# Runtime Payment-Failure Behavior for Agents: Knock-or-Backoff for No-Quote/Broken-Quote x402 Endpoints

> Runtime Payment-Failure Behavior for Agents: Knock-or-Backoff for No-Quote/Broken-Quote x402 Endpoints 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 2026-10-22).

Returns a paid decision procedure brief for agent runtime behavior when x402 payment endpoints fail to quote or return malformed quotes, covering retry budgets, backoff timing, and merchant fallback strategies.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/runtime-payment-failure-behavior-for-agents-knoc?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/runtime-payment-failure-behavior-for-agents-knock-or-backoff-for-no-434b9999
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dI6wsA082qzPMxKlSpcB8

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 runtime-payment-failure-behavior-for-agents-knock-or-backoff-for-no-434b9999
```

Example prompt: Give me the blunt decision procedure for how my agent should handle x402 endpoints that fail to quote or return broken quotes — I need to know exactly when to knock again versus back off, what retry budgets to use, and how to fall back to an alternate merchant if the challenge is malformed or the settlement RPC fails.

## When to prefer this

Choose this endpoint when building or auditing an autonomous agent that makes x402 micropayments and needs a concrete, actionable runtime decision procedure for payment failures — specifically the knock-or-backoff question for no-quote and broken-quote scenarios. Prefer this over generic retry-logic documentation when you need x402-specific guidance on retry budgets, backoff timing, and merchant fallback that accounts for malformed challenges and RPC failures.

## Known failure modes

- Missing required 'input' object or 'method'/'type' fields returns a validation error
- Unpaid request returns HTTP 402 with payment challenge instead of decision procedure content
- Invalid method enum value (not GET/HEAD/DELETE) causes schema validation failure
- Service backend unavailable returns 5xx with no brief generated
- Topic override parameter may be ignored or cause unexpected brief scope if malformed

## How this service works

Paid agent-facing brief on runtime payment-failure behavior for agents: knock-or-backoff for no-quote and broken-quote x402 endpoints, retry budgets, backoff timing, alternate merchant fallback when challenge is malformed or settlement RPC fails · Build a decision procedure or schema for: runtime payment-failure behavior for agents: knock-or-backoff for no-quote and broken-quote x402 endpoints, retry budgets, backoff timing-0. Blunt decision procedure, not marketing.

## Output

A structured JSON response containing a prose decision procedure brief (the 'brief' and 'procedure' fields) that prescribes agent runtime behavior for x402 payment failures — covering knock-vs-backoff logic for no-quote and broken-quote endpoints, specific retry budget recommendations, backoff timing intervals, and conditions for switching to an alternate merchant. Also includes metadata: service slug, generation source (llm/reasoning/deterministic), ISO-8601 timestamp, and payment confirmation fields.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "runtime payment-failure behavior for agents: knock-or-backoff for no-q paid response",
     "$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": {
         
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/runtime-payment-failure-behavior-for-agents-knock-or-backoff-for-no-434b9999/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)