beat CLAUDE.md

A Claude Code plugin for Behavior-Driven Development, or BDD, where Gherkin feature files describe the expected behavior and act as the main specification.

In plain words
What is it for?
Creating behavior specifications and following a workflow based on feature files through the plugin's available skills.
Why use it?
It gives coding work a shared, readable description of what the software should do before implementation and testing.

Instructions file

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.

agentmods
npx agentmods add instructions/kirkchen/beat/claude-md
Clone the repo
git clone --depth 1 https://github.com/kirkchen/beat
Per session 3,899 This file is loaded in full into every session.
When invoked 3,899 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
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 $0.03899 $0.03899
Opus 5 $0.01950 $0.01950
Sonnet 5 $0.00780 $0.00780
Haiku 4.5 $0.00390 $0.00390

Measured 2d ago against content hash c4ab35fce1fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 2d 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.

CLAUDE.md · 248 lines

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

Read the full file on GitHub · 248 lines

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. 2d ago First seen · 248 lines · 3,899 tokens per session scan A c4ab35fce1fa

Subscribe to this mod's changes

beat CLAUDE.md is an instructions file published in the GitHub repository kirkchen/beat (7 stars, last pushed 2mo ago), licensed MIT. It adds 3,899 tokens to every session, about $0.0195 per session on Opus 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.

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