codex-harness: Instructions file for Codex

AGENTS.md

codex-harness AGENTS.md is an instructions file for Codex, OpenCode from Chachamaru127/codex-harness. It costs 3,123 tokens per session, scanned A, original, MIT.

Repository instructions for Codex CLI development in the codex-harness project. The harness is a guide for running coding work through planning, implementation, and review stages.

In plain words
What is it for?
Use them when modifying the harness, its skills or rules, version scripts, changelog, or commit workflow.
Why use it?
They define how Codex reads instructions, manages versions, writes changelogs, and formats commits, reducing inconsistent project changes.

Instructions file for CodexOpenCode

Written for Codex and OpenCode: the file is AGENTS.md. Also seen: mentions CLAUDE.md; mentions Claude Code; reads ~/.codex paths.

This is Chachamaru127/codex-harness's own configuration. It tells Codex and OpenCode how to work on codex-harness itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything codex-harness configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Chachamaru127/codex-harness. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Chachamaru127/codex-harness/main/AGENTS.md
Clone the repo
git clone --depth 1 https://github.com/Chachamaru127/codex-harness

Made for: Codex, OpenCode.

Wrote this? Show the measurements

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README.md
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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.

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Per session 3,123 This file is loaded in full into every session.
When invoked 3,123 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.03123 $0.03123
Opus 5.5 $0.01249 $0.01249
Sonnet 5.5 $0.00625 $0.00625
Haiku 4.5 $0.00312 $0.00312

Measured 1mo ago against content hash 1f39d2829690, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

codex-harness AGENTS.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 1mo 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.

AGENTS.md · 272 lines

How it starts

The opening of the file, as written. The whole thing — 272 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md - Codex harness 開発ガイド

このファイルは Codex CLI がこのリポジトリで作業する際の指針です。

プロジェクト概要

Harness は、Codex CLI を「Plan → Work → Review」の型で運用するためのガイドです。

特殊な点: このプロジェクトは「ハーネス自身を使ってハーネスを改善する」自己参照的な構成です。

Codex CLI の前提

  • Codex は .codex/skills/<skill-name>/SKILL.md を読み込み、$skill-name で明示呼び出しする
  • Codex は AGENTS.override.md を優先し、次に AGENTS.md、必要なら設定された fallback 名を参照する
  • Hooks は未対応のため、暫定ガードは .codex/rules/*.rules の prefix_rule() で行う

開発ルール

コミットメッセージ

Conventional Commits に従う:

  • feat: - 新機能
  • fix: - バグ修正
  • docs: - ドキュメント変更
  • refactor: - リファクタリング
  • test: - テスト追加/更新
  • chore: - メンテナンス

バージョン管理

バージョンは VERSION がソース・オブ・トゥルース。 変更時は ./scripts/sync-version.sh bump を使用。

CHANGELOG 記載ルール(必須)

Keep a Changelog フォーマットに準拠

各バージョンエントリには以下のセクションを使用:

## [X.Y.Z] - YYYY-MM-DD

### Added
- 新機能について

### Changed
- 既存機能の変更について

### Deprecated
- 間もなく削除される機能について

### Removed
- 削除された機能について

### Fixed
- バグ修正について

### Security
- 脆弱性に関する場合

#### Before/After(大きな変更時のみ)

| Before | After |
|--------|-------|
| 変更前の状態 | 変更後の状態 |

セクション使い分け:

セクション 使うとき
Added 完全に新しい機能を追加したとき
Changed 既存機能の動作や体験を変更したとき
Deprecated 将来削除予定の機能を告知するとき
Removed 機能やコマンドを削除したとき
Fixed バグや不具合を修正したとき
Security セキュリティ関連の修正をしたとき

Before/After テーブル: 大きな体験変化(コマンド廃止・統合、ワークフロー変更、破壊的変更)があるときのみ追加。軽微な修正では省略可。

バージョン比較リンク: CHANGELOG.md 末尾に [X.Y.Z]: https://github.com/.../compare/vPREV...vX.Y.Z 形式で追加

コードスタイル

  • 明確で説明的な名前を使う
  • 複雑なロジックにはコメントを追加
  • コマンド/エージェント/スキルは単一責任に保つ

リポジトリ構成

claude-code-harness/
├── codex/              # Codex CLI 配布物
├── commands/           # Claude Code 向けコマンド
├── agents/             # サブエージェント定義(Task tool で並列起動可能)
├── skills/             # エージェントスキル
├── scripts/            # シェルスクリプト(ガード、自動化)
├── templates/          # テンプレートファイル
├── docs/               # ドキュメント
└── tests/              # 検証スクリプト

Read the full file on GitHub · 272 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. 1mo ago First seen · 272 lines · 3,123 tokens per session scan A 1f39d2829690

Subscribe to this mod's changes

codex-harness AGENTS.md is an instructions file published in the GitHub repository Chachamaru127/codex-harness (2 stars, last pushed 8mo ago), licensed MIT. It adds 3,123 tokens to every session, about $0.0125 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.

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