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 rondorkerin/gamestack --skill game-design-fundamentalsgit clone --depth 1 https://github.com/rondorkerin/gamestackWrote 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/rondorkerin/gamestack/game-design-fundamentals)<a href="https://agentmods.dev/skills/rondorkerin/gamestack/game-design-fundamentals"><img src="https://agentmods.dev/badge/skills/rondorkerin/gamestack/game-design-fundamentals/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/rondorkerin/gamestack/game-design-fundamentals"><img src="https://agentmods.dev/badge/skills/rondorkerin/gamestack/game-design-fundamentals.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 | $0.00156 | $0.00634 |
| Opus 5 | $0.00078 | $0.00317 |
| Sonnet 5 | $0.00031 | $0.00127 |
| Haiku 4.5 | $0.00016 | $0.00063 |
Grade A, and why
game-design-fundamentals 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.
How it starts
The opening of the file, as written. The whole thing — 38 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Game-Design Fundamentals
The bedrock principles every other skill in the pack assumes. If a design decision feels wrong and you're not sure why, the answer is usually here.
When to use this
- Deciding whether a mechanic, system, or choice is actually fun (not just functional)
- Balancing — hunting dominant strategies, no-brainer options, difficulty spikes
- Designing difficulty/flow, reward schedules, or progression
- Diagnosing player complaints: "my choices don't matter", "it's grindy", "that death was cheap", "I'm overwhelmed"
Scope
This is the spine. Sibling skills specialize it and link back here:
- Spatial reward cadence & exploration pull →
open-world-design - Perceptual uniqueness / the oatmeal problem →
procedural-generation,procgen-review - Telegraphing & fair lethality →
combat-design,permadeath-and-lethality - Loot dominance & economy balance →
rpg-systems - Real vs. fake branching →
narrative-and-quest-design
How the pieces fit
GUIDE.md— the cited why: interesting decisions, flow & difficulty, motivation (SDT), feedback & agency, choice architecture. Each principle carries exemplars, sources, the named failure mode, and the procedural/headless implication.CHECKLIST.md— Do/Don't + machine-checkable Test-for criteria, grouped by topic. These are written to be enforced as automated invariants in a generation loop, not just read.
The one idea to anchor on
A game is a series of interesting decisions (Sid Meier). A decision is interesting only when it has believed, persistent consequences, is made with enough information, carries a real trade-off, and has no dominant option. The single highest-leverage audit you can run: scan every system for a strictly-best strategy and delete it.
Why this matters doubly for a generator: a human team has a "this feels off" reflex that catches a broken economy or a cheap death late. An autonomous agent has none. So treat each principle here as an enforced automated invariant, not advice.
What ships with it
2 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.
- 12d ago First seen · 38 lines · 156 tokens per session scan A d53f3ffd7762
game-design-fundamentals is a skill published in the GitHub repository rondorkerin/gamestack (28 stars, last pushed 2mo ago), licensed MIT. It adds 156 tokens to every session and 634 once invoked, about $0.0008 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 2026-08-30.
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