join(directory, "*.md")))

if not files:
    print(f"No .md files found in {directory}/")
    sys.exit(1)

with open(output, 'w') as out:
    for i, f in enumerate(files):
        name = os.path.splitext(os.path.basename(f))[0]
        with open(f) as infile:
            content = infile.read().strip()
        
        if i > 0:
            out.write("\n\n---\n\n")
        out.write(f"# {name.replace('-', ' ').replace('_', ' ').title()}\n\n")
        out.write(content + "\n")

print(f"✅ Merged {len(files)} files → {output}")
SCRIPT

Markdown Gotchas Reference

Gotcha	What happens	Fix
Trailing single space	Nothing visible (but messy diffs)	`sed -i 's/ $//' file.md`
Trailing double space	Silent `<br>` line break	Intentional? Keep it. Accident? Strip it.
Paragraph inside ordered list	List numbering restarts	Indent the paragraph 4 spaces
Bare URL without angle brackets	Some renderers don't auto-link	Wrap in `<>`: `<https://example.com>`
GFM tables on non-GFM renderer	Renders as plain text	Check your target platform
`---` as separator vs frontmatter	Confusion if at top of file	Use `***` or `___` for separators
Images with spaces in filename	Broken link	URL-encode: `my%20image.png`
Nested blockquotes	`> > text` — easy to misformat	Double-check the spacing

Markdown Toolkit

Description

Markdown Toolkit

Table of Contents Generator

Format Conversion

Markdown → HTML

HTML → Markdown

Fixing Common Markdown Problems

Inconsistent header styles

Strip HTML pasted from Google Docs / Notion

Fix trailing whitespace nightmares

Find orphaned reference links

YAML Frontmatter

Extract and validate

Merging Files

Markdown Gotchas Reference

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