Borrowing it
Nothing to install: this file belongs to kirkchen/beat. 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/kirkchen/beat/main/CLAUDE.mdgit clone --depth 1 https://github.com/kirkchen/beatWrote 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/kirkchen/beat/claude-md)<a href="https://agentmods.dev/instructions/kirkchen/beat/claude-md"><img src="https://agentmods.dev/badge/instructions/kirkchen/beat/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/kirkchen/beat/claude-md"><img src="https://agentmods.dev/badge/instructions/kirkchen/beat/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 | $0.04163 | $0.04163 |
| Opus 5.5 | $0.01665 | $0.01665 |
| Sonnet 5.5 | $0.00833 | $0.00833 |
| Haiku 4.5 | $0.00416 | $0.00416 |
Grade A, and why
beat 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 19d 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 — 248 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
What Is Beat
Beat is a Claude Code plugin that provides an agent-driven BDD (Behavior-Driven Development) workflow. It uses Gherkin .feature files as the single source of truth for behavior specifications. Beat is not an application — it is a set of skills (SKILL.md files) that Claude Code loads as a plugin.
Installation
claude --plugin-dir /path/to/beat
Architecture
Plugin Structure
beat/
├── .claude-plugin/plugin.json # Claude Code plugin manifest
├── .codex-plugin/plugin.json # Codex plugin manifest (with interface block)
├── .agents/plugins/marketplace.json # Codex marketplace manifest — makes this repo a single-plugin marketplace
├── plugins/beat/ # Codex plugin overlay (symlinks to root files: skills, assets, .codex-plugin, references)
├── assets/ # Brand icons (composerIcon, logo) for Codex
├── skills/ # Each subdirectory = one invocable skill (SKILL.md + synced references/)
│ ├── design/ # /beat:design — create change + generate spec artifacts
│ ├── plan/ # /beat:plan — task breakdown with multi-role review
│ ├── apply/ # /beat:apply — TDD implementation
│ ├── verify/ # /beat:verify — 5-dimension verification
│ ├── archive/ # /beat:archive — sync features + archive completed change
│ ├── explore/ # /beat:explore — thinking partner mode
│ ├── setup/ # /beat:setup — create beat/config.yaml
│ └── distill/ # /beat:distill — reverse-engineer specs from code
├── references/ # Source of truth for shared schemas — edit here, then run scripts/sync-references.mjs
│ ├── status-schema.md # status.yaml format
│ ├── config-schema.md # config.yaml format
│ ├── testing-conventions.md # Annotation format and e2e test style reference
│ ├── context-format.md # beat/CONTEXT.md glossary format (Layer 1 living docs)
│ ├── adr-format.md # docs/adr/ ADR format + three-condition gate (Layer 2 living docs)
│ ├── architecture-format.md # beat/ARCHITECTURE.md hub + module README format (Layer 3 living docs)
│ ├── tool-mapping.md # Cross-platform tool name mapping (root only)
│ └── codex-agents-snippet.md # Per-project AGENTS.md snippet for Codex (root only)
├── scripts/sync-references.mjs # Syncs /references into each skill's references/ (see header for rationale)
├── NOTICE.md # Third-party attribution (mattpocock-skills, superpowers — both MIT)
├── hooks/ # Claude Code hooks (Codex ignores; replaced by AGENTS.md snippet)
│ ├── hooks.json # SessionStart hook config
│ └── session-start # Detects Beat project, injects workflow context
├── tests/ # Automated skill tests (claude -p headless)
│ ├── test-helpers.sh # Shared assertion framework
│ ├── run-all.sh # Run all fast tests (--integration for pipeline)
│ ├── analyze-token-usage.py # Token analysis for test sessions
│ ├── skill-triggering/ # Layer 1: Description CSO validation
│ ├── skill-content/ # Layer 2: Enforcement awareness smoke tests
│ ├── pressure/ # Layer 3: Anti-rationalization under pressure
│ └── pipeline/ # Layer 4: End-to-end pipeline (--integration)
└── README.md
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.
- 19d ago Changed · +111 tokens per session 22453da5824e
- 20d ago Changed · +153 tokens per session 900d9917f3dc
- 1mo ago First seen · 248 lines · 3,899 tokens per session scan A c4ab35fce1fa
beat CLAUDE.md is an instructions file published in the GitHub repository kirkchen/beat (7 stars, last pushed 4d ago), licensed MIT. It adds 4,163 tokens to every session, about $0.0167 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).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.