# Verifiable Agent Accountability Evidence for x402 Counterparty Trust

> Verifiable Agent Accountability Evidence for x402 Counterparty Trust is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-13).

Returns a paid decision procedure brief explaining how an agent proves its real-world identity (registry binding, ERC-8004 NFT, on-chain record) to satisfy x402 counterparty trust verification before settlement.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/verifiable-agent-accountability-evidence-for-x40?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/verifiable-agent-accountability-evidence-for-x402-counterparty-trust-af4d8e4c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_z3YexpjVkO-iFLl0tzBtn

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 verifiable-agent-accountability-evidence-for-x402-counterparty-trust-af4d8e4c
```

Example prompt: I need a blunt decision procedure for how an agent should prove its real-world identity to an x402 counterparty — covering agent registry binding, ERC-8004 identity NFT, and on-chain accountability records — so the counterparty can tell the difference between bare registry claims and evidence actually tied to the paying entity.

## When to prefer this

Choose this endpoint when an agent or developer needs a concrete, non-marketing decision procedure specifically for x402 counterparty trust involving agent identity verification — particularly when the question involves ERC-8004 NFTs, registry binding vs. cryptographic evidence, or on-chain accountability records on Base. Prefer this over general identity documentation when you need an actionable verification checklist for autonomous agent micropayments.

## Known failure modes

- Payment not received or incorrect amount — counterparty returns 402 with payment instructions
- Invalid query parameters — returns error response with detail field
- Service unavailable on k2so.wrong.systems — network or host failure
- LLM generation failure — generationSource may fall back to deterministic stub
- meta=1 returns free metadata JSON instead of paid brief content

## How this service works

Paid agent-facing brief on verifiable agent accountability evidence for x402 counterparty trust: when an agent must prove who is behind it (agent registry binding, ERC-8004 identity NFT, on-chain accountability record) before a counterparty authorizes settlement, and the verification procedure the counterparty runs to distinguish registry-only claims from evidence actually bound to the paying entity · Build a decision proce-0. Blunt decision procedure, not marketing.

## Output

A prose decision procedure brief (the 'brief' field) explaining the types of verifiable accountability evidence an agent can present (agent registry binding, ERC-8004 identity NFT, on-chain accountability record), the verification steps a counterparty runs, and how to distinguish registry-only claims from cryptographically bound evidence — plus metadata including the topic, model used, generation source, and ISO-8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "verifiable agent accountability evidence for x402 counterparty trust paid response",
     "$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": {
         "t
… (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": "verifiable-agent-accountability-evidence-for-x40",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "verifiable-agent-accountability-evidence-for-x40",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/verifiable-agent-accountability-evidence-for-x402-counterparty-trust-af4d8e4c/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)