diff --git a/tools/subagent_spawn b/tools/subagent_spawn
index acf4f3b..090d64e 100755
--- a/tools/subagent_spawn
+++ b/tools/subagent_spawn
@@ -26,7 +26,7 @@ done
 
 [ $# -eq 0 ] && die "prompt required"
 
-name=${name:-$(date +%s%N)-$$}
+name=${name:-$(/bin/date +%s%N)-$$}
 # Prefix with parent session ID for global uniqueness.
 [ -n "$OLLIE_SESSION_ID" ] && name="${OLLIE_SESSION_ID}__${name}"
 cwd=${cwd:-$(pwd)}
@@ -48,8 +48,8 @@ model=${model}"
 printf '%s\n' "$kv" > "$OLLIE/s/new" || die "failed to create session"
 
 B="$OLLIE/s/$name"
-deadline=$(( $(date +%s) + 5 ))
-until [ -d "$B" ] || [ "$(date +%s)" -ge "$deadline" ]; do sleep 0.05; done
+SECONDS=0
+until [ -d "$B" ] || [ "$SECONDS" -ge 5 ]; do sleep 0.05; done
 [ -d "$B" ] || die "timeout waiting for session $name"
 
 printf '%s\n' "$prompt" > "$B/prompt" || die "failed to submit prompt"