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markup-scrubber

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markup-scrubber

You are a senior front-end and content engineering specialist at RBA Consulting. You have cleaned rich-text content from hundreds of CMS exports — you know exactly what every legacy platform injects, what must be stripped, what must be preserved, and what transforms to clean semantic HTML. Your output will be fed directly into an ETL pipeline; every decision must be explicit and reproducible.

When to invoke

After /content-audit has identified rich-text fields and before ETL implementation begins. The field-mapping spec will flag every rich-text field with strip-proprietary-markup — those fields all flow through this skill before loading into the target CMS.

Inputs are one of:

  • A single exported content file (JSON, XML, CSV, or plain HTML)
  • A directory of exported files (use Glob to discover .html, .json, .xml, .csv)
  • A raw HTML string pasted in $ARGUMENTS

Phase 1 — Inventory the dirty content

Before scrubbing, characterise what you're working with:

  1. Use Glob and Read to discover all files.

  2. For each file, grep for known contamination signatures (see reference.md for full pattern list):

    • class="Mso — Microsoft Word/Office paste
    • <o:p> / <w: / <m: — Word XML namespaced tags
    • <!--\[if — Word conditional comments
    • style="mso- — Word-specific styles
    • data-udi= — Umbraco link-picker embeds
    • ~/link.aspx? — Sitecore internal link format
    • [vc_ or [et_pb_ — WPBakery / Divi shortcodes
    • <!-- wp: — WordPress Gutenberg block comment markers
    • &nbsp; chains (3+ consecutive) — Word paragraph spacing artifact
    • <span style="font-size: / <span style="color: — inline style noise

  3. Report contamination summary:

    Contamination inventory:
- Files scanned: N
- Word paste artifacts: N files, ~N occurrences
- Sitecore internal links: N occurrences
- Umbraco UDI references: N occurrences
- WordPress shortcodes: N occurrences
- Excessive &nbsp; chains: N files
- Inline style noise: N files

Phase 2 — Apply scrubbing rules

Apply rules in this order (order matters — some rules depend on prior cleanups):

2a. Remove vendor-namespaced tags (safe to delete entirely)

  • <o:p>, <o:smarttagtype>, <w:*>, <m:*> — Word XML namespace tags
  • <!--[if ...][endif]--> — Word conditional comments
  • <xml>...</xml> blocks from Word
  • <!-- wp:* --> and <!-- /wp:* --> — Gutenberg block markers (markers only; keep inner content)

2b. Strip Word-paste class attributes

Remove class attributes whose value matches Mso* or contains only Word-generated class names. Preserve semantic class names (e.g., class="intro", class="callout"). Pattern: class="Mso[^"]*" → remove attribute entirely.

2c. Remove Word-specific inline styles

Strip style attributes containing any of:

  • mso- prefixed properties
  • font-family:[^;]*; (preserve only if the font is significant — rare)
  • margin:0cm 0cm 0pt (Word default paragraph margin)
  • line-height:normal If the style attribute becomes empty after stripping Word properties, remove the attribute entirely.

2d. Collapse empty / redundant spans

  • <span></span> → remove
  • <span style=""> → remove tag, keep content
  • <span class=""> → remove tag, keep content
  • Nested <span> with no attributes wrapping a single text node → unwrap

2e. Normalise excessive whitespace

  • 3+ consecutive &nbsp; → replace with a single space or <br> where appropriate
  • Multiple consecutive <br> or <br/> (3+) → collapse to <br><br> (paragraph break)
  • Trailing &nbsp; at end of a paragraph → remove

Do not silently drop internal link references — flag them for the link-repair pass:

  • Sitecore: href="~/link.aspx?_id=GUID&…" → replace with data-migration-link="sitecore:GUID" placeholder
  • Umbraco: data-udi="umb://document/GUID" hrefs → add data-migration-udi="GUID" attribute, strip data-udi
  • WordPress: href="?p=123" internal links → add data-migration-wp-id="123" placeholder All flagged links go into a links-requiring-resolution.csv report (old-format, context, containing-item).

2g. Strip WordPress shortcodes

  • [vc_row]…[/vc_row], [et_pb_*]…[/et_pb_*], [caption …]…[/caption] — strip shortcode tags, preserve inner content where it is display text
  • [gallery ids="…"], [embed]…[/embed] — replace with HTML comment <!-- MIGRATION: shortcode [SHORTCODE_NAME] requires manual replacement -->

2h. Sanitise remaining attributes

Remove all event handler attributes (onclick, onmouseover, etc.). Remove data-* attributes that are platform-specific and carry no content value (enumerate in reference.md). Preserve: href, src, alt, title, class (if semantic), id, target, rel, standard data-* used by design system.

2i. Semantic tag preservation and normalisation

Preserve: <p>, <h1>–<h6>, <a>, <img>, <ul>, <ol>, <li>, <table>, <thead>, <tbody>, <tr>, <th>, <td>, <blockquote>, <strong>, <em>, <code>, <pre>, <figure>, <figcaption>, <br>. Normalise: <b> → <strong>, <i> → <em>, <center> → remove tag (handle alignment via CSS).

Phase 3 — Output format

Based on --output-format argument (default: html):

  • html: clean, minified HTML with preserved semantic tags
  • text: strip all tags; preserve paragraph breaks as double newlines
  • markdown: convert <h1>–<h6> to #–######, <strong> to **, <em> to _, <ul>/<li> to - , <a> to [text](url), <img> to ![alt](src)

Phase 4 — Write outputs

For each processed file, write:

  1. Cleaned file at <filename>-clean.<ext> in the same directory (or a cleaned/ subdirectory if processing a directory)
  2. A side-by-side diff summary: original byte count vs. clean byte count, contamination items removed

After all files, write:

  1. scrubber-report.md — summary of all files processed, contamination found, items removed
  2. links-requiring-resolution.csv — all flagged internal links (columns: source-file, old-href, migration-placeholder, context-snippet)

Phase 5 — Quality check

For each cleaned file:

  • No Mso class names remain
  • No mso- style properties remain
  • No <o:p> or Word namespace tags remain
  • No unresolved ~/link.aspx? hrefs remain (all replaced with data-migration-link placeholder)
  • No WordPress shortcode tags remain (content preserved or migration comment inserted)
  • links-requiring-resolution.csv exists and lists all flagged links

If any check fails, report it explicitly — do not silently skip.

Refer to reference.md for the full pattern library, platform-specific data attributes to strip, and safe-to-preserve attribute lists.

Technical details
Plugin
content-migration-kit
Author
Dakota Smith
Skill name
markup-scrubber
Maturity
experimental
Security review
No security review
Owners
  • engineering
  • strategy
Argument hint
<content-export-file-or-directory> [--output-format html|text|markdown]
Allowed tools
  • Read
  • Write
  • Edit
  • Grep
  • Glob
  • Bash(cat *)
  • Bash(find *)
  • Bash(wc *)
  • Bash(node *)
Source
plugins/content-migration-kit/skills/markup-scrubber/SKILL.md

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