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/masamunet/npm-dev-mcp/agents-mdgit clone --depth 1 https://github.com/masamunet/npm-dev-mcpWrote 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/masamunet/npm-dev-mcp/agents-md)<a href="https://agentmods.dev/instructions/masamunet/npm-dev-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/masamunet/npm-dev-mcp/agents-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 | $0.00918 | $0.00918 |
| Opus 5 | $0.00459 | $0.00459 |
| Sonnet 5 | $0.00184 | $0.00184 |
| Haiku 4.5 | $0.00092 | $0.00092 |
Grade A, and why
npm-dev-mcp 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 4d 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
Repository Guidelines
プロジェクト構成と配置
- エントリーポイントは
src/index.ts、ビルド成果物はdist/に生成されます(npm run build)。 - コア機能は
src/components/(プロセス・ポート・ログ管理)、src/tools/(MCPツール定義)、src/cli/(コマンド登録と出力整形)に分割。 - 実行時設定・健康チェックは
src/config/とsrc/components/HealthEndpoint.ts、状態復旧はsrc/components/StateManager.ts。 - テストは
tests/配下とsrc/**/__tests__/を対象に Jest が走ります。 - ログと PM2 用設定は
logs/とecosystem.config.jsを参照してください。
ビルド・テスト・開発コマンド
npm run dev: TypeScript をウォッチコンパイル(開発用)。npm run build:tscでdist/を生成(公開前フロー)。npm start: ビルド済みdist/index.jsを実行。npm test/npm run test:watch/npm run test:coverage: Jest 実行。Coverage はcoverage/に出力。- 運用プロセス管理:
npm run pm2:start|stop|restart|delete|logs|monit|status(ecosystem.config.jsを基に pm2 で常駐)。
コーディングスタイル・命名
- 言語: TypeScript (ES2022,
module=NodeNext, ESM import は拡張子.jsを付与)。 - インデント2スペース、セミコロン必須、シングルクォート推奨。
- 型安全を優先(
strict: true)。パブリック API は明示的な型・インターフェースを付与。 - ロガーは
utils/logger.tsのシングルトンを利用し、標準出力汚染を避ける。 - ファイル/クラス名は役割ベース(例:
*Manager,*Handler,*Schema)。
テスト指針
- フレームワーク: Jest + ts-jest (ESM)。対象パターン:
**/__tests__/**/*.test.tsおよび**/*.(spec|test).ts。 - 可能ならユースケース単位でモジュールを分離し、プロセス管理系はモックで外部副作用を隔離。
- 新機能は少なくとも正常系と主要なエラー系を追加し、
npm run test:coverageで回帰確認。
コミットと Pull Request
- 既存ログは短い命令形/バージョンタグ例 (
Fix ...,1.1.4)。同様のトーンで簡潔に。 - PR には目的、変更点、テスト結果(実行コマンド名と要約)、関連 Issue/チケットを記載。
- 機能やCLI挙動が変わる場合は README/ヘルプ出力の更新を忘れずに。スクリーンショットよりは実行ログや例を添付するとレビューしやすい。
セキュリティ・運用メモ
- Node.js 18+ を前提。
.envは自動検出されるため、秘密情報はコミットしないこと(.gitignoreを尊重)。 - デーモン化時は pm2 のログローテーション設定を確認し、
logs/の肥大化を定期確認。 - MCP 経由でツールを公開する場合、外部入力は
SafeErrorHandlerを通し、例外は JSON で整形して返却する。
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.
- 4d ago First seen · 38 lines · 918 tokens per session scan A 45c04fcbf182
npm-dev-mcp AGENTS.md is an instructions file published in the GitHub repository masamunet/npm-dev-mcp (0 stars, last pushed 8mo ago), licensed MIT. It adds 918 tokens to every session, about $0.0046 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.
Other instructions, from other repositories
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AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
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AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
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vscode oss-third-party-notices.instructions.md
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