docs: codex-keep-two無限ループ暴走問題の調査記録

ChatGPTのstring_smoke.nyash実行が無限ループ（CPU 99.9%）に
陥る問題を調査。原因はarchive/codex-keep-two-loop.shの
while trueによる無限監視ループだったことを確認。

現在は安全な単発実行版（codex-keep-two.sh）に置き換え済み。

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tools/archive/codex-keep-two-loop.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [ $# -lt 2 ]; then
+  echo "Usage: $0 <tmux_session> \"Task A\" \"Task B\" [\"Task C\" ...]" >&2
+  exit 1
+fi
+
+SESSION="$1"; shift
+TASKS=("$@")
+if [ ${#TASKS[@]} -lt 2 ]; then
+  echo "Provide at least two task strings." >&2
+  exit 1
+fi
+
+export CODEX_MAX_CONCURRENT=${CODEX_MAX_CONCURRENT:-2}
+export CODEX_DEDUP=${CODEX_DEDUP:-1}
+export CODEX_NOTIFY_MINIMAL=${CODEX_NOTIFY_MINIMAL:-1}
+
+WORK_DIR="$HOME/.codex-async-work"
+RUN_DIR="$WORK_DIR/running"
+mkdir -p "$RUN_DIR"
+
+idx=0
+echo "[keep-two-loop] Maintaining ${CODEX_MAX_CONCURRENT} concurrent tasks. Ctrl-C to stop." >&2
+while true; do
+  # Count running by sentinel first, fallback by pgid
+  RUN=0
+  if [ -d "$RUN_DIR" ]; then
+    RUN=$(ls -1 "$RUN_DIR"/codex-*.run 2>/dev/null | wc -l | tr -d ' ' || echo 0)
+  fi
+  if [ "${RUN:-0}" -eq 0 ] && command -v pgrep >/dev/null 2>&1; then
+    RUN=$(pgrep -f -- 'codex .* exec' | xargs -r -I {} sh -c 'ps -o pgid= -p "$1" 2>/dev/null' _ {} | awk '{print $1}' | sort -u | wc -l | tr -d ' ' || echo 0)
+  fi
+
+  NEED=$((CODEX_MAX_CONCURRENT - ${RUN:-0}))
+  if [ $NEED -gt 0 ]; then
+    echo "[keep-two-loop] running=$RUN; starting $NEED task(s)…" >&2
+    for ((i=0; i<NEED; i++)); do
+      task="${TASKS[$idx]}"; idx=$(((idx+1) % ${#TASKS[@]}))
+      CODEX_ASYNC_DETACH=1 ./tools/codex-async-notify.sh "$task" "$SESSION" >/dev/null 2>&1 || true
+      sleep 0.2
+    done
+  fi
+  sleep 2
+done
+
+