The Fill Tape

The tape is the keeper's audit trail: one JSON file, keeper/data/fills.json (gitignored), overwritten each run with that run's outcomes. The app serves it at /api/fills and renders it in the blotter.

#Schema

{
  "fills": [
    {
      "desk": "0x8ff6ef04312679a0112b5229c6911cbc026e73ff",
      "leader": "0x…",
      "fillId": "demo-0x8ff6…",
      "symbol": "NVDA",
      "side": "buy",
      "action": "resize",
      "reason": "accepted with size reduced by caps",
      "intendedUsdg": "1000000000",
      "executedUsdg": "500000000",
      "slippageBps": 25,
      "source": "fixture",
      "session": "regular",
      "timestamp": "2026-01-07T15:00:00.000Z"
    }
  ]
}

#Honesty rules

These are enforced by the writer (keeper/src/fills.ts) and the API:

• source is a closed union: fixture | chain. Paper runs always write fixture.
• The file contains outcomes only — no keys, no secrets.
• The app renders the source label on every row, so a fixture row is visibly a fixture in the UI.

#Serving

app/src/app/api/fills/route.ts reads keeper/data/fills.json (trying both ../keeper/data and keeper/data relative to the app working directory) and returns { fills: [] } when the file is absent. It is force-dynamic, so each request reads the current file.

#Operational notes

• The file is overwritten per run, not appended — it is a latest-run view, not a history. Persist history by archiving the file per run if you need it.
• Because it is gitignored, a fresh clone has no tape; the blotter shows an empty tape until the keeper runs.
• Monitoring ideas and failure playbooks: Operations → Monitoring.