Phase 1: webhook handler + systemd unit + flock in dev-task

agents/dev-task.sh

@@ -18,6 +18,15 @@ REPO="${1:-}"
 ISSUE="${2:-}"
 [[ -z "$REPO" || -z "$ISSUE" ]] && { echo "usage: $0 <owner>/<repo> <issue-id>" >&2; exit 64; }
 
+# Serialize: only one dev-task active at a time (Max-plan rate-limit pool).
+# Wait up to 60s for the lock; if still held, exit 75 so the webhook retries.
+LOCK_FILE="${LOCK_FILE:-/var/agent/dev-task.lock}"
+exec 200>"$LOCK_FILE"
+if ! flock -w 60 200; then
+  echo "[dev-task] another dev-task is running; backing off" >&2
+  exit 75
+fi
+
 MAX_WALLCLOCK="${MAX_WALLCLOCK:-30m}"
 MODEL_DEFAULT="${MODEL:-sonnet}"
 BASE_BRANCH="${BASE_BRANCH:-main}"