placeholder

placeholder is a skill for Claude Code, Codex from MauricioPerera/llms-txt-skills. It costs 39 tokens per session (797 once invoked), scanned A, original, MIT.

A tool for creating blank SVG images with chosen dimensions and colors. SVG is an image format that stays sharp at different sizes.

In plain words
What is it for?
Use it for UI mockups, dummy image areas, colored placeholders, responsive image examples, and HTML or CSS prototypes.
Why use it?
It gives prototypes image-shaped content without needing real photography or a separate image service. The result can be used wherever an ordinary image source is expected.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for UI mockups, dummy image areas, colored placeholders, responsive image examples, and HTML or CSS prototypes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mauricioperera/llms-txt-skills/default
Install

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.

Any agent
npx skills add MauricioPerera/llms-txt-skills --skill default
Clone the repo
git clone --depth 1 https://github.com/MauricioPerera/llms-txt-skills

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for placeholder

README.md
[![agentmods](https://agentmods.dev/badge/skills/mauricioperera/llms-txt-skills/default/github.svg)](https://agentmods.dev/skills/mauricioperera/llms-txt-skills/default)
Your own site
<a href="https://agentmods.dev/skills/mauricioperera/llms-txt-skills/default"><img src="https://agentmods.dev/badge/skills/mauricioperera/llms-txt-skills/default/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.

agentmods 80×15 button for placeholder

Your own site · 80×15
<a href="https://agentmods.dev/skills/mauricioperera/llms-txt-skills/default"><img src="https://agentmods.dev/badge/skills/mauricioperera/llms-txt-skills/default.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 797 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce 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

Measured 11d ago against content hash f427124e22c7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

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 11d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.well-known/skills/default/SKILL.md · 76 lines

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> or background-image interchangeably.
  • Over third-party services like placehold.co or via.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+xml URIs: 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 to cccccc. 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

Read the full file on GitHub · 76 lines

Changes

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.

  1. 11d ago First seen · 76 lines · 39 tokens per session scan A f427124e22c7

Subscribe to this mod's changes

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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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