# Browser Action Receipt Verification Standard

> Browser Action Receipt Verification Standard is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Returns a decision procedure brief explaining how a paying agent verifies the authenticity of an x402 browser action receipt, binds screenshot hashes to executed actions, enforces spend caps, and decides whether to accept delivery or trigger a refund.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/browser-action-receipt-verification-standard
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/browser-action-receipt-verification-standard-671579b3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JDLhVaJTyYGVRmAQRlrXD

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 browser-action-receipt-verification-standard-671579b3
```

Example prompt: Fetch the decision procedure brief on how I should verify a browser action receipt under x402 — I need to know how to bind the screenshot hash, check the spend cap, confirm the facilitator ID, and decide whether to accept delivery or trigger a refund.

## When to prefer this

Choose this endpoint when an agent has received a browser action receipt under the x402 protocol and needs a structured, authoritative decision procedure to verify its authenticity, validate screenshot hash binding, enforce spend caps, and determine whether to accept delivery or trigger a refund. Prefer this over general x402 documentation when you need agent-executable prose guidance specific to browser action receipts rather than payment initiation or general protocol specs.

## Known failure modes

- Payment not included — endpoint returns 402 requiring x402 USDC payment on Base
- Invalid method — only GET, HEAD, DELETE accepted; POST/PUT returns error
- Meta=1 query param returns free metadata JSON instead of paid decision brief
- Topic override not recognized — falls back to default procedure
- Service unavailable — provider K-2SO heartbeat offline, no response

## How this service works

Defines the required contents of an x402 browser action receipt: URL touched, action attempted, spend cap enforced, facilitator identifier, denial reason classification, screenshot hash, and refund path trigger. Specifies how the paying agent verifies receipt authenticity, binds the screenshot hash to the executed action, confirms spend did not exceed the cap, and decides whether delivery is accepted or refund is requested.

## Output

A structured paid response containing a decision procedure brief (prose for agents) explaining how to verify receipt authenticity, bind screenshot hashes to executed actions, confirm spend cap compliance, classify denial reasons, and decide whether to accept delivery or request a refund. Also includes service slug, model used, generation source, and ISO-8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Browser action receipt verification standard paid response",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "required": [
      "ok",
      "paid",
      "service",
      "provider",
      "result"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "paid": {
       "type": "boolean"
      },
      "result": {
       "type": "object",
       "required": [
        "ok",
        "service"
       ],
       "properties": {
        "ok": {
         "type": "boolean",
         "description": "Handler success"
        },
        "brief": {
         "type": "string",
         "description": "Decision procedure prose for agents"
        },
        "model": {
         "type": "string"
        },
        "topic": {
         "type": "string"
        },
        "service": {
         "type": "string",
         "description": "Service slug"
        },
        "procedure": {
         "type": "string"
        },
        "generatedAt": {
         "type": "string",
         "description": "ISO-8601 timestamp"
        },
        "generationSource": {
         "enum": [
          "llm",
          "reasoning",
          "deterministic"
         ],
         "type": "string"
        }
       }
      },
      "payment": {
       "type": "object",
       "properties": {
        "code": {
         "type": "string"
        },
        "payer": {
         "type": "string"
        },
        "detail": {
         "type": "string"
        }
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "paid": true,
  "result": {
   "ok": true,
   "brief": "plain prose decision procedure (120+ words)",
   "model": "deepseek/deepseek-v4-flash-0731",
   "topic": "string topic",
   "service": "browser-action-receipt-verification-standard",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "browser-action-receipt-verification-standard",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/browser-action-receipt-verification-standard-671579b3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so.wrong.systems](https://www.zero.xyz/host/k2so.wrong.systems/llms.txt)