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 tmchow/tmc-marketplace --skill design-prototypinggit clone --depth 1 https://github.com/tmchow/tmc-marketplaceWrote 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/tmchow/tmc-marketplace/design-prototyping)<a href="https://agentmods.dev/skills/tmchow/tmc-marketplace/design-prototyping"><img src="https://agentmods.dev/badge/skills/tmchow/tmc-marketplace/design-prototyping/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/tmchow/tmc-marketplace/design-prototyping"><img src="https://agentmods.dev/badge/skills/tmchow/tmc-marketplace/design-prototyping.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 | $0.00044 | $0.03359 |
| Opus 5 | $0.00022 | $0.01680 |
| Sonnet 5 | $0.00009 | $0.00672 |
| Haiku 4.5 | $0.00004 | $0.00336 |
Grade A, and why
design-prototyping 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 12d 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 — 271 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design Prototyping
How to build a single self-contained design exploration variation file.
File Format
Every variation is a single HTML file with embedded metadata. The file is a complete page rendered inside an iframe in the gallery shell.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="https://cdn.tailwindcss.com"></script>
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<!-- Google Fonts <link> for specified fonts -->
<script type="application/json" id="variation-meta">
{
"id": "A1",
"family": "A",
"familyName": "...",
"name": "...",
"layoutType": "...",
"aesthetic": "...",
"description": "...",
"controls": [ /* control objects — see Control Schema below */ ]
}
</script>
<style>
:root {
/* All theme values as CSS custom properties */
}
:root * {
transition: color 0.3s ease, background-color 0.3s ease,
border-color 0.3s ease, padding 0.3s ease,
gap 0.3s ease, font-size 0.3s ease,
border-radius 0.3s ease, box-shadow 0.3s ease,
max-width 0.3s ease, width 0.3s ease;
}
</style>
</head>
<body>
<!-- Variation content -->
</body>
</html>
Metadata Block
The <script type="application/json" id="variation-meta"> block in <head> contains valid JSON with:
| Field | Type | Description |
|---|---|---|
id |
string | Variation code, e.g. "A1", "B2" |
family |
string | Family letter, e.g. "A" |
familyName |
string | Human-readable family name |
name |
string | Memorable variation name |
layoutType |
string | Layout description, e.g. "Sidebar + Cards" |
aesthetic |
string | Aesthetic description, e.g. "Clean Light" |
description |
string | One-line description of the variation |
controls |
array | 4-6 control objects (see schema below) |
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.
- 12d ago First seen · 271 lines · 44 tokens per session scan A 998ef36c8bfc
design-prototyping is a skill published in the GitHub repository tmchow/tmc-marketplace (22 stars, last pushed 6mo ago), licensed MIT. It adds 44 tokens to every session and 3,359 once invoked, about $0.0002 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.
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