Borrowing it
Nothing to install: this file belongs to nicepkg/agent-world. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/nicepkg/agent-world/main/CLAUDE.mdgit clone --depth 1 https://github.com/nicepkg/agent-worldWrote 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.
[](https://agentmods.dev/instructions/nicepkg/agent-world/claude-md)<a href="https://agentmods.dev/instructions/nicepkg/agent-world/claude-md"><img src="https://agentmods.dev/badge/instructions/nicepkg/agent-world/claude-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.
<a href="https://agentmods.dev/instructions/nicepkg/agent-world/claude-md"><img src="https://agentmods.dev/badge/instructions/nicepkg/agent-world/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.03291 | $0.03291 |
| Opus 5.5 | $0.01316 | $0.01316 |
| Sonnet 5.5 | $0.00658 | $0.00658 |
| Haiku 4.5 | $0.00329 | $0.00329 |
Grade A, and why
agent-world CLAUDE.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.
How it starts
The opening of the file, as written. The whole thing — 262 lines — stays where its author put it; the contents beside it link to each section on GitHub.
AgentWorld — Multi-Agent Simulation Framework
Everything-as-Plugin architecture for multi-agent simulation. Change the config, run a completely different world.
User Profile
- Name: Jinming Yang
- Role: nicepkg open source org founder, framework author
- Goal: Build a mind-blowing AI multi-agent simulation open source project + Bilibili videos
- Style: Rapid iteration — get it working first, then optimize
- Tech Background: TypeScript full-stack, frontend origin
Communication & Language
- Chinese for communication, English for code, comments, docs, and technical terms
- Be specific and actionable — no vague advice
- Show code examples, not just descriptions
- No backward compatibility needed — the project is NOT open-sourced yet. Delete old code directly, never deprecate.
Project Structure
agent-world/
├── CLAUDE.md # This file (system prompt for Claude)
├── package.json # pnpm monorepo root (turbo + vitest + husky)
├── pnpm-workspace.yaml # Workspace config + dependency catalog
├── turbo.json # Turbo task pipeline
├── vitest.config.ts # Root-level vitest config
├── eslint.config.mjs # ESLint flat config (v10)
├── commitlint.config.js # Conventional commits
├── packages/
│ ├── core/ # @agent-world/core — Engine, EventBus, Plugin system
│ ├── brain-llm/ # @agent-world/brain-llm — LLM brain (via Vercel AI SDK)
│ ├── memory/ # @agent-world/memory — Memory plugins (Simple + Tiered)
│ ├── world/ # @agent-world/world — World plugins (Grid, Abstract)
│ ├── renderer-server/ # @agent-world/renderer-server — WebSocket renderer (server)
│ ├── renderer-client/ # @agent-world/renderer-client — WebSocket client (browser, zero-dep)
│ └── ui/ # @agent-world/ui — React hooks, components, primitives, providers, server utils
├── examples/
│ ├── hello-world/ # Minimal 5-agent grid demo
│ ├── spring-autumn/ # AI Spring & Autumn Period — 7 kingdoms scenario
│ └── template/ # Copy-this-to-start experiment scaffold
├── docs/ # Agent output directories + design docs
└── .claude/
├── agents/ # 10 expert agent personas
└── skills/ # Skill definitions
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.
- 2mo ago First seen · 262 lines · 3,291 tokens per session scan A 31ccdc5bfa0c
agent-world CLAUDE.md is an instructions file published in the GitHub repository nicepkg/agent-world (6 stars, last pushed 8mo ago), licensed MIT. It adds 3,291 tokens to every session, about $0.0132 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 2026-08-31.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deno copilot-instructions.md
Copilot instructions for denoland/deno, covering deno development guide for github copilot, network access, high level overview, key directories and key files to understand first.