DAY 4 · 2026-06-15

Day 4 — record and recover

Built a flight-recorder-style safety net so the system survives a crash without coming back broken.

Anything that runs around the clock will eventually crash — a power blip, a bug, a bad update. The real question isn't whether it happens, it's whether the system comes back clean or comes back broken. Day 4 added the equivalent of a flight recorder plus a startup checklist. Every time the system starts, it opens a fresh record of what it's about to do; every time it stops, it closes that record out. If it crashes mid-task, the next startup sees the unfinished record, knows a crash happened, notes it, and recovers — instead of waking up confused and carrying on in a bad state. The critical detail: we built this safety net so it can never itself cause a crash, because a safety feature that can take down the thing it's protecting is worse than no safety feature at all.

Done

  • Added start-up and shut-down steps that open a session record when the system launches and close it out when it stops — written to disk in a way that can't be left half-finished even if the power is cut mid-write.
  • Built those steps to be fail-safe: even if one of them hits a bug, it's designed to do nothing rather than crash the system. This matters because the system is set to restart itself automatically on failure, so a buggy safety check could otherwise trap it in an endless crash-and-restart loop.
  • Tested recovery for real, including deliberately faking a crash: the system correctly spotted the unclean shutdown, counted it, and logged the recovery — rather than silently pretending nothing happened.
  • Ran a real stop-start cycle and confirmed everything came back up clean: fresh record opened, all workers running again, no errors.

Tomorrow

  • Split the single worker into a three-stage assembly line — plan it, then write it, then check it — and design a careful, tightly controlled way for the system to begin improving itself.

Worth knowing

  • A safety mechanism that can crash the thing it's protecting isn't safety. This one is built so the worst it can ever do is nothing at all.

Quota

Compute budget: nominal.

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