AG Kit is a toolkit that gives Google Antigravity coding agents a structured workspace with rules, skills, specialist agents, workflows, persistent memory, orchestration, MCP guidance, and a safety hook. It is for building and operating agent workflows in Antigravity, and its catalogue entries provide parts of that workspace contract.
Borrowing it
Nothing to install: this file belongs to vudovn/ag-kit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/vudovn/ag-kit/main/.agents/skills/game-development/SKILL.mdgit clone --depth 1 https://github.com/vudovn/ag-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/vudovn/ag-kit/game-development)<a href="https://agentmods.dev/skills/vudovn/ag-kit/game-development"><img src="https://agentmods.dev/badge/skills/vudovn/ag-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/vudovn/ag-kit/game-development"><img src="https://agentmods.dev/badge/skills/vudovn/ag-kit/game-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00018 | $0.01191 |
| Opus 5.5 | $0.00007 | $0.00476 |
| Sonnet 5.5 | $0.00004 | $0.00238 |
| Haiku 4.5 | $0.00002 | $0.00119 |
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 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
7 near-identical copies found in the catalogue:
- game-development — 95% identical, 2 lines differ
- game-development — 95% identical, 2 lines differ
- game-development — 95% identical, 2 lines differ
- game-development — 95% identical, 2 lines differ
- game-development — 95% identical, 2 lines differ
- game-development — 94% identical, 3 lines differ
- game-development — 91% identical, 5 lines differ
How it starts
The opening of the file, as written. The whole thing — 170 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.
- 1mo ago First seen · 170 lines · 18 tokens per session scan A a6f0f9e1b4ee
game-development is a skill published in the GitHub repository vudovn/ag-kit (8,199 stars, last pushed 2d ago), licensed MIT. It adds 18 tokens to every session and 1,191 once invoked, about $0.0001 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.