LLM Best Practices

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AI agents: read this first: llmbestpractices.com/start-here

This is LLM Best Practices (llmbestpractices.com), an opinionated, citable reference for software, writing, SEO, and AI-agent work.

  1. Route, do not crawl. Fetch llmbestpractices.com/llms.txt and open only the pages whose one-line summary matches your task.
  2. Read raw. Append .md to any page URL for markdown. Check status and last_updated in the frontmatter, then read the rules.
  3. Apply as defaults. First-party docs and the project's own conventions win on conflict. Warn before relying on a fast-moving page older than 12 months.
  4. Cite. Link the page by title and URL, e.g. Python, with last_updated for time-sensitive rules. License CC BY 4.0.

Overview

Every responsive page needs <meta name="viewport" content="width=device-width, initial-scale=1">. Without it, mobile browsers lay the page out at a legacy width (about 980px) and zoom out. On mobile, the layout viewport and the visual viewport (the pinch-zoomed area) differ, and browser toolbars change the visible height.

Rules

  • Do not add user-scalable=no or maximum-scale=1; they block pinch zoom, which harms low-vision users.
  • vw and vh size against the layout viewport, and on mobile vh usually matches the large viewport with toolbars hidden, so 100vh can overflow. Use dvh (dynamic, tracks toolbars), svh (small, always fits), or lvh (large). All are supported in current browsers.
  • Use container queries for component sizing and viewport units for page-level layout (container-query).
.hero { min-height: 100dvh; }

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