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 skills/chachamaru127/claude-code-harness/harness-worknpx skills add Chachamaru127/claude-code-harness --skill harness-workgit 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/skills/chachamaru127/claude-code-harness/harness-work)<a href="https://agentmods.dev/skills/chachamaru127/claude-code-harness/harness-work"><img src="https://agentmods.dev/badge/skills/chachamaru127/claude-code-harness/harness-work.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 | $0.00057 | $0.14308 |
| Opus 5 | $0.00028 | $0.07154 |
| Sonnet 5 | $0.00011 | $0.02862 |
| Haiku 4.5 | $0.00006 | $0.01431 |
Grade A, and why
harness-work 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 5d 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 — 832 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Harness Work
Harness の統合実行スキル。 以下の旧スキルを統合:
work— Plans.md タスクの実装（スコープ自動判断）impl— 機能実装（タスクベース）breezing— チームフル自動実行parallel-workflows— 並列ワークフロー最適化ci— CI 失敗時の復旧
Quick Reference
| ユーザー入力 | モード | 動作 |
|---|---|---|
harness-work |
auto | タスク数で自動判定（下記参照） |
harness-work all |
auto | 全未完了タスクを自動モードで実行 |
harness-work 3 |
solo | タスク3だけ即実行 |
harness-work --parallel 5 |
parallel | 5ワーカーで並列実行（強制） |
harness-work --codex |
codex | Codex CLI に委託（明示時のみ） |
harness-work --breezing all |
breezing | resolved backend でチーム実行（配布既定は claude、user/project default で cursor 可） |
harness-work --breezing --backend cursor all |
breezing | Cursor worker backend を明示してチーム実行 |
harness-work --breezing --backend claude all |
breezing | Codex native subagent worker を明示してチーム実行 |
harness-work --breezing |
breezing | チーム実行を強制 |
harness-work 3 --plan roadmap |
solo | named Plans の roadmap からタスク3を実行 |
Execution Mode Auto Selection（フラグなし時の自動判定）
明示的なモードフラグ（--parallel, --breezing, --codex）がない場合、
対象タスク数に応じて最適なモードを自動選択する:
| 対象タスク数 | 自動選択モード | 理由 |
|---|---|---|
| 1 件 | Solo | オーバーヘッド最小。直接実装が最速 |
| 2〜3 件 | Parallel（Task tool） | Worker 分離のメリットが出始める閾値 |
| 4 件以上 | Breezing | Lead 調整 + Worker 並列 + Reviewer 独立の三者分離が効果的 |
ルール
- 明示フラグは常にオートモードを上書きする
--parallel N→ Parallel モード（タスク数に関係なく）--breezing→ Breezing モード（タスク数に関係なく）--codex→ Codex モード（タスク数に関係なく）
--codexは明示時のみ発動。Codex CLI が未インストールの環境があるため、自動選択しない--codexは他モードと組み合わせ可能:--codex --breezing→ Codex + Breezing
Execution Backend Selection（実装バックエンド選択）
バックエンド（どのランタイムが実装するか）は、トポロジー（実行モード: solo / parallel / breezing）と直交する。 トポロジーが「何ワーカーで・どう分割して回すか」を決めるのに対し、バックエンドは「実装の手を誰が動かすか」を決める。 この契約は host-neutral であり（spec.md「Execution Backend Contract」）、Codex host から harness を駆動しても Claude Code から駆動しても同じに振る舞う。
| backend | 実装の担い手 | 委託コマンド |
|---|---|---|
claude（global fallback） |
Codex native subagent（spawn_agent） |
spawn_agent で worker を spawn |
codex |
Codex CLI | bash "${HARNESS_PLUGIN_ROOT}/scripts/codex-companion.sh" task --write "<prompt>" |
cursor |
cursor-agent（model composer-2.5-fast） |
bash "${HARNESS_PLUGIN_ROOT}/scripts/cursor-companion.sh" task --write --workspace <worktree> "<prompt>" |
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 5d ago First seen · 832 lines · 57 tokens per session scan A 6295b2f45a99
harness-work is a skill published in the GitHub repository Chachamaru127/claude-code-harness (3,087 stars, last pushed 5d ago), licensed MIT. It adds 57 tokens to every session and 14,308 once invoked, about $0.0003 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 2026-08-30.
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