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 TraftG/opencode-game-studio --skill design-systemgit clone --depth 1 https://github.com/TraftG/opencode-game-studioWrote 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/traftg/opencode-game-studio/design-system)<a href="https://agentmods.dev/skills/traftg/opencode-game-studio/design-system"><img src="https://agentmods.dev/badge/skills/traftg/opencode-game-studio/design-system/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/traftg/opencode-game-studio/design-system"><img src="https://agentmods.dev/badge/skills/traftg/opencode-game-studio/design-system.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 | $0.00045 | $0.04161 |
| Opus 5.5 | $0.00018 | $0.01664 |
| Sonnet 5.5 | $0.00009 | $0.00832 |
| Haiku 4.5 | $0.00005 | $0.00416 |
Grade A, and why
design-system 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- design-system — 98% identical, 2 lines differ
- design-system — 98% identical, 2 lines differ
How it starts
The opening of the file, as written. The whole thing — 497 lines — stays where its author put it; the contents beside it link to each section on GitHub.
When this skill is invoked:
1. Parse Arguments & Validate
A system name argument is required. If missing, fail with:
"Usage:
/design-system <system-name>— e.g.,/design-system combat-systemRun/map-systemsfirst to create the systems index, then use this skill to write individual system GDDs."
Normalize the system name to kebab-case for the filename (e.g., "combat system"
becomes combat-system).
2. Gather Context (Read Phase)
Read all relevant context before asking the user anything. This is the skill's primary advantage over ad-hoc design — it arrives informed.
2a: Required Reads
- Game concept: Read
design/gdd/game-concept.md— fail if missing:"No game concept found. Run
/brainstormfirst." - Systems index: Read
design/gdd/systems-index.md— fail if missing:"No systems index found. Run
/map-systemsfirst to map your systems." - Target system: Find the system in the index. If not listed, warn:
"[system-name] is not in the systems index. Would you like to add it, or design it as an off-index system?"
2b: Dependency Reads
From the systems index, identify:
- Upstream dependencies: Systems this one depends on. Read their GDDs if they exist (these contain decisions this system must respect).
- Downstream dependents: Systems that depend on this one. Read their GDDs if they exist (these contain expectations this system must satisfy).
For each dependency GDD that exists, extract and hold in context:
- Key interfaces (what data flows between the systems)
- Formulas that reference this system's outputs
- Edge cases that assume this system's behavior
- Tuning knobs that feed into this system
2c: Optional Reads
- Game pillars: Read
design/gdd/game-pillars.mdif it exists - Existing GDD: Read
design/gdd/[system-name].mdif it exists (resume, don't restart from scratch) - Related GDDs: Glob
design/gdd/*.mdand read any that are thematically related (e.g., if designing "status-effects", also read "combat-system" even if it's not a direct dependency)
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 · 497 lines · 45 tokens per session scan A ad9c1f18cc7e
design-system is a skill published in the GitHub repository TraftG/opencode-game-studio (45 stars, last pushed 6mo ago), licensed MIT. It adds 45 tokens to every session and 4,161 once invoked, about $0.0002 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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