# ETF Brief – Spot Bitcoin/Ethereum ETF Flow Summary

> ETF Brief – Spot Bitcoin/Ethereum ETF Flow Summary is a paid API for AI agents from api.agentstools.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Returns a one-call aggregated brief for spot BTC or ETH ETFs including net flow, inflow/outflow streak, cumulative window flow, momentum, issuer concentration, total AUM, and an accumulation/distribution/neutral verdict.

## Facts

- Endpoint: GET https://api.agentstools.dev/etf/brief
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/etf-brief-spot-bitcoin-ethereum-etf-flow-summary-9536fc27
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_S3ZkYBPQZwxPI5-Qp0J4H

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability etf-brief-spot-bitcoin-ethereum-etf-flow-summary-9536fc27
```

Example prompt: Give me the full ETF flow brief for spot Bitcoin ETFs in the US — net flow, streak, momentum, issuer concentration, AUM, and whether the market is in accumulation or distribution.

## When to prefer this

Use this endpoint when you need a comprehensive, pre-computed ETF flow intelligence brief for spot Bitcoin or Ethereum ETFs in a single API call, avoiding the need to query multiple issuer endpoints and perform your own differencing and aggregation. Ideal for agents that need a fast, deterministic accumulation/distribution verdict alongside AUM and momentum without building custom analytics pipelines.

## Known failure modes

- Invalid asset value (not 'btc' or 'eth') returns a validation error
- Invalid region value (not 'us' or 'hk') returns a validation error
- HK region may return scaffold/incomplete data as it is noted as a scaffold
- Payment failure or missing x402 payment header results in 402 response
- Upstream data source unavailability may result in stale or missing flow data

## How this service works

Fusion flow brief for spot Bitcoin or Ethereum ETFs in ONE call: latest total net flow, the inflow/outflow streak, the window cumulative, flow momentum, issuer concentration, total AUM and a deterministic accumulation, distribution or neutral verdict. Saves several issuer queries plus the differencing.

## Output

A structured JSON object containing: latest total net flow (USD), the current inflow or outflow streak length, cumulative flow over the reporting window, flow momentum indicator, issuer concentration metric, total AUM across all issuers, and a deterministic categorical verdict of 'accumulation', 'distribution', or 'neutral' — all in a single response without requiring multiple issuer-level queries.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "asset",
      "region"
     ],
     "properties": {
      "asset": {
       "enum": [
        "btc",
        "eth"
       ],
       "type": "string",
       "description": "Crypto asset whose spot ETFs to report: btc or eth."
      },
      "region": {
       "enum": [
        "us",
        "hk"
       ],
       "type": "string",
       "description": "ETF listing region: us (live) or hk (scaffold)."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/etf-brief-spot-bitcoin-ethereum-etf-flow-summary-9536fc27/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.agentstools.dev](https://www.zero.xyz/host/api.agentstools.dev/llms.txt)