game-design

game-design is a skill for Claude Code, Codex from phuonghx/aim-cli. It costs 90 tokens per session (829 once invoked), scanned A, original, MIT.

Reference material for designing how a game plays and how players progress through it. It explains the repeating gameplay loop, game design documents, rewards, difficulty, pacing, and common design mistakes.

In plain words
What is it for?
Use it to define the main gameplay cycle, organize a game design document, plan progression, tune difficulty and rewards, and evaluate whether repeated play is enjoyable.
Why use it?
It helps turn a vague game idea into a testable play experience and exposes problems that planning alone may hide.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to define the main gameplay cycle, organize a game design document, plan progression, tune difficulty and rewards, and evaluate whether repeated play is enjoyable.

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Install with agentmods
npx agentmods add skills/phuonghx/aim-cli/game-design
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 phuonghx/aim-cli --skill game-design
Clone the repo
git clone --depth 1 https://github.com/phuonghx/aim-cli

Made for: Claude Code, Codex.

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.

agentmods badge for game-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/phuonghx/aim-cli/game-design/github.svg)](https://agentmods.dev/skills/phuonghx/aim-cli/game-design)
Your own site
<a href="https://agentmods.dev/skills/phuonghx/aim-cli/game-design"><img src="https://agentmods.dev/badge/skills/phuonghx/aim-cli/game-design/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.

agentmods 80×15 button for game-design

Your own site · 80×15
<a href="https://agentmods.dev/skills/phuonghx/aim-cli/game-design"><img src="https://agentmods.dev/badge/skills/phuonghx/aim-cli/game-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 829 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00090 $0.00829
Opus 5.5 $0.00036 $0.00332
Sonnet 5.5 $0.00018 $0.00166
Haiku 4.5 $0.00009 $0.00083

Measured 1mo ago against content hash ff00f6e55614, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

game-design 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.

aim/templates/aim-agents/skills/game-development/game-design/SKILL.md · 113 lines

How it starts

The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Game Design

Decisions about what makes a game fun and how players grow through it. The throughline: prove fun by playing, not by planning.

The Core Loop

The 30-second test

If a game isn't enjoyable in a tight repeating cycle, no amount of content saves it. The cycle:

Act → Get feedback → Earn a reward → Go again.

The player does something, the game answers clearly, that answer feels good, and they immediately want another go.

How it looks per genre

Genre The loop
Platformer Run → jump → land → collect
Shooter Aim → fire → kill → loot
Puzzle Observe → reason → solve → move on
RPG Explore → fight → level up → upgrade gear

The Design Document

Sections worth having

Section Captures
Pitch The whole game in one sentence
Core loop The 30-second gameplay cycle
Mechanics How each system actually works
Progression How the player moves forward
Art style The visual direction
Audio The sound direction

How to treat it

  • Keep it alive — revise it as the game changes; a stale GDD lies.
  • Show, don't just tell — diagrams and reference images communicate faster than paragraphs.
  • Stay small early — scope down first; expand only once the core proves out.

What Drives Players

Motivation archetypes

Player Chasing
Achiever Goals, completion, 100%
Explorer Discovery, hidden corners, secrets
Socializer People, interaction, community
Killer Competition, beating others, dominance

Reward timing

Schedule Feel Where it fits
Fixed Predictable, dependable Milestone payouts
Variable Compelling, hard to put down Loot drops
Ratio (effort-based) Earned through work Grind-oriented systems

Difficulty and Flow

Keep the player in the channel between boredom and panic:

  • Too hard → frustration → they quit.
  • Too easy → boredom → they quit.
  • Tuned right → flow → they stay engaged.

Read the full file on GitHub · 113 lines

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.

  1. 1mo ago First seen · 113 lines · 90 tokens per session scan A ff00f6e55614

Subscribe to this mod's changes

game-design is a skill published in the GitHub repository phuonghx/aim-cli (1 stars, last pushed 3mo ago), licensed MIT. It adds 90 tokens to every session and 829 once invoked, about $0.0004 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 2026-08-31.