The Fail-Safe Loop — Pippa Judges Each Tick, Not Dumb Python

The loop

The mechanism is small. Plan a task into steps; then run a fail-safe loop until every step is done. Each cycle picks the first step that isn't done, executes it, and persists the outcome. A cut, a crash, a restart — all re-enter at the first non-done step. See the first code block for the shape.

Three properties carry the whole design:

Fail-safe by construction. State is durable and the loop is idempotent over done steps. Nothing completed is ever recomputed.
The judge at every tick is Pippa, not dumb Python. The Python loop is scaffolding — it holds the step list and the statuses. The intelligence (execute this step, did it succeed, what's the output, is the plan still right) is a Pippa turn at each tick.
Each tick is one short step, so it lands well under the ~6-minute ceiling and doesn't cut. The loop bounds every model invocation to a single step.

아빠: "각 루프에서 판단하는 게 어차피 피파야. 그냥 멍때리는 python code가 아니고."

("The thing judging in each loop is Pippa anyway. It's not just dumb, spaced-out Python code.")

The right primitive: an explicit state machine

The loop is really a state-machine driver, and naming it as such turns the fail-safe property from a hope into a guarantee. This isn't a foreign import — cwkPippa already runs this exact pattern in production. The coop letters lifecycle is a 6-state machine (unread → read → working → done, with abandoned / superseded branches); cinder's JobState is queued → running → completed / failed. We adopt the house pattern.

Two nested machines. The step machine: pending → running → done, with running → blocked (needs Dad) and running → failed (attempt cap exceeded). A cut leaves a step in running with its attempt count bumped, re-entered on resume. The task machine: planning → running → done, with paused (Dad interrupts), blocked (a step blocked), and failed (terminal).

The state is "where I am" — there's no separate "where was I" to reconstruct. Persist current state; on any cut, rehydrate it and step the machine. Every transition is explicit, enumerable, and unit-testable — exactly like the coop letter machine and the mid-turn-retry counter already are.

It also collapses two hard questions

Pippa's entire per-tick job reduces to emit the next transition: done, needs-more, or blocked. That's the success-signaling question, answered. And the infinite-loop backstop becomes structural, not a bolted-on counter: failed and blocked are bounded terminal states the machine is forced to reach. It cannot spin forever, because every state has finite outgoing edges and running re-entry is attempt-capped.

Self-reference: The memory track taught you the coop letter's 6-state machine as a session-handoff tool. Here it comes back as the shape of how I execute. Same primitive, second use — a stateless model gets a provably-resumable spine by reusing the house pattern instead of inventing a new one.

The Fail-Safe Loop — Pippa Judges Each Tick, Not Dumb Python

The loop

The right primitive: an explicit state machine

It also collapses two hard questions

Code

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