# Auditor response — 2026-04-25 — Option B prompt sent to dev

## Action taken

Pasted the Option B (REST polling watcher) prompt into the developer CLI tmux session (SM:0). Dev session began processing immediately.

The prompt is self-contained and constrained:
- New directory `tools/spread-watcher/` only — zero changes to `engine/`, `dashboard/`, `config/`, `ops/`, root.
- 4 venues (kraken, coinbase, binance, okx), 2 currencies (BTC, ETH).
- 1Hz REST polling, JSONL output, separate analysis script for the markdown report.
- 6 unit tests, no DB, no websockets, no engine integration.
- Explicit "out of scope" list to prevent scope creep.

## What happens next

1. Dev finishes implementation (rough estimate: minutes to ~1 hour).
2. Auditor verifies via the dev session output and a smoke test.
3. Operator (you) starts the watcher: `cd tools/spread-watcher && npm run watch` (or however the dev wires it). Recommend running it in a tmux/systemd-detached process so it survives this SSH session.
4. Watcher runs for **2–8 hours** to accumulate enough observations across venues and time-of-day. Auditor would suggest at least 4 hours to capture a US session window plus an Asia session window.
5. Operator runs `npm run analyze -- --from <iso> --to <iso>` and shares the report (or asks the auditor to read it from disk).
6. Auditor delivers the interpretation per your spec:
   - **Is there real opportunity?** (look at p99 gross_spread vs round-trip fees)
   - **Which exchanges look promising?** (the venue-pair ranking)
   - **Continue, expand, or pivot?** (decision against the framework already published)

## Decisions held / parked

- **Vendor data research (Tardis/Kaiko)** — held until Option B results, per your instruction.
- **Full replay system** — held indefinitely. Will only revisit if Option B + Option A are both inconclusive.
- **Live WS multi-venue (Option A)** — held. Will only escalate if Option B identifies a specific venue-pair worth tick-level scrutiny.

## Open

Nothing requires your input right now. Auditor will re-check the dev session shortly and report when the watcher is ready to start.