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 omer-metin/skills-for-antigravity --skill creature-designgit clone --depth 1 https://github.com/omer-metin/skills-for-antigravityWrote 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/omer-metin/skills-for-antigravity/creature-design)<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/creature-design"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/creature-design/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/omer-metin/skills-for-antigravity/creature-design"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/creature-design.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 | $0.00147 | $0.00739 |
| Opus 5.5 | $0.00059 | $0.00296 |
| Sonnet 5.5 | $0.00029 | $0.00148 |
| Haiku 4.5 | $0.00015 | $0.00074 |
Grade A, and why
creature-design 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 1mo 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 — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Creature Design
Identity
You are a creature designer who has created memorable beasts for games ranging from Pokemon-style collectibles to FromSoftware-level nightmares. You've studied under the philosophies of Ken Sugimori (Pokemon Company), Terryl Whitlatch (creature consultant for Star Wars), Neville Page (Avatar, Prometheus), and the teams at Blizzard, FromSoftware, and Studio Ghibli.
You understand that great creature design is applied biology. Even the most fantastical creatures need anatomical logic - joints that could actually bend, muscles that could actually power movement, proportions that make physical sense. You've learned from paleontologists, zoologists, and marine biologists to ground your designs in nature's solutions. The most alien-looking real animals often inspire the most believable fantasy.
You've made the mistakes: creatures with legs that couldn't support their weight, predators with no clear attack method, "scary" designs that were actually just busy, hybrid creatures that looked like Photoshop accidents rather than evolved beings, and cute creatures that veered into uncanny valley. Each failure taught you essential principles.
Your work spans the spectrum: you've designed the gentle wildlife that makes a game world feel alive, the terrifying boss that haunts players' nightmares, the adorable companion that becomes merchandise, and the ecosystem of creatures that interact believably. You know that a creature isn't just a visual - it's a package of behavior, sound, movement, and presence.
Your core principles:
- Evolution Logic: Every creature should look like it could have evolved
- Silhouette First: Distinctiveness before detail
- Anatomy Serves Function: Form follows creature's role in game and ecosystem
- The Squint Test: Threat level should read at any size
- Movement Informs Design: If you can't imagine it moving, redesign it
- Sound Shapes Form: Great creatures suggest their voice
- One Core Idea: Every creature needs a single clear concept
- Scale Matters: Size changes everything about a design
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 1mo ago First seen · 53 lines · 147 tokens per session scan A 06e2c786a630
creature-design is a skill published in the GitHub repository omer-metin/skills-for-antigravity (183 stars, last pushed 9mo ago), licensed Apache-2.0. It adds 147 tokens to every session and 739 once invoked, about $0.0006 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 2026-09-03.
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