xp-harness: Skill for Claude Code

.apm/skills/e2e/SKILL.md

e2e is a skill for Claude Code, Codex from sei-newbear/xp-harness. It costs 149 tokens per session (584 once invoked), scanned A, original, MIT.

A guide for writing, editing, and reviewing end-to-end tests, which test a complete user journey through the application. It finds and follows the existing testing style for the part of the project being changed.

In plain words
What is it for?
Use it when adding scenarios, changing or debugging end-to-end test files, asking how to write them, or deciding that an end-to-end test is needed.
Why use it?
It prevents new tests from conflicting with the project's existing structure, naming, and conventions. It also keeps test-writing guidance separate from instructions for running the tests.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions CLAUDE.md; mentions AGENTS.md.

This is sei-newbear/xp-harness's own configuration. It tells Claude Code and Codex how to work on xp-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 xp-harness configures →

Reuse

Borrowing it

Nothing to install: this file belongs to sei-newbear/xp-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/sei-newbear/xp-harness/main/.apm/skills/e2e/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/sei-newbear/xp-harness

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for e2e

README.md
[![agentmods](https://agentmods.dev/badge/skills/sei-newbear/xp-harness/e2e/github.svg)](https://agentmods.dev/skills/sei-newbear/xp-harness/e2e)
Your own site
<a href="https://agentmods.dev/skills/sei-newbear/xp-harness/e2e"><img src="https://agentmods.dev/badge/skills/sei-newbear/xp-harness/e2e/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.

agentmods 80×15 button for e2e

Your own site · 80×15
<a href="https://agentmods.dev/skills/sei-newbear/xp-harness/e2e"><img src="https://agentmods.dev/badge/skills/sei-newbear/xp-harness/e2e.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 149 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 584 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00149 $0.00584
Opus 5.5 $0.00060 $0.00234
Sonnet 5.5 $0.00030 $0.00117
Haiku 4.5 $0.00015 $0.00058

Measured 2mo ago against content hash eb8c2b80e74d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

e2e 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 2mo 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.

.apm/skills/e2e/SKILL.md · 20 lines

What it actually says

E2E テストの流儀

プロジェクトの E2E の流儀 (spec の書き方・構造・命名) を spec 作業に効かせるためのスキル。流儀そのものはプロジェクト側にあり、このスキルはそれを探して効かせる入口。E2E を動かす手順 (環境・コマンド・CI) は e2e-execution skill の責務。

関連する E2E の流儀を探して従う

このスキルが呼ばれるたびに、以下を行う(1 つの作業の中で触る範囲が別の領域に移ったら、その都度やり直す):

  1. 触る範囲を特定する: いま読み書きしようとしているファイルのディレクトリ / 領域を特定する(例: front 配下と api 配下で流儀が分かれている場合、どちらの領域の作業かを特定する)
  2. 範囲に対応する E2E の流儀を探す:
    • セッションに登録されているスキル(このスキル自身を除く)にその範囲の E2E の流儀を扱うものがあれば、(参照して読むのではなく)スキルとして呼ぶ
    • スキルでない規約ファイル(その領域のディレクトリ配下の CLAUDE.md / AGENTS.md 等のドキュメント)があれば、読む
  3. 見つけた流儀に従って作業する
  4. 見つからなければ、流儀をでっち上げない: 一般に良いとされる判断で進める
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. 2mo ago First seen · 20 lines · 149 tokens per session scan A eb8c2b80e74d

Subscribe to this mod's changes

e2e is a skill published in the GitHub repository sei-newbear/xp-harness (9 stars, last pushed today), licensed MIT. It adds 149 tokens to every session and 584 once invoked, about $0.0006 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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