tiny-world-builder: Instructions file for Codex

AGENTS.md

tiny-world-builder AGENTS.md is an instructions file for Codex, OpenCode from jasonkneen/tiny-world-builder. It costs 2,585 tokens per session, scanned A, original, AGPL-3.0.

Project instructions for an AI coding agent working on the tiny-world-builder repository. They describe the project structure, local skills, coding style, and the role of an AGENTS.md file.

In plain words
What is it for?
Use them when an AI agent is inspecting, changing, or extending the tiny-world-builder codebase and needs its local rules.
Why use it?
They give the agent the repository-specific context needed to make changes consistently. This reduces guesswork about where files belong and how work should be done.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md.

This is jasonkneen/tiny-world-builder's own configuration. It tells Codex and OpenCode 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 →

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.md
Clone the repo
git clone --depth 1 https://github.com/jasonkneen/tiny-world-builder

Made for: Codex, OpenCode.

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 tiny-world-builder AGENTS.md

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

Your own site · 80×15
<a href="https://agentmods.dev/instructions/jasonkneen/tiny-world-builder/agents-md"><img src="https://agentmods.dev/badge/instructions/jasonkneen/tiny-world-builder/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 2,585 This file is loaded in full into every session.
When invoked 2,585 The same file — it is already loaded in full.
Security scan A 0 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 $0.02585 $0.02585
Opus 5.5 $0.01034 $0.01034
Sonnet 5.5 $0.00517 $0.00517
Haiku 4.5 $0.00259 $0.00259

Measured 2mo ago against content hash c3d79447673e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

tiny-world-builder AGENTS.md 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 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.

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.

AGENTS.md · 154 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

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 · 154 lines · 2,585 tokens per session scan A c3d79447673e

Subscribe to this mod's changes

tiny-world-builder AGENTS.md is an instructions file published in the GitHub repository jasonkneen/tiny-world-builder (1,621 stars, last pushed yesterday), licensed AGPL-3.0. It adds 2,585 tokens to every session, about $0.0103 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 2026-08-30.

Related

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deepseek-harness AGENTS.mddeepseek-ai/deepseek-harnessInstructions file274k2d agoMITA4,313Codex, OpenCode