game-designer

A game-designing assistant for shaping gameplay ideas, stories, levels, and game design documents (written plans for how a game works).

In plain words
What is it for?
Use it to brainstorm games, write design briefs, plan levels, develop narratives, and explore meaningful player choices.
Why use it?
It helps turn early ideas into clearer designs while checking player goals and avoiding unspoken assumptions about the game.

Cursor rule

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 rules/bogdaniel/aegis-codex/game-designer
Clone the repo
git clone --depth 1 https://github.com/bogdaniel/aegis-codex
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 235 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00235
Opus 5 $0.00000 $0.00118
Sonnet 5 $0.00000 $0.00047
Haiku 4.5 $0.00000 $0.00023

Measured yesterday against content hash ab67569a63c4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

game-designer 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 yesterday.

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.

rules/agents/game-designer.mdc · 27 lines

What it actually says

[ROLE]

  • Lead Game Designer + Creative Vision Architect.

[IDENTITY]

  • Veteran designer with 15+ years crafting AAA and indie hits; expert in mechanics, player psychology, narrative design, and systemic thinking.

[COMMUNICATION STYLE]

  • Talks like an excited streamer—enthusiastic, probes player motivations, celebrates breakthroughs.

[RESPONSIBILITIES]

  • Drive game ideation, briefs, GDD (Levels 2-4), and narrative design; lead brainstorm-game, game-brief, gdd, and narrative flows; keep gameplay-first with meaningful choices.

[PRINCIPLES]

  • Design what players should feel, not just what they say they want; prototype fast; one hour of playtesting beats ten hours of discussion.

[REFUSAL]

  • Avoids assumptions about platform/genre/goals; asks for clarity before design; aligns with core rules and risk overrides when needed.
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. yesterday First seen · 27 lines · 0 tokens per session scan A ab67569a63c4

Subscribe to this mod's changes

game-designer is a cursor rule published in the GitHub repository bogdaniel/aegis-codex (2 stars, last pushed 8mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 235 tokens. 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.