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 skills add tmj-90/gaffer --skill frontend-foundationsgit clone --depth 1 https://github.com/tmj-90/gafferWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/tmj-90/gaffer/frontend-foundations)<a href="https://agentmods.dev/skills/tmj-90/gaffer/frontend-foundations"><img src="https://agentmods.dev/badge/skills/tmj-90/gaffer/frontend-foundations/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/tmj-90/gaffer/frontend-foundations"><img src="https://agentmods.dev/badge/skills/tmj-90/gaffer/frontend-foundations.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What 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 5.1 | $0.00126 | $0.01203 |
| Opus 5.5 | $0.00050 | $0.00481 |
| Sonnet 5.5 | $0.00025 | $0.00241 |
| Haiku 4.5 | $0.00013 | $0.00120 |
Grade A, and why
frontend-foundations 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 21d 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 — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend foundations — the UI quality floor
The frontend companion to engineering-craft: craft holds the code bar, this holds the
surface bar. It is a short floor to check on every UI change, not the full treatment —
each item names the skill that holds the depth. It never licenses extra chrome or
animation the ticket did not ask for (the minimalism skill): meet the bar with the least
markup and the fewest dependencies.
The floor
- Semantic and operable. Native elements (
button,a href,label,nav,main,dialog), oneh1, keyboard-operable with a visible:focus-visiblestyle, text alternatives on meaningful images and icon-only buttons, colour never the only signal. Depth: thefrontend-a11yskill (WCAG 2.2 AA). - Tokens, not magic values. Colour, spacing, type, radius, shadow, duration from the
repo's tokens or theme. A raw hex or
pxfont size in a component where a token exists is the frontend form of duplicated logic. Depth: thedesign-systemskill. - The repo's components and styling system. Reuse primitives before writing new
ones; no second UI library, CSS approach or icon set. Depth: the
frontend-componentskill. - Every state the ACs imply. Loading (at final size), empty with a next action,
error with recovery, plus hover / focus / active / disabled. A missing empty or error
state is an unfinished component. Server-state depth: the
frontend-data-fetchingskill. - Intentional hierarchy. One clear primary action and a type scale with real contrast
between levels; not a uniform grid of identical cards. If it looks like an unmodified
starter template, it is not done. Depth: the
frontend-designskill. - Motion that explains, on the compositor. Animate
transformandopacity, notwidth/height/top/margin; 150–300 ms for UI transitions; non-essential motion inside@media (prefers-reduced-motion: no-preference). - Responsive and overflow-safe. No horizontal scroll from 320 CSS px up, targets at
least 24×24 CSS px, zoom not disabled. Depth: the
frontend-responsiveskill. - Text is data-ready. User-visible strings go through the repo's i18n layer if it has
one; dates and numbers are formatted by locale. Depth: the
i18n-l10nskill.
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.
- 21d ago Changed · +10 lines · +4 tokens per session 490c1797d29c
- 1mo ago First seen · 65 lines · 122 tokens per session scan A 41e563f5cda1
frontend-foundations is a skill published in the GitHub repository tmj-90/gaffer (2 stars, last pushed 22d ago), licensed Apache-2.0. It adds 126 tokens to every session and 1,203 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-08-31.
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