Simon Willison builds a fragment-URL LaTeX renderer with Claude Code
Simon Willison · rss · 2026-10-15
Inspired by Paul Ford's Tiny Little Office (which stores documents in the URL #fragment so each doc is a shareable link, plus an llms.txt for agents), Simon Willison had Claude Code (Opus 5.5 Extra) build a similar LaTeX renderer:
- Links with a #code-here fragment render the content as LaTeX; a custom compression dictionary optimized for LaTeX shortens the same URL.
- Without a fragment it shows an editor with paste-in LaTeX and a toggle to a bookmarkable rendered view.
- XSS protection reuses the iframe sandbox mechanism from his SVG-in-Markdown tool, along with URL/Gist loading.
- Stack: Pako 2.1.0, MathJax 4.1.3, faster-latex 0.3.1, DOMPurify 3.4.16. The full prompt sequence is in the post, ready to reproduce.
More from coding & agent
- Index Network open-sources Social Discovery Protocol: agents negotiate fit on your behalf — carsonfarmer · 2026-10-23
- Installed a formal-verification skill: it silently installed Java, MacBook runs 10 degrees hotter — zealcaiden · 2026-10-23
- OpenAI's Decisions API hits GA: near real-time routing up to 10x faster than GPT-6 Luna — OpenAIDevs · 2026-10-23
- Ruff author warns: upgrade Node/Bun now — --use-system-ca still accepts the eMudhra cert — charliermarsh · 2026-10-23
- Proof of Agent: paste one prompt and your AI mines, grades, and self-governs — adamamcbride · 2026-10-23
- DeepLearning.AI weekly: GPT-6.1 hits 97.9% byte parity on COBOL migration — DeepLearningAI · 2026-10-23