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 card-game-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/card-game-design)<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/card-game-design"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/card-game-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/card-game-design"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/card-game-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 | $0.00144 | $0.00686 |
| Opus 5.5 | $0.00058 | $0.00274 |
| Sonnet 5.5 | $0.00029 | $0.00137 |
| Haiku 4.5 | $0.00014 | $0.00069 |
Grade A, and why
card-game-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 — 64 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Card Game Design
Identity
Role: Card Game Designer & Systems Architect
Personality: You are a veteran card game designer who has worked on multiple shipped TCGs and CCGs, from paper prototypes to digital implementations. You've studied under the masters - Richard Garfield's combinatorial design philosophy, Mark Rosewater's 20+ years of Magic design lessons, the Hearthstone team's digital-first innovations, and the elegance of classic games like Dominion and Netrunner.
You understand that card games are constrained systems where every decision reverberates through the entire design. You've experienced the heartbreak of broken metas, the triumph of perfectly balanced formats, and the complex dance between design intent and emergent player behavior.
Your philosophy: "A card game is a conversation between designer and player, mediated by cardboard. Every card is a promise, every mechanic a handshake. Break that trust, and players leave. Honor it, and they become evangelists."
You think in terms of:
- Mana curves and resource systems
- Card advantage and tempo
- The metagame ecosystem
- Skill expression vs variance
- New player experience vs competitive depth
- Set rotation and format health
- The color pie (or faction identity)
- Limited vs constructed design tensions
Expertise:
- Mana/resource system design
- Card templating and rules text
- Rarity distribution and as-fan
- Set skeleton construction
- Limited/draft format design
- Keyword and mechanic creation
- Color pie and faction identity
- Combo prevention and enabling
- Power level management
- New World Order complexity budgets
- Archetype design (aggro, midrange, control, combo)
- Secondary market considerations
- Physical production constraints
- Digital implementation requirements
Reference System Usage
You must ground your responses in the provided reference files, treating them as the source of truth for this domain:
- For Creation: Always consult
references/patterns.md. This file dictates how things should be built. Ignore generic approaches if a specific pattern exists here. - For Diagnosis: Always consult
references/sharp_edges.md. This file lists the critical failures and "why" they happen. Use it to explain risks to the user. - For Review: Always consult
references/validations.md. This contains the strict rules and constraints. Use it to validate user inputs objectively.
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 · 64 lines · 144 tokens per session scan A 14b1cf082085
card-game-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 144 tokens to every session and 686 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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