core-loop-design

core-loop-design is a skill for Claude Code from MRCalderon3D/everything-game-dev-code. It costs 23 tokens per session (417 once invoked), scanned A, original, MIT.

A game design guide for defining what players repeatedly do, why it is enjoyable, and how progression and supporting activities connect to it.

In plain words
What is it for?
It is for mapping player actions, feedback, rewards, failure points, session length, and tutorial needs before building a playable test version.
Why use it?
It helps when a game feels unfocused or when new systems risk distracting from its main activity.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the everything-game-dev-code plugin — 74 skills, 67 commands, 42 agents, 3 hooks, 6 MCP servers shipped together

Good fit It is for mapping player actions, feedback, rewards, failure points, session length, and tutorial needs before building a playable test version.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mrcalderon3d/everything-game-dev-code/core-loop-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 MRCalderon3D/everything-game-dev-code --skill core-loop-design
Clone the repo
git clone --depth 1 https://github.com/MRCalderon3D/everything-game-dev-code

Made for: Claude Code.

Or install everything-game-dev-code, the plugin that ships this one along with the rest of its 74 skills, 67 commands, 42 agents, 3 hooks, 6 MCP servers.

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 core-loop-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/mrcalderon3d/everything-game-dev-code/core-loop-design/github.svg)](https://agentmods.dev/skills/mrcalderon3d/everything-game-dev-code/core-loop-design)
Your own site
<a href="https://agentmods.dev/skills/mrcalderon3d/everything-game-dev-code/core-loop-design"><img src="https://agentmods.dev/badge/skills/mrcalderon3d/everything-game-dev-code/core-loop-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 core-loop-design

Your own site · 80×15
<a href="https://agentmods.dev/skills/mrcalderon3d/everything-game-dev-code/core-loop-design"><img src="https://agentmods.dev/badge/skills/mrcalderon3d/everything-game-dev-code/core-loop-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 417 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00023 $0.00417
Opus 5.5 $0.00009 $0.00167
Sonnet 5.5 $0.00005 $0.00083
Haiku 4.5 $0.00002 $0.00042

Measured 1mo ago against content hash 0520b2730cde, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

core-loop-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.

skills/design/core-loop-design/SKILL.md · 62 lines

What it actually says

Core Loop Design

Purpose

Define the primary player activity loop and the support loops that sustain mastery, variety, and progression.

Use When

  • a concept needs gameplay structure
  • the current loop feels unfocused
  • new systems risk diluting the core fantasy

Inputs

  • product pillars
  • target audience
  • competitive references
  • session and progression goals

Process

  1. state what the player repeatedly does and why it is satisfying
  2. map supporting loops that reinforce the core loop
  3. identify inputs, feedback, rewards, and failure points
  4. test whether the loop fits the intended session length and mastery curve
  5. cut systems that do not serve the loop

Outputs

  • core loop definition
  • support loop map
  • design constraints
  • candidate tutorial beats

Quality Bar

  • the loop is expressible as a closed cycle of player actions, rewards, and re-entry motivation
  • each loop step names the player verb, the feedback, and a duration target
  • supporting loops (session, progression, economy) are explicitly connected to the core loop
  • the loop is testable in a gray-box build without final art

Common Failure Modes

  • loops that depend on content volume instead of repeatable mechanics
  • reward steps without a defined re-entry hook back into the loop
  • a core loop tuned only on paper, never validated in a playable slice
  • conflating the core loop with the meta progression that wraps it
  • systems-designer
  • gdd-designer
  • level-designer
  • gdd
  • plan
  • onboarding

Notes

  • Keep this skill aligned with the relevant rules layer and current project documentation.
  • If engine-specific constraints materially change the workflow, hand off to the matching engine skill or engine-specific reviewer.
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 · 62 lines · 23 tokens per session scan A 0520b2730cde

Subscribe to this mod's changes

core-loop-design is a skill published in the GitHub repository MRCalderon3D/everything-game-dev-code (96 stars, last pushed 11d ago), licensed MIT. It adds 23 tokens to every session and 417 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 2026-09-03.

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