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 bcastelino/agent-skills-kit --skill game-developmentgit clone --depth 1 https://github.com/bcastelino/agent-skills-kitWrote 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/bcastelino/agent-skills-kit/game-development)<a href="https://agentmods.dev/skills/bcastelino/agent-skills-kit/game-development"><img src="https://agentmods.dev/badge/skills/bcastelino/agent-skills-kit/game-development/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/bcastelino/agent-skills-kit/game-development"><img src="https://agentmods.dev/badge/skills/bcastelino/agent-skills-kit/game-development.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 | $0.00027 | $0.01145 |
| Opus 5 | $0.00014 | $0.00573 |
| Sonnet 5 | $0.00005 | $0.00229 |
| Haiku 4.5 | $0.00003 | $0.00114 |
Grade A, and why
game-development 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 8d 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.
This is a copy
91% identical to game-development — 5 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 167 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Game Development
Orchestrator skill that provides core principles and routes to specialized sub-skills.
When to Use This Skill
You are working on a game development project. This skill teaches the PRINCIPLES of game development and directs you to the right sub-skill based on context.
Sub-Skill Routing
Platform Selection
| If the game targets... | Use Sub-Skill |
|---|---|
| Web browsers (HTML5, WebGL) | game-development/web-games |
| Mobile (iOS, Android) | game-development/mobile-games |
| PC (Steam, Desktop) | game-development/pc-games |
| VR/AR headsets | game-development/vr-ar |
Dimension Selection
| If the game is... | Use Sub-Skill |
|---|---|
| 2D (sprites, tilemaps) | game-development/2d-games |
| 3D (meshes, shaders) | game-development/3d-games |
Specialty Areas
| If you need... | Use Sub-Skill |
|---|---|
| GDD, balancing, player psychology | game-development/game-design |
| Multiplayer, networking | game-development/multiplayer |
| Visual style, asset pipeline, animation | game-development/game-art |
| Sound design, music, adaptive audio | game-development/game-audio |
Core Principles (All Platforms)
1. The Game Loop
Every game, regardless of platform, follows this pattern:
INPUT → Read player actions
UPDATE → Process game logic (fixed timestep)
RENDER → Draw the frame (interpolated)
Fixed Timestep Rule:
- Physics/logic: Fixed rate (e.g., 50Hz)
- Rendering: As fast as possible
- Interpolate between states for smooth visuals
2. Pattern Selection Matrix
| Pattern | Use When | Example |
|---|---|---|
| State Machine | 3-5 discrete states | Player: Idle→Walk→Jump |
| Object Pooling | Frequent spawn/destroy | Bullets, particles |
| Observer/Events | Cross-system communication | Health→UI updates |
| ECS | Thousands of similar entities | RTS units, particles |
| Command | Undo, replay, networking | Input recording |
| Behavior Tree | Complex AI decisions | Enemy AI |
What ships with it
10 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.
- 8d ago First seen · 167 lines · 27 tokens per session scan A 45bd375db359
game-development is a skill published in the GitHub repository bcastelino/agent-skills-kit (2 stars, last pushed 1mo ago), licensed MIT. It adds 27 tokens to every session and 1,145 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to game-development, differing in 5 lines, and is treated as a copy.
Other skills, from other repositories
steam-publish
Publish or update a game on Steam with Steamworks and SteamPipe: configure depots and packages, upload builds with steamcmd, set a build live on a branch, and run the release checklists. Use for Steam publishing, appbuild.vdf/steamcmd uploads, depots, beta branches, or a store page release.
ai-behavior-trees-utility-ai
Build a production behavior-tree runtime (Blackboard, action/condition leaves, sequence/selector/parallel composites, decorators) and a Utility AI system (response curves — linear, exponential, sigmoid, quadratic — considerations, and action evaluators), plus hybrid BT-drives-Utility agents. Use when implementing a…
audio-design
Implement game audio practice — bus/mixer architecture and gain in decibels, ducking (sidechain), adaptive/dynamic music via layering and re-sequencing, SFX variation, and beat synchronization. Engine-neutral. Use when the user mentions audio mixing, audio buses, adaptive/dynamic music, ducking, SFX variation, music…
create-game-assets
Plan, generate, source, normalize, and validate cohesive visual game assets. Use for art direction, style bibles, sprites, tilesets, backgrounds, UI art, icons, textures, concept art, or 3D asset briefs.
procedural-gen
Generate game content procedurally — seeded deterministic RNG, value/Perlin/ Simplex noise for terrain and heightmaps, grid dungeon generation (rooms + corridors, BSP, random walk), and weighted loot/drop tables. Engine-neutral algorithms. Use when the user mentions procedural generation, perlin/simplex noise, random…
save-systems
Design save/load for game state — choosing what to serialize, file formats, save slots, atomic crash-safe writes, schema versioning and migration, and autosave. Engine-neutral. Use when the user mentions save system, save/load, game state persistence, save slots, autosave, save file corruption, or migrating old saves…