# LLM Safety

URL: /docs/extending/llm-safety/
Section: extending
Tags: extending, llm, sanitize, safety, rag

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LLM Safety When sending Markdown to an LLM (RAG retrieval, user-provided docs, context windows), you should sanitize untrusted content and render to a safe, structured format. Patitas provides a parse → sanitize → render pipeline for this. Pipeline from patitas import parse, sanitize, render_llm from patitas.sanitize import llm_safe # 1. Parse doc = parse(user_content) # 2. Sanitize (strip HTML, dangerous URLs, zero-width chars) clean = sanitize(doc, policy=llm_safe) # 3. Render to LLM-friendly plain text safe_text = render_llm(clean, source=user_content) What Gets Removed The llm_safe policy strips: HTML — All HtmlBlock and HtmlInline nodes (prevents script injection, hidden content) Dangerous URLs — Links and images with javascript:, data:, vbscript: schemes Zero-width / bidi characters — Trojan Source mitigation (invisible Unicode that can change display order or hide malicious content) Pre-built Policies Policy Strips Use case llm_safe HTML, dangerous URLs, zero-width LLM context (RAG, retrieval) web_safe Same as llm_safe (alias) Web display of untrusted content strict llm_safe + images (→ alt text) + raw code blocks Maximum reduction from patitas.sanitize import llm_safe, web_safe, strict clean = sanitize(doc, policy=llm_safe) # RAG, retrieval clean = sanitize(doc, policy=web_safe) # User content on web (same as llm_safe) clean = sanitize(doc, policy=strict) # Minimal text only Custom Policies Compose policies with the | operator: from patitas.sanitize import strip_html, strip_dangerous_urls, normalize_unicode, allow_url_schemes # Only https and mailto custom = strip_html | strip_dangerous_urls | normalize_unicode | allow_url_schemes("https", "mailto") clean = sanitize(doc, policy=custom) Available building blocks: strip_html, strip_html_comments, strip_dangerous_urls, normalize_unicode, strip_images, strip_raw_code, allow_url_schemes(*schemes). render_llm Output render_llm() produces structured plain text with explicit labels: Code blocks: [code:python]\n...\n[/code] Math: [math] ... [/math] Images: [image: alt text] HtmlBlock / HtmlInline: skipped (not rendered) No raw HTML is emitted. The format is predictable and parseable for downstream tools. Example Run the full pipeline: python examples/llm_safety/llm_safe_context.py This demonstrates parse → sanitize → render_llm on sample content with HTML, dangerous links, and zero-width characters. See Also API Reference — render_llm(), sanitize(), Policy Examples — Runnable examples in the repo

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