etf flows derived

{
  "input": {
    "type": "http",
    "method": "GET",
    "queryParams": {}
  },
  "output": {
    "type": "json",
    "errors": {
      "400": {
        "example": {
          "error": "invalid request"
        },
        "description": "Invalid or missing parameter(s). Returned before the payment gate on paid requests, so a malformed call is never charged. JSON body: { error: <what is wrong and how to fix it> } plus usage hints."
      },
      "402": {
        "description": "Payment required — x402 v2 challenge; the accepts array lists scheme, network, and amount. Retry the same request with a PAYMENT-SIGNATURE (v2) or X-PAYMENT (v1) header. Verification is free."
      },
      "500": {
        "example": {
          "error": "upstream_failed"
        },
        "description": "Unexpected server error. If a payment settled without a usable result, contact info@theaslangroupllc.com with the settlement tx hash for a re-run or credit."
      }
    },
    "example": {
      "assets": [
        {
          "asset": "BTC",
          "headline": "Spot BTC ETFs post a third straight day of net inflows, led by IBIT",
          "flow_read": "5-day net inflow accelerating vs the prior 5-day window — a strengthening institutional bid."
        }
      ],
      "deterministic": {
        "assets": [
          {
            "asset": "BTC",
            "aggregate": {
              "trend": "accelerating_inflow",
              "streak_days": 3,
              "streak_direction": "inflow"
            }
          }
        ]
      },
      "cross_asset_read": "BTC inflows while ETH holds flat — no rotation signal yet."
    }
  }
}