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tiny-world-builder: Skill for Claude Code

.agents/skills/fractal/SKILL.md

fractal is a skill for Claude Code, Codex from jasonkneen/tiny-world-builder. It costs 149 tokens per session (1,538 once invoked), scanned B, original, AGPL-3.0.

A command-line way to delegate analysis-heavy work to Fractal, an agent that repeatedly reasons through large amounts of information. It is designed for tasks that require combining evidence from many files.

In plain words
What is it for?
Use it to audit a large project, synthesize findings across files, investigate complex behavior, or produce an analysis from a broad codebase review.
Why use it?
It helps handle deep codebase analysis when a short inspection would miss important relationships or context.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: installed under .agents/ (shared by several agents).

This is jasonkneen/tiny-world-builder's own configuration. It tells Claude Code and Codex how to work on tiny-world-builder itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything tiny-world-builder configures →

not rated 1.6krepo +4 yesterday B scan 149 tokens AGPL-3.0
View source ↗ jasonkneen/tiny-world-builder tinyworld.build
About the project

Tiny World Builder is a browser-based 3D voxel editor for creating, sculpting, exploring, saving, remixing, exporting, and sharing small block-based worlds. It is used by people who want to build terrain and scenes with objects such as homes, paths, crops, and animals. Its catalogue add-ons support work with the editor.

jasonkneen/tiny-world-builder · 1,621 stars · on GitHub · tinyworld.build

Reuse

Borrowing it

Nothing to install: this file belongs to jasonkneen/tiny-world-builder. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/jasonkneen/tiny-world-builder/main/.agents/skills/fractal/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/jasonkneen/tiny-world-builder

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 fractal

README.md
[![agentmods](https://agentmods.dev/badge/skills/jasonkneen/tiny-world-builder/fractal/github.svg)](https://agentmods.dev/skills/jasonkneen/tiny-world-builder/fractal)
Your own site
<a href="https://agentmods.dev/skills/jasonkneen/tiny-world-builder/fractal"><img src="https://agentmods.dev/badge/skills/jasonkneen/tiny-world-builder/fractal/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 fractal

Your own site · 80×15
<a href="https://agentmods.dev/skills/jasonkneen/tiny-world-builder/fractal"><img src="https://agentmods.dev/badge/skills/jasonkneen/tiny-world-builder/fractal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 149 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,538 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00149 $0.01538
Opus 5.5 $0.00060 $0.00615
Sonnet 5.5 $0.00030 $0.00308
Haiku 4.5 $0.00015 $0.00154

Measured 2mo ago against content hash d64b291362cb, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

fractal scanned grade B with 2 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 2mo 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.

Downloads and executes remote codemediumSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

|| curl -LsSf https://fractal.trampoline.ai/install.sh | sh

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

|| curl -LsSf https://fractal.trampoline.ai/install.sh | sh
.agents/skills/fractal/SKILL.md · 104 lines

The source is not reproduced here

Licensed AGPL-3.0

The repository is licensed AGPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

Files

What ships with it

1 file 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.

  1. 2mo ago First seen · 104 lines · 149 tokens per session scan B d64b291362cb

Subscribe to this mod's changes

fractal is a skill published in the GitHub repository jasonkneen/tiny-world-builder (1,621 stars, last pushed yesterday), licensed AGPL-3.0. It adds 149 tokens to every session and 1,538 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it B with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Building agentsbuildminecraftvoxel
Related

fractal compared with skills from other repositories

fractal next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
fractaljasonkneen/tiny-world-builderSkill1.6kyesterdayAGPL-3.0B149Claude Code, Codex
minecraft-modpack-serverNousResearch/hermes-agentSkill261kyesterdayMITB19Claude Code, Codex
gamedev-shippingericrisco/rsc-harnessSkill5032d agoMITA99Claude Code, Codex
build-and-compilevstorm-co/pydantic-deepagentsSkill1.1k7d agoMITA15Claude Code, Codex
huawei-cloud-codearts-pipeline-diagnosehuaweicloud/huaweicloud-skillsSkill59todayMITA273Claude Code, Codex
verifying-compose-uirnett/gradle-mcpSkill68yesterdayApache-2.0A40Claude Code, Codex
rag-and-memoryDevelopersGlobal/ai-agent-skillsSkill2169d agoMITA36Claude Code, Codex