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 MauricioPerera/llms-txt-skills --skill placeholdergit clone --depth 1 https://github.com/MauricioPerera/llms-txt-skillsWrote 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/mauricioperera/llms-txt-skills/placeholder)<a href="https://agentmods.dev/skills/mauricioperera/llms-txt-skills/placeholder"><img src="https://agentmods.dev/badge/skills/mauricioperera/llms-txt-skills/placeholder/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/mauricioperera/llms-txt-skills/placeholder"><img src="https://agentmods.dev/badge/skills/mauricioperera/llms-txt-skills/placeholder.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 | $0.00039 | $0.00797 |
| Opus 5 | $0.00019 | $0.00398 |
| Sonnet 5 | $0.00008 | $0.00159 |
| Haiku 4.5 | $0.00004 | $0.00080 |
Grade A, and why
placeholder 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.
This is a copy
100% identical to placeholder — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.
placeholder
Build URLs for the placeholder-img API to embed mockup images in HTML, CSS, or design prototypes.
When to use
- User asks for a placeholder image of size W×H.
- User is prototyping a UI and needs a dummy
<img>source. - User wants a colored block of a known aspect ratio as a background.
Do NOT use this skill for production images, photography, or when the user wants real content — this generates blank colored SVGs with the dimensions drawn as text.
When to prefer this over alternatives
- Over CSS color blocks (
<div style="background:#ccc;width:400px;height:300px">): when the mockup needs to behave like a real image — responsive aspect ratio,<img>semantics for alt text and lazy-loading, usable as<img srcset>orbackground-imageinterchangeably. - Over third-party services like
placehold.coorvia.placeholder.com: when the user wants a self-hosted source with no third-party dependency, guaranteed immutable cache (max-age=31536000, immutable), and a stable domain they control. - Over inline
data:image/svg+xmlURIs: when the mockup is referenced from more than one place, when HTML readability matters, or when the dimensions are dynamic and embedding SVG string-templates would clutter the code.
If none of the above apply — e.g., the user is already using a design system with built-in skeleton components, or a CSS block is genuinely sufficient — prefer the simpler option and do not call this API.
Base URL
https://img.automators.work
Build the URL
{base}/{width}x{height}[?bg={hex6}]
width,height: integers in px, each ≤ 4000.bg(optional): 6-digit hex without#. Defaults tocccccc. Invalid values silently fall back to the default.
Examples
| Intent | URL |
|---|---|
| Generic 400×300 placeholder | https://img.automators.work/400x300 |
| Dark-blue banner | https://img.automators.work/1200x400?bg=1e3a5f |
| Square brand tile | https://img.automators.work/512x512?bg=f97316 |
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 · 76 lines · 39 tokens per session scan A f427124e22c7
placeholder is a skill published in the GitHub repository MauricioPerera/llms-txt-skills (2 stars, last pushed 13d ago), licensed MIT. It adds 39 tokens to every session and 797 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to placeholder, differing in 0 lines, and is treated as a copy.
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Turn ordinary text plans into rich interactive visual plans with diagrams, file maps, annotated code, open questions, and UI/prototype review when useful.
visual-edit
Open a running local app in Design overview mode as URL-backed iframe screens for visual editing, flow review, duplication, and route-state exploration. Use when the user asks to inspect, compare, or edit a real local app visually in Design.
muapi-ui-design
Generate high-fidelity UI/UX mockups for mobile and web apps using Atomic Design principles — creates wireframes and design systems via muapi.ai.