Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/vercel-labs/web-interface-guidelines/agents-mdgit clone --depth 1 https://github.com/vercel-labs/web-interface-guidelinesWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.01887 | $0.01887 |
| Opus 5 | $0.00944 | $0.00944 |
| Sonnet 5 | $0.00377 | $0.00377 |
| Haiku 4.5 | $0.00189 | $0.00189 |
Grade A, and why
web-interface-guidelines AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Concise rules for building accessible, fast, delightful UIs. Use MUST/SHOULD/NEVER to guide decisions.
Interactions
Keyboard
- MUST: Full keyboard support per WAI-ARIA APG
- MUST: Visible, unobscured focus rings (
:focus-visible; group with:focus-within); sticky/fixed elements never cover focus - MUST: Manage focus (trap, move, return) per APG patterns
- NEVER:
outline: nonewithout visible focus replacement
Targets & Input
- MUST: Hit target ≥24px (mobile ≥44px); if visual <24px, expand hit area
- MUST: Mobile
<input>font-size ≥16px to prevent iOS zoom - NEVER: Disable browser zoom (
user-scalable=no,maximum-scale=1) - MUST:
touch-action: manipulationto prevent double-tap zoom - SHOULD: Set
-webkit-tap-highlight-colorto match design
Forms
- MUST: Hydration-safe inputs (no lost focus/value)
- NEVER: Block paste in
<input>/<textarea> - MUST: Loading buttons show spinner and keep original label
- MUST: Enter submits focused input; in
<textarea>, ⌘/Ctrl+Enter submits - MUST: Keep submit enabled until request starts; then disable with spinner
- MUST: Accept free text, validate after—don't block typing
- MUST: Allow incomplete form submission to surface validation
- MUST: Errors inline next to fields; on submit, focus first error
- MUST:
autocomplete+ meaningfulname; correcttypeandinputmode - SHOULD: Disable spellcheck for emails/codes/usernames
- SHOULD: Placeholders end with
…and show example pattern - MUST: Warn on unsaved changes before navigation
- MUST: Compatible with password managers & 2FA; allow pasting codes
- MUST: Trim values to handle text expansion trailing spaces
- MUST: No dead zones on checkboxes/radios; label+control share one hit target
State & Navigation
- MUST: URL reflects state (deep-link filters/tabs/pagination/expanded panels)
- MUST: Back/Forward restores scroll position
- MUST: Links use
<a>/<Link>for navigation (support Cmd/Ctrl/middle-click) - NEVER: Use
<div onClick>for navigation
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 156 lines · 1,887 tokens per session scan A 113bce3da621
web-interface-guidelines AGENTS.md is an instructions file published in the GitHub repository vercel-labs/web-interface-guidelines (834 stars, last pushed 15d ago), licensed MIT. It adds 1,887 tokens to every session, about $0.0094 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
gradio AGENTS.md
AGENTS.md instructions for gradio-app/gradio, covering agents.md, repository structure, pull request rules, code style and agentic contribution policy.
ui-components AGENTS.md
Instructions for starc007/ui-components, covering beui v2 — agent guide, commands, layout, component catalog and components (motion category — primitives).
unity-ui-toolkit-design-system AGENTS.md
Instructions for sinanata/unity-ui-toolkit-design-system, covering agents.md, what this project is, golden rules (do not violate), use the design system in your project and repository layout.
oh-my-design CLAUDE.md
Instructions for kwakseongjae/oh-my-design, a project described as: Give your AI coding agent a design system. One command installs 400+ quality-graded company DESIGN.md references + skills into Claude Code, Codex, Cursor, and OpenCode. Free, MIT, zero AI calls.
unity-ui-toolkit-design-system copilot-instructions.md
Instructions for sinanata/unity-ui-toolkit-design-system: This repository follows the cross-tool AGENTS.md standard. Read /AGENTS.md for the full guide: the ds- class naming, the token rules, the load-bearing USS import order, build and preview commands, and the pull-request checklist.
gpui-toolkit AGENTS.md
Instructions for pierreaubert/gpui-toolkit, covering gpui toolkit - agent's guide, forms, keyboard management, mouse management and common patterns.