What is building-games?

A guide for building playable browser games and interactive 2D or 3D experiences with React and a canvas. It covers the game world, timing, controls, collisions, assets, audio, saving, and game feel.

Use it to build single-player games, games with computer-controlled opponents, simulations, WebGL scenes, and small peer-to-peer multiplayer games.

It helps ensure a game works as an interactive program rather than only looking like a static screen, while keeping movement and game rules consistent.

building-games — Skill for Claude Code by ourobx/agent-ebpf

Install

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.

Any agent

npx skills add ourobx/agent-ebpf --skill building-games

Clone the repo

git clone --depth 1 https://github.com/ourobx/agent-ebpf

Made for: Claude Code.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/ourobx/agent-ebpf/building-games/github.svg)](https://agentmods.dev/skills/ourobx/agent-ebpf/building-games)

Your own site

<a href="https://agentmods.dev/skills/ourobx/agent-ebpf/building-games"><img src="https://agentmods.dev/badge/skills/ourobx/agent-ebpf/building-games/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/ourobx/agent-ebpf/building-games"><img src="https://agentmods.dev/badge/skills/ourobx/agent-ebpf/building-games.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 168 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,314 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00168	$0.03314
Opus 5.5	$0.00067	$0.01326
Sonnet 5.5	$0.00034	$0.00663
Haiku 4.5	$0.00017	$0.00331

Measured 1mo ago against content hash 429fd21e7058, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

building-games 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.

v2/.grok/skills/building-games/SKILL.md · 214 lines

How it starts

The opening of the file, as written. The whole thing — 214 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building Games

Build a playable, correct browser game — not a static screenshot. A game is just a React route with a <canvas> (or <Canvas> for R3F) plus DOM overlay UI. Style the overlay (start screen, HUD, menus) with the design-ui skill; this skill owns the gameplay loop and world.

Controls / inverted A/D: open .grok/skills/controls/SKILL.md before writing WASD, steering, or flight input. Vehicle/flight demos often ship with A/D flipped if you only read this file or a single genre playbook.

Scope note — single-player, bots, or small P2P co-op:

Ship single-player or single-player + AI/bots by default.
2–8 player co-op / casual realtime (shared cursors, party games, casual action among friends) is supported — use the multiplayer-p2p skill (WebRTC mesh, signaled at /api/rtc). Read its trust model first.
P2P is the only supported multiplayer right now. Do not half-build sockets that can’t connect.

References (load on demand):

controls skill (../controls/) — required for movement/steer/flight: player-visible A/D, inverted-steer anti-pattern, flight ailerons, mandatory self-test + window.__controlsTest. Not optional for vehicles/planes.
references/threejs-foundational.md — the deep 3D/loop/perf reference. Read for 3D.
references/3d-libs.md — three.js + @react-three/fiber + drei + rapier usage.
threejs skill (../threejs/) — official full Three.js + TSL API dump (llms-full.txt). Load for advanced materials/shaders/WebGPU/loaders; not for simple 2D canvas games.
references/babylon.md — Babylon.js, the batteries-included 3D engine alternative.
references/phaser.md — Phaser 3, the default engine for 2D games.
references/ecs-architecture.md — entity-component-system structure for larger games.
references/genres/*.md — per-genre playbooks (fps, platformer-2d, racing-kart, puzzle-match3-tetris, voxel-minecraft, endless-runner, topdown-twin-stick, tower-defense, board-card-chess). Genre files do not replace controls.
references/game-feel-juice.md, input.md, audio.md, collision-physics.md, save-persistence.md, procedural-generation.md, ai-pathfinding.md.
game-asset-core (+ game-animation-frames / game-tilesets / game-character-consistency / game-ui-icons) — engine-ready 2D art defaults and verification when generating sprites, sheets, tiles, or UI (see §6).

Pick the specific genre/topic reference for the build; this file is the universal core for loop/world. Input signs → controls. 2D game art → game-asset-core.

Read the full file on GitHub · 214 lines

Files

What ships with it

21 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.

Changes

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 · 214 lines · 168 tokens per session scan A 429fd21e7058

Subscribe to this mod's changes

building-games is a skill published in the GitHub repository ourobx/agent-ebpf (1 stars, last pushed 1mo ago), licensed MIT. It adds 168 tokens to every session and 3,314 once invoked, about $0.0007 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 2026-09-04.

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building-games