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/sei-newbear/xp-harness/api-implementationnpx skills add sei-newbear/xp-harness --skill api-implementationgit clone --depth 1 https://github.com/sei-newbear/xp-harnessWhat 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 | $0.00091 | $0.00661 |
| Opus 5 | $0.00046 | $0.00331 |
| Sonnet 5 | $0.00018 | $0.00132 |
| Haiku 4.5 | $0.00009 | $0.00066 |
Grade A, and why
api-implementation 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.
What it actually says
api の実装規約（クリーンアーキテクチャ）
レイヤ構成（src/ 配下）
内側から外側へ 4 レイヤに分離する。依存の向きは常に外→内（外側が内側を知る。内側は外側を知らない）:
- domain/: エンティティと、それ自体で完結するドメインのルール。外部依存なし（DB も HTTP も知らない）。例:
Task型、優先度の順序（high > mid > low）の比較ルール - usecase/: アプリケーションのユースケース。ドメインを使い、処理を束ねる。永続化は repository のインターフェース越し に使う（実装は知らない）
- gateway/: repository インターフェースの実装。永続化（PostgreSQL）を担う
- route/: HTTP のハンドリング（Hono）。usecase を呼び、結果を HTTP に変換する
repository のインターフェースは usecase 側が要求する形で定義し（例: usecase/ports.ts）、gateway がそれを実装する（依存性の逆転）。
テスト戦略
- ロジックのある内側（domain / usecase）はユニットテストで駆動する（
*.test.tsを対象ファイルの隣に置く、npm test= vitest）。usecase のテストでは repository インターフェースをモックに差し替え、ロジックだけを検証する - gateway（DB アクセス）と route（HTTP 配線）は E2E で担保する（薄い配線・永続化はユニットテストを書かず、フルスタック E2E がカバーする）
その他
- 型定義は
typeエイリアスを使う（interfaceは使わない） - 公開関数には 1 行の JSDoc コメントを必ず書く
- エラーは内側の層で throw せず戻り値で返し、route 層で HTTP status に変換する
- 永続化先は PostgreSQL。接続は
src/db.tsのpoolを使う（envDATABASE_URL、pool.query(...)）。SQL を書くのは gateway だけ
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 First seen · 29 lines · 91 tokens per session scan A 7299f00651ae
api-implementation is a skill published in the GitHub repository sei-newbear/xp-harness (9 stars, last pushed 25d ago), licensed MIT. It adds 91 tokens to every session and 661 once invoked, about $0.0005 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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