# x402 New-Rail Rollout Decision Procedure with CDN Stale-Challenge Handling

> x402 New-Rail Rollout Decision Procedure with CDN Stale-Challenge Handling 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 2026-10-23).

Returns a PASS or ROLLBACK decision for safely adding a new payment settlement rail to a live x402-metered endpoint, covering CDN stale-challenge mitigation, pre-flight capability checks, staged rollout, and rollback criteria.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/x402-endpoint-new-rail-rollout-procedure-for-mer?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-new-rail-rollout-decision-procedure-with-cdn-stale-challenge-c333bf1e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_66JrvjAIKeF03gwfnv9bR

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 x402-new-rail-rollout-decision-procedure-with-cdn-stale-challenge-c333bf1e
```

Example prompt: I'm about to add a new USDC settlement rail to my live x402-metered API and I'm worried about CDN edge caches serving stale 402 payment terms — can you run the new-rail rollout decision procedure and tell me if I should proceed or roll back?

## When to prefer this

Choose this endpoint when you are a merchant or operator adding a new settlement rail to a live x402-metered API and need a structured go/no-go decision that explicitly addresses CDN stale-challenge propagation delays, cross-region 402 verification, and rollback criteria — especially if you have previously encountered CDN cache problems after announcing a new rail. Prefer over generic rollout guides when you need an x402-specific, agent-callable decision procedure with explicit PASS/ROLLBACK output.

## Known failure modes

- Missing required 'type' or 'method' input fields returns a validation error
- Invalid method values (outside GET/HEAD/DELETE) are rejected by schema
- LLM generation failure may return ok:false with no procedure text
- Network timeout to the k2so-8080.on.ascii.dev host results in no response
- Payment failure (insufficient USDC or stale 402 challenge) blocks paid response; use meta=1 for free metadata only

## How this service works

Decision procedure for a merchant adding a new settlement rail to a live x402-metered endpoint. Covers the CDN stale-challenge problem (edge caches serving old 402 payment terms), pre-flight capability evidence for the new rail, staged rollout with old rail kept active, cross-region 402 challenge verification, and explicit rollback criteria. Output: PASS with rollout window or ROLLBACK with evidence. Built for operators who have been burned debugging stale CDN caches after announcing a new rail

## Output

A structured response containing a PASS with rollout window or ROLLBACK with supporting evidence, plus a detailed decision procedure prose brief covering CDN stale-challenge handling, pre-flight capability evidence for the new rail, staged rollout guidance, and explicit rollback criteria. Includes generation timestamp, source model, and service metadata.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "x402 endpoint new-rail rollout with CDN stale-challenge handling paid response",
     "$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"
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-new-rail-rollout-decision-procedure-with-cdn-stale-challenge-c333bf1e/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)