Claude Code Harness is a development workflow for coding agents that organizes work into planning, implementation, review, synchronization, and release stages. It helps developers keep specifications, tests, independent reviews, and release evidence connected while using tools such as Claude Code, Codex CLI, Cursor, or Grok.
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.
npx agentmods add instructions/chachamaru127/claude-code-harness/claude-mdgit clone --depth 1 https://github.com/Chachamaru127/claude-code-harnessWrote 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/chachamaru127/claude-code-harness/claude-md)<a href="https://agentmods.dev/instructions/chachamaru127/claude-code-harness/claude-md"><img src="https://agentmods.dev/badge/instructions/chachamaru127/claude-code-harness/claude-md.svg" alt="Measured on agentmods" 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 | $0.04080 | $0.04080 |
| Opus 5 | $0.02040 | $0.02040 |
| Sonnet 5 | $0.00816 | $0.00816 |
| Haiku 4.5 | $0.00408 | $0.00408 |
Grade B, and why
claude-code-harness CLAUDE.md scanned grade B with 1 finding 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
(user scope `~/.claude/settings.json` 等) の permissions 層が担い、ガードレール層は How it starts
The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md - Claude Harness Development Guide
This file provides guidance for Claude Code when working in this repository.
Project Overview
Claude harness is a plugin for autonomous operation of Claude Code in a "Plan → Work → Review" workflow.
Special note: This project is self-referential — it uses the harness itself to improve the harness.
Claude Code Feature Utilization
CC v2.1.111+ と Opus 4.7 の機能を活用。詳細: docs/CLAUDE-feature-table.md 長時間タスクの手順: docs/long-running-harness.md
主要活用機能: Agent Memory, Worktree isolation, Agent hooks, PreCompact/PostCompact, PermissionDenied tracking, 1M Context Window
Development Rules
Commit Messages
Follow Conventional Commits: feat: / fix: / docs: / refactor: / test: / chore:
Version Management
Keep all version surfaces in sync via ./scripts/sync-version.sh (the script is the SSOT for the target list — currently 7 strings across 6 files including .grok-plugin/plugin.json).
Normal feature/docs PRs must leave both files unchanged and record changes under CHANGELOG.md's [Unreleased] section.
Use ./scripts/sync-version.sh bump only when cutting a release.
CHANGELOG
Details: skills/harness-release/references/github-release.md (Keep a Changelog format; include Before/After tables for major changes)
Language
User-facing responses follow the explicit session or project language. If no
language is configured, use English. Use Japanese only when i18n.language: ja,
CLAUDE_CODE_HARNESS_LANG=ja, or an explicit session instruction requests
Japanese output.
Full details (how to switch, precedence, what does not change): docs/i18n.md.
Code Style
- Use clear and descriptive names
- Add comments for complex logic
- Keep agents/skills single-responsibility
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.
- 2d ago Changed e735965825c6
- 5d ago First seen · 188 lines · 4,080 tokens per session scan B eb93116299b8
claude-code-harness CLAUDE.md is an instructions file published in the GitHub repository Chachamaru127/claude-code-harness (3,082 stars, last pushed 4d ago), licensed MIT. It adds 4,080 tokens to every session, about $0.0204 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
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 oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
next.js AGENTS.md
Instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.