game-design

Guidance for designing how a game plays, including its repeating gameplay cycle, written design plan, player motivations, rewards, and progression.

In plain words
What is it for?
Useful for defining the short action-feedback-reward cycle, documenting mechanics and advancement in a game design document, and planning for different player motivations.
Why use it?
It helps turn a game idea into understandable systems that can be tested and developed in a manageable order.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/diillson/chatcli/game-design
Any agent
npx skills add diillson/chatcli --skill game-design
Clone the repo
git clone --depth 1 https://github.com/diillson/chatcli

Made for: Claude Code, Codex.

Per session 18 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 639 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00018 $0.00639
Opus 5 $0.00009 $0.00319
Sonnet 5 $0.00004 $0.00128
Haiku 4.5 $0.00002 $0.00064

Measured 3d ago against content hash 93c417904682, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 3d 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.

Origin

This is a copy

100% identical to game-design — 0 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.

.agent/skills/game-development/game-design/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Game Design Principles

Design thinking for engaging games.


1. Core Loop Design

The 30-Second Test

Every game needs a fun 30-second loop:
1. ACTION → Player does something
2. FEEDBACK → Game responds
3. REWARD → Player feels good
4. REPEAT

Loop Examples

Genre Core Loop
Platformer Run → Jump → Land → Collect
Shooter Aim → Shoot → Kill → Loot
Puzzle Observe → Think → Solve → Advance
RPG Explore → Fight → Level → Gear

2. Game Design Document (GDD)

Essential Sections

Section Content
Pitch One-sentence description
Core Loop 30-second gameplay
Mechanics How systems work
Progression How player advances
Art Style Visual direction
Audio Sound direction

Principles

  • Keep it living (update regularly)
  • Visuals help communicate
  • Less is more (start small)

3. Player Psychology

Motivation Types

Type Driven By
Achiever Goals, completion
Explorer Discovery, secrets
Socializer Interaction, community
Killer Competition, dominance

Reward Schedules

Schedule Effect Use
Fixed Predictable Milestone rewards
Variable Addictive Loot drops
Ratio Effort-based Grind games

4. Difficulty Balancing

Flow State

Too Hard → Frustration → Quit
Too Easy → Boredom → Quit
Just Right → Flow → Engagement

Balancing Strategies

Strategy How
Dynamic Adjust to player skill
Selection Let player choose
Accessibility Options for all

5. Progression Design

Progression Types

Type Example
Skill Player gets better
Power Character gets stronger
Content New areas unlock
Story Narrative advances

Pacing Principles

Read the full file on GitHub · 130 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. 3d ago First seen · 130 lines · 18 tokens per session scan A 93c417904682

Subscribe to this mod's changes

game-design is a skill published in the GitHub repository diillson/chatcli (89 stars, last pushed 4d ago), licensed Apache-2.0. It adds 18 tokens to every session and 639 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to game-design, differing in 0 lines, and is treated as a copy.