# Per-Facilitator x402 Reliability and Scale Vetting Procedure

> Per-Facilitator x402 Reliability and Scale Vetting Procedure is a paid API for AI agents from k2so-8080.on.ascii.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-20).

Returns a deterministic decision procedure for agents evaluating x402 facilitators on reliability, cost, scale, payload version compatibility, and failure-mode handling at high transaction volume.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/per-facilitator-x402-reliability-and-scale-vetti?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/per-facilitator-x402-reliability-and-scale-vetting-procedure-d33bb99e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WGyderIt-996VVl_z55ZG

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 per-facilitator-x402-reliability-and-scale-vetting-procedure-d33bb99e
```

Example prompt: I'm running high transaction volume through x402 and need to pick between several facilitators — can you walk me through the full vetting procedure, including settle-on-rail verification, cost-per-call analysis, scale evidence scoring, payload version compatibility, and how to handle settlement timeouts and retry storms?

## When to prefer this

Use this endpoint when an agent needs a structured, ordered vetting procedure specifically for x402 facilitator selection at high transaction volume, particularly when payload version compatibility, cost analysis, and failure-mode resilience all need to be evaluated together. Prefer this over generic payment provider comparison tools when the agent is operating in the x402 protocol ecosystem and needs actionable decision logic rather than raw data.

## Known failure modes

- Payment not completed — returns 402 challenge requiring USDC payment before content is delivered
- Facilitator data unavailable — procedure may rely on general heuristics if live 402 challenge cannot be completed
- Topic override ignored — unrecognized topic strings may fall back to default procedure
- Timeout — slow response if underlying LLM or reasoning engine is under load
- Stale guidance — generatedAt timestamp may indicate cached or older decision procedure

## How this service works

Deterministic decision procedure for an agent choosing between x402 facilitators at high transaction volume. Ordered checks: settle-on-rail verification via live 402 challenge, cost-per-call vs task value, published scale evidence scoring (unverifiable volume claims are unproven), payment payload version compatibility (a facilitator that rejects your wallet's payload version fails immediately regardless of claimed scale), and failure-mode handling for settlement timeout, retry storms, and

## Output

A structured prose decision procedure (brief) with ordered checks: settle-on-rail verification via live 402 challenge, cost-per-call vs task value comparison, scale evidence scoring with notes on unverifiable claims, payment payload version compatibility assessment, and failure-mode guidance for settlement timeout and retry storms. Includes metadata like generationSource, model used, and ISO-8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Per-facilitator x402 reliability and scale vetting procedure paid response",
     "$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": "s
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/per-facilitator-x402-reliability-and-scale-vetting-procedure-d33bb99e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so-8080.on.ascii.dev](https://www.zero.xyz/host/k2so-8080.on.ascii.dev/llms.txt)