HELPER 09 · IDLE AUTOSAVE

The idle-autosave timeline

The handoff writes itself before the cache dies. Two paths home: pay re-cache once, or start fresh for free.

Idle autosave timeline from T+0 to T+6 minutes A horizontal timeline showing: watcher armed at T+0, polling window from T+0 to T+4, handoff written at T+4 (before cache expiry at T+5), and two return paths after that — continue in session or start fresh with the handoff already loaded. T+0:00 T+1:00 T+2:00 T+3:00 T+4:00 T+5:00 T+6:00 T+7:00 Minutes since your turn ended Stop hook arms watcher polls transcript mtime every 15s new activity re-arms the clock QUIET WINDOW · WATCHER POLLING Handoff written · ~$0.01 Haiku reads transcript tail Prompt cache expires 5-min TTL — re-cache now costs 12.5× per turn to resume 100K Opus session: $1.88 vs $0.15 / turn saved first WHEN YOU RETURN Continue this session Pay re-cache once (~$1.88) then back to normal cost /clear + /resume-session Fresh context, handoff pre-loaded effectively free or
Handoff cost
~$0.01
Haiku reads transcript tail at T+4
Re-cache penalty
12.5×
after 5-min cache expiry (TTL)
100K Opus session
$1.88
vs $0.15/turn with warm cache