⌛️Claude Codeのhookが遅い原因を特定する

#!/usr/bin/env bash
# hook-latency-wrap.sh — 任意の hook をラップして実行時間を JSONL に記録
# 使い方: settings.json の command を以下に置き換える
#   "command": "~/.claude/scripts/hook-latency-wrap.sh /path/to/hook.sh"

set -uo pipefail

HOOK_BIN="${1:-}"
[ -z "$HOOK_BIN" ] && { echo "usage: $0 <hook-binary> [args...]" >&2; exit 64; }
shift || true

LOG_DIR="$HOME/.claude/logs"
mkdir -p "$LOG_DIR"
JSONL="$LOG_DIR/hook-latency.jsonl"

# EPOCHREALTIME = bash 5+ で SS.NNNNNN 形式（秒.マイクロ秒）
start_us=$(printf '%s' "${EPOCHREALTIME//./}" | sed 's/^0*//')
# 万一 EPOCHREALTIME が空(bash <5)なら python フォールバック
[ -z "$start_us" ] && start_us=$(python3 -c 'import time;print(int(time.time()*1000000))')

"$HOOK_BIN" "$@"
exit_code=$?

end_us=$(printf '%s' "${EPOCHREALTIME//./}" | sed 's/^0*//')
[ -z "$end_us" ] && end_us=$(python3 -c 'import time;print(int(time.time()*1000000))')

elapsed_ms=$(( (end_us - start_us) / 1000 ))
hook_name=$(basename "$HOOK_BIN")
ts=$(date -u +%Y-%m-%dT%H:%M:%S)

printf '{"ts":"%s","hook":"%s","elapsed_ms":%d,"exit_code":%d}\n' 

  "$ts" "$hook_name" "$elapsed_ms" "$exit_code" >> "$JSONL"

exit "$exit_code"

// 変更前
{
  "type": "command",
  "command": "~/.claude/hooks/cost_guard.sh"
}

// 変更後（1行変えるだけ）
{
  "type": "command",
  "command": "~/.claude/scripts/hook-latency-wrap.sh ~/.claude/hooks/cost_guard.sh"
}

"UserPromptSubmit": [
  {
    "hooks": [
      {
        "type": "command",
        "command": "~/.claude/scripts/hook-latency-wrap.sh ~/.claude/hooks/user_prompt_submit.sh"
      },
      {
        "type": "command",
        "command": "~/.claude/scripts/hook-latency-wrap.sh ~/.claude/hooks/cost_guard.sh"
      },
      {
        "command": "~/.claude/scripts/hook-latency-wrap.sh ~/.claude/hooks/model_routing_reminder.sh",
        "type": "command"
      }
    ]
  }
]

{"ts":"2026-06-21T20:10:41","hook":"cost_guard.sh","elapsed_ms":5196,"exit_code":0}
{"ts":"2026-06-21T20:10:33","hook":"obsidian_context.sh","elapsed_ms":827,"exit_code":0}
{"ts":"2026-06-21T20:11:18","hook":"skills-auto-update.sh","elapsed_ms":45705,"exit_code":0}

python3 - "$JSONL" "$DAYS" <<'PY'
import sys, json, datetime, collections
log, days = sys.argv[1], int(sys.argv[2])
cutoff = datetime.datetime.now() - datetime.timedelta(days=days)

stats = collections.defaultdict(list)
fail = collections.Counter()
total_records = 0
with open(log) as f:
    for line in f:
        try:
            r = json.loads(line)
            ts = datetime.datetime.fromisoformat(r["ts"])
            if ts < cutoff:
                continue
            total_records += 1
            stats[r["hook"]].append(r["elapsed_ms"])
            if r.get("exit_code", 0) not in (0, ):
                fail[r["hook"]] += 1
        except Exception:
            continue

rows = []
for hook, vals in stats.items():
    vals_sorted = sorted(vals)
    n = len(vals_sorted)
    p95 = vals_sorted[min(n-1, int(n*0.95))]
    rows.append((hook, n, sum(vals_sorted)//n, p95, vals_sorted[-1], fail.get(hook, 0)))
rows.sort(key=lambda r: -r[3])  # p95 降順

for hook, n, mean, p95, mx, fl in rows:
    flag = " ⚠" if p95 > 1500 else ""
    print(f"{hook:<32} {n:>5} {mean:>6}ms {p95:>6}ms {mx:>6}ms {fl:>5}{flag}")
PY

=== hook latency (last 7d, 29866 records) ===
hook                                 n    mean     p95     max  fail
----------------------------------------------------------------------
skills-auto-update.sh              365  46659ms  46114ms 1073920ms     0 ⚠
cost_guard.sh                     1493    605ms   2518ms   5802ms     0 ⚠
obsidian_context.sh                728  27816ms    782ms 19636398ms     1
model_routing_reminder.sh           23    148ms    451ms    641ms     0
pre_secrets_check.sh              2642     90ms    235ms   5561ms     0
user_prompt_submit.sh             1494     73ms    210ms    997ms     0
pre_env_guard.sh                  2642     59ms    154ms   4754ms     0
pre_git_guard.sh                  5726     43ms    117ms   2665ms     2
message_display_filter.sh        14753     47ms     96ms   5859ms     0