# Paid Tool Request Scoping and Receipt Binding Standard

> Paid Tool Request Scoping and Receipt Binding Standard is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-09-15).

Returns a decision procedure for scoping paid tool calls into minimal bounded request envelopes and binding expected receipts before approving spend, with kill criteria and post-settlement verification.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/agent-paid-tool-request-scoping-receipt-binding
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/paid-tool-request-scoping-and-receipt-binding-standard-dd7d0b84
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GtXrssObsthLueuovl29y

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 paid-tool-request-scoping-and-receipt-binding-standard-dd7d0b84
```

Example prompt: Walk me through the standard procedure for scoping a paid GET tool call into a minimal bounded request before I approve the spend, and tell me exactly how to bind and verify the receipt afterward.

## When to prefer this

Choose this endpoint when an autonomous agent needs a standardized, checkable procedure for safely scoping and approving any paid tool call — especially when working with x402 micropayments, unknown merchant response sizes, or when building spend-control guardrails. Prefer this over ad-hoc logic when you need explicit kill criteria for ambiguous responses and a post-settlement verification protocol baked in.

## Known failure modes

- Missing or malformed input type/method fields returns a validation error
- Ambiguous topic override may produce a generic rather than specific procedure
- LLM generation source may produce non-deterministic results across calls
- Payment not confirmed (paid: false) results in no procedure being returned
- Network timeout if the backing generation service is slow
- Incorrect HTTP method (e.g. POST instead of GET) returns method-not-allowed

## How this service works

Checkable procedure for an agent to scope any paid tool call into a minimal request envelope with bounded result size and explicit deliverable, then bind the expected receipt to that request before approving spend. Includes kill criteria for ambiguous or unbounded merchant responses and a verification step after settlement.

## Output

A structured JSON object containing a prose decision procedure (brief) for the agent, the topic and service slug, a generation source indicator (llm, reasoning, or deterministic), an ISO-8601 timestamp, and payment metadata including transaction reference and payer details. The brief describes the full scoping, receipt-binding, kill-criteria, and post-settlement verification workflow.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Paid tool request scoping and receipt binding standard paid response",
     "$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": "agent-paid-tool-request-scoping-receipt-binding",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "agent-paid-tool-request-scoping-receipt-binding",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/paid-tool-request-scoping-and-receipt-binding-standard-dd7d0b84/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)