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 buildfastwithai/gen-ai-experiments --skill html-game-generatorgit clone --depth 1 https://github.com/buildfastwithai/gen-ai-experimentsWrote 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/buildfastwithai/gen-ai-experiments/html-game-generator)<a href="https://agentmods.dev/skills/buildfastwithai/gen-ai-experiments/html-game-generator"><img src="https://agentmods.dev/badge/skills/buildfastwithai/gen-ai-experiments/html-game-generator/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/buildfastwithai/gen-ai-experiments/html-game-generator"><img src="https://agentmods.dev/badge/skills/buildfastwithai/gen-ai-experiments/html-game-generator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high System Prompt Leakage · line 38 Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.Fix: Remove any instructions that reveal, print, or output system prompts or internal rules. System instructions should never be exposed to end users.
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 | $0.00195 | $0.07529 |
| Opus 5.5 | $0.00078 | $0.03012 |
| Sonnet 5.5 | $0.00039 | $0.01506 |
| Haiku 4.5 | $0.00019 | $0.00753 |
Grade A, and why
html-game-generator 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 — 342 lines — stays where its author put it; the contents beside it link to each section on GitHub.
HTML Game Generator
Turn a game idea into one HTML file the user can double-click and play — finished, not prototyped.
Purpose
The deliverable is a complete game: title screen, tutorial or control hints, core loop, difficulty progression, win/lose states, sound, particles, persistence, and a restart path. It runs offline from the filesystem with zero setup, zero build step, zero network requests, and zero dependencies.
The failure mode worth naming up front is the tech demo: a grey rectangle that moves, one enemy, no menu, no sound, // TODO: add more levels. That is not the deliverable. A user who asks for a tower defense game wants to play tower defense for twenty minutes, not to see that tower defense is possible. Every choice in this skill points at that difference.
The second failure mode is scope collapse under pressure — quietly dropping the third enemy type or the upgrade shop because the file was getting long. Length is not the constraint. If something has to give, simplify how things look, never what the player can do.
Capabilities
Determine which systems the game needs and build them. The request rarely names them; infer from the genre and the described experience.
- Physics — AABB and swept collision, gravity and drag, impulse resolution, verlet ropes/soft bodies, projectile ballistics, restitution and friction.
- AI — finite state machines, steering behaviours (seek/flee/wander/separate), flocking, aggro and threat, difficulty curves, opponent decks and build orders, utility scoring.
- Pathfinding — A* on grids, flow fields for many units, line-of-sight and simple navmesh, local avoidance.
- Procedural generation — value noise, cellular automata caves, room-and-corridor dungeons, wave-function-collapse-style tiling, weighted loot and encounter tables, seeded RNG for reproducibility.
- Combat — hitboxes/hurtboxes, i-frames, damage types and resistances, knockback, status effects, cooldowns, crits.
- Economy and progression — currencies, costs and rewards, XP curves, upgrade trees, unlocks, prestige loops.
- Inventory and crafting — grid or list inventories, stacking, equipment slots, recipes, containers.
- Rendering — Canvas 2D, layered canvases, camera with follow/lerp/shake, parallax, tilemaps with culling, procedural sprite generation, lighting and fog of war, DOM/CSS for UI.
- Particles and effects — pooled emitters, screen shake, hit-stop, flashes, trails, weather.
- Audio — full Web Audio synthesis: SFX, adaptive music, mixing, ducking.
- UI — menus, HUD, modals, tooltips, drag-and-drop, minimaps, tech trees, settings, pause.
- Animation — tweening with easing, sprite and skeletal-style animation, state-driven transitions.
- Persistence — LocalStorage saves with versioning and migration, autosave, settings, high scores.
What ships with it
4 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 · 342 lines · 195 tokens per session scan A 1092ad348a91
html-game-generator is a skill published in the GitHub repository buildfastwithai/gen-ai-experiments (789 stars, last pushed 1mo ago), licensed MIT. It adds 195 tokens to every session and 7,529 once invoked, about $0.0008 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 2026-08-30.
Other skills, from other repositories
playtest-report
Structured playtest report template, or turn existing playtest notes into structured feedback.
godot-signals-groups
Build event-driven, decoupled Godot 4.7 gameplay with signals and node groups: declare and emit custom signals, connect with Callables (incl. bind/one-shot), and broadcast to many nodes via groups and callgroup. Use when wiring node communication in a Godot project, replacing tight references with signals…
motion
Reconstruct a skeleton from calibrated mesh projections and sequential VLM joint annotations, then fit joints and skin weights. Generate motion from joint-position trajectories, rhythm and contact constraints through IK; refine bone orientation against the action, then export, retarget and validate on the target mesh.
unity-addressables
Manage Addressables groups, entries, profiles and content builds (com.unity.addressables, reflection-based).
unity-manual-component
Manually add, configure, reorder, and copy components on GameObjects using Unity Editor UI. For one-off Inspector workflows that do not need REST automation.
threejs-exposure-color-grading
Build a measured exposure and grading path in Three.js. Use for a 64x36 encoded luminance meter, asynchronous readback, weighted log-average exposure, asymmetric adaptation, single tone-map ownership, and a generated 32-cube post-tone-map LUT.