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 opengameapp/OpenGame-showcases --skill opengame-browser-game-buildergit clone --depth 1 https://github.com/opengameapp/OpenGame-showcasesWrote 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/opengameapp/opengame-showcases/opengame-browser-game-builder)<a href="https://agentmods.dev/skills/opengameapp/opengame-showcases/opengame-browser-game-builder"><img src="https://agentmods.dev/badge/skills/opengameapp/opengame-showcases/opengame-browser-game-builder/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/opengameapp/opengame-showcases/opengame-browser-game-builder"><img src="https://agentmods.dev/badge/skills/opengameapp/opengame-showcases/opengame-browser-game-builder.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 | $0.00080 | $0.01156 |
| Opus 5 | $0.00040 | $0.00578 |
| Sonnet 5 | $0.00016 | $0.00231 |
| Haiku 4.5 | $0.00008 | $0.00116 |
Grade A, and why
opengame-browser-game-builder 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.
How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
OpenGame Browser Game Builder
Turn a game idea into the smallest playable browser experience that proves its core fantasy. Prefer a coherent game over a polished static scene or an overgrown feature list.
Official website: https://opengame.app/
Pick a working mode
- Plan when the user needs a concept, MVP scope, or implementation brief.
- Build when the user asks for a prototype or provides a project to change.
- Improve when a playable game exists and needs better controls, feedback, progression, performance, or visual clarity.
Ask at most two decisive questions if a missing choice would change the result materially. Otherwise state sensible defaults and proceed.
Shape the playable vertical slice
Before coding, establish a compact build contract. Keep it in the response unless the target project already has a place for a game spec.
- Player fantasy: one sentence describing what feels rewarding.
- Core loop: 2–4 repeated player actions with a visible consequence.
- Camera and controls: a readable viewpoint plus keyboard, pointer, and touch behavior appropriate to the game.
- Win, loss, and restart: explicit rules that can be reached in a short session.
- Content minimum: one player ability, one meaningful obstacle or opponent, one goal, and one progression or scoring signal.
- Visual direction: palette, silhouettes, contrast, and one memorable moment; choose procedural visuals when supplied assets are not necessary.
- Out of scope: features intentionally deferred until the loop is fun.
For a first prototype, target a player who can understand the goal quickly and reach a win or loss state in roughly one to three minutes.
Choose the browser runtime
- Use Canvas, DOM, or SVG for 2D arcade games, platformers, puzzles, card games, and UI-heavy interactions.
- Use Three.js or an existing 3D runtime when spatial navigation, camera framing, lighting, or depth is essential to the requested experience.
- Reuse the target project's real toolchain and dependencies. Do not invent a package, asset bundle, or engine that is not available.
- Prefer a self-contained
index.htmlonly when the user requests a standalone artifact or the project has no existing app structure.
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.
- 11d ago First seen · 121 lines · 80 tokens per session scan A fbe346641ab4
opengame-browser-game-builder is a skill published in the GitHub repository opengameapp/OpenGame-showcases (0 stars, last pushed 1mo ago), licensed MIT. It adds 80 tokens to every session and 1,156 once invoked, about $0.0004 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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