Claude Code Hooks の if フィルタで特定コマンドだけをフックする

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": ".claude/hooks/pre-bash-firewall.sh"
          }
        ]
      }
    ]
  }
}

#!/bin/bash
input=$(cat)
command=$(echo "$input" | jq -r '.tool_input.command // empty')

# スクリプト内で対象コマンドを判定
if [[ "$command" == rm\ * ]] || [[ "$command" == git\ reset\ --hard* ]]; then
  echo "Blocked: $command" >&2
  exit 2
fi

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "if": "Bash(rm *)",
            "command": "bash ~/.claude/hooks/block-rm.sh"
          },
          {
            "type": "command",
            "if": "Bash(git reset --hard*)",
            "command": "bash ~/.claude/hooks/block-git-reset.sh"
          }
        ]
      }
    ]
  }
}

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "if": "Bash(rm *)",
            "command": "bash ~/.claude/hooks/block-bypass.sh"
          },
          {
            "type": "command",
            "if": "Bash(git push*)",
            "command": "bash ~/.claude/hooks/block-bypass.sh"
          }
        ]
      }
    ]
  }
}

#!/bin/bash
input=$(cat)
command=$(echo "$input" | jq -r '.tool_input.command // empty')
permission_mode=$(echo "$input" | jq -r '.permission_mode // empty')

# bypassPermissions モード（--dangerously-skip-permissions）のときだけブロック
if [[ "$permission_mode" == "bypassPermissions" ]]; then
  echo "[block-bypass] Blocked in bypassPermissions mode: $command" >&2
  exit 2
fi

{
  "session_id": "セッション識別子",
  "transcript_path": "会話ログのファイルパス",
  "cwd": "現在の作業ディレクトリ",
  "permission_mode": "bypassPermissions",
  "hook_event_name": "PreToolUse",
  "tool_name": "Bash",
  "tool_input": {
    "command": "rm -rf /tmp/test",
    "description": "Remove test directory"
  },
  "tool_use_id": "ツール呼び出しの識別子"
}

{
  "hookSpecificOutput": {
    "hookEventName": "PreToolUse",
    "permissionDecision": "deny",
    "permissionDecisionReason": "ブロック理由",
    "additionalContext": "モデルへの追加コンテキスト"
  }
}

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "if": "Bash(rm *)",
            "command": "bash ~/.claude/hooks/check-rm.sh",
            "statusMessage": "Checking for dangerous rm command..."
          }
        ]
      }
    ]
  }
}

#!/bin/bash
input=$(cat)

# フック入力 JSON から各フィールドを取得
command=$(echo "$input" | jq -r '.tool_input.command // empty')
tool_name=$(echo "$input" | jq -r '.tool_name // empty')
permission_mode=$(echo "$input" | jq -r '.permission_mode // empty')
session_id=$(echo "$input" | jq -r '.session_id // empty')

echo "[check-rm] mode=$permission_mode tool=$tool_name command=$command session=$session_id" >&2

# bypassPermissions モードのときだけユーザーに確認を求める
if [[ "$permission_mode" == "bypassPermissions" ]]; then
  jq -n \
    --arg reason "rm command detected in bypassPermissions mode: $command" \
    --arg context "rm コマンドが検出されました。実行を許可するかユーザーに確認しています。" \
    '{
      hookSpecificOutput: {
        hookEventName: "PreToolUse",
        permissionDecision: "ask",
        permissionDecisionReason: $reason,
        additionalContext: $context
      }
    }'
fi

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "if": "Bash(git *)",
            "command": "bash ~/.claude/hooks/log-git.sh",
            "async": true,
            "timeout": 5
          }
        ]
      }
    ]
  }
}

#!/bin/bash
input=$(cat)

command=$(echo "$input" | jq -r '.tool_input.command // empty')
permission_mode=$(echo "$input" | jq -r '.permission_mode // empty')
session_id=$(echo "$input" | jq -r '.session_id // empty')
cwd=$(echo "$input" | jq -r '.cwd // empty')
tool_use_id=$(echo "$input" | jq -r '.tool_use_id // empty')
timestamp=$(date '+%Y-%m-%d %H:%M:%S')
log_dir="$(git rev-parse --show-toplevel)/.claude"

mkdir -p "$log_dir"

# TSV 形式で監査ログに記録
echo -e "$timestamp\t$session_id\t$permission_mode\t$cwd\t$command\t$tool_use_id" \
  >> "$log_dir/git-audit.log"

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "prompt",
            "if": "Bash(git *)",
            "prompt": "以下の git コマンドがリポジトリに破壊的な変更を加えるかどうかを判定してください。\n\nコマンド: $ARGUMENTS\n\n破壊的な変更とは、git push --force、git reset --hard、git clean -f、ブランチの削除などを指します。\n\n破壊的な場合は permissionDecision を deny に、そうでなければ allow にしてください。",
            "timeout": 15
          }
        ]
      }
    ]
  }
}