server-startup

A guide for starting and stopping development servers during end-to-end tests or browser checks. It requires using the project’s assigned ports and restarting both frontend and backend services together.

In plain words
What is it for?
Use it to stop existing processes, start the required services on their specified ports, run browser or API checks, and confirm the ports are stopped afterward.
Why use it?
It prevents port conflicts and avoids testing an old server whose code does not include the latest changes.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/crearize/ai-dev-helm/server-startup
Any agent
npx skills add Crearize/ai-dev-helm --skill server-startup
Clone the repo
git clone --depth 1 https://github.com/Crearize/ai-dev-helm

Made for: Claude Code, Codex.

Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,392 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00052 $0.01392
Opus 5 $0.00026 $0.00696
Sonnet 5 $0.00010 $0.00278
Haiku 4.5 $0.00005 $0.00139

Measured 3d ago against content hash 6fd0e599fd98, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

server-startup 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 3d 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.

skills/project/server-startup/SKILL.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Server Startup Skill - 開発サーバー起動

禁止事項(最重要)

以下は絶対に禁止。違反は許容されない。

  • ポート変更禁止: プロジェクトで指定されたポート以外での起動は禁止
  • ポート競合時に別ポート使用禁止: 必ず既存プロセスを停止する
  • 片方だけの起動禁止: 再起動時はフロントエンド・バックエンド両方を必ず再起動する
  • 停止確認省略禁止: 作業完了後はポートがLISTENしていないことまで確認する

適用対象

以下の作業では、必ずこのスキルを使用する。

  • 開発サーバーの起動・再起動
  • E2Eテスト
  • ブラウザ検証
  • UI実装後の動作確認
  • API疎通確認

worktree内で作業している場合は、worktree-parallel スキルで渡されたポートレジストリ(メインチェックアウト直下の .worktrees/.ports.json)で割り当てられたポートを「プロジェクト指定ポート」として扱う。

再起動手順(必須)

サーバーを使う作業の開始時は、必ず以下の手順を順番に実行すること。

Step 1: 既存プロセスの停止(毎回必ず実行)

起動前に必ず既存プロセスを確認し、動いていれば停止する。 この手順をスキップしてはならない。

Windows(MSYS/Git Bash):

# ポート確認と停止
netstat -ano | grep ":[PORT] " | grep LISTENING
# LISTENINGがあれば → taskkill //PID <PID> //F

Windows(PowerShell):

$connections = Get-NetTCPConnection -LocalPort [PORT] -State Listen -ErrorAction SilentlyContinue
$connections | Select-Object -ExpandProperty OwningProcess -Unique | ForEach-Object {
  Stop-Process -Id $_ -Force
}

macOS / Linux:

# ポート確認と停止
lsof -i :[PORT]
# プロセスがあれば → kill -9 <PID>

なぜ必須か: 古いプロセスが残っていると、新しいプロセスがEADDRINUSEで起動失敗し、 古い(コード変更が反映されていない)サーバーが動き続ける。

Step 2: バックエンド起動

プロジェクトの CLAUDE.md に記載されたバックエンド起動コマンドを実行する。 worktree内では、渡されたポートレジストリのバックエンド割当ポートを使用する。

Step 3: フロントエンド起動

プロジェクトの CLAUDE.md に記載されたフロントエンド起動コマンドを実行する。 worktree内では、渡されたポートレジストリのフロントエンド割当ポートを使用する。

Step 4: 起動確認(両方確認すること)

バックエンド・フロントエンドの両方がレスポンスを返すことを確認する。

両方が正常応答するまで起動完了とみなさない。

Step 5: 起動失敗時のログ確認

バックグラウンド実行したコマンドの出力を必ず確認し、 EADDRINUSEFAILED TO STARTError 等がないことを確認する。


サーバー停止手順(作業完了後に必須)

E2Eテストやサーバーを使う作業が完了したら、必ずサーバーを停止すること。 サーバーを起動したまま放置すると、プロセスが大量に残りリソースを消費する。

停止手順

Windows(MSYS/Git Bash):

netstat -ano | grep ":[PORT] " | grep LISTENING
# LISTENINGがあれば → taskkill //PID <PID> //F //T

Windows(PowerShell):

$connections = Get-NetTCPConnection -LocalPort [PORT] -State Listen -ErrorAction SilentlyContinue
$connections | Select-Object -ExpandProperty OwningProcess -Unique | ForEach-Object {
  Stop-Process -Id $_ -Force
}

Read the full file on GitHub · 136 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. 3d ago First seen · 136 lines · 52 tokens per session scan A 6fd0e599fd98

Subscribe to this mod's changes

server-startup is a skill published in the GitHub repository Crearize/ai-dev-helm (4 stars, last pushed 8d ago), licensed MIT. It adds 52 tokens to every session and 1,392 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 2026-08-31.

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