# x402 Pay-Per-Call Inference Endpoint Selection and Cost Normalization

> x402 Pay-Per-Call Inference Endpoint Selection and Cost Normalization 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 2026-10-16).

Returns a decision procedure for agents on how to select and cost-normalize x402 pay-per-call inference endpoints across DePIN/x402 inference rails, including per-token cost normalization and fallback laddering.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/x402-pay-per-call-inference-endpoint-selection-a?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-pay-per-call-inference-endpoint-selection-and-cost-normalization-fc4d763c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2WywIa0jyNDme1AEhdfCc

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-pay-per-call-inference-endpoint-selection-and-cost-normalization-fc4d763c
```

Example prompt: Give me the full decision procedure for selecting and cost-normalizing x402 pay-per-call inference endpoints — I need the per-token cost comparison logic, fallback ladder, and failure modes so my agent knows when to switch rails.

## When to prefer this

Use this endpoint when an agent needs a structured, actionable decision procedure for navigating x402 inference rails — specifically when cost normalization across DePIN providers, fallback ordering, or per-token spend thresholds are required. Prefer over generic LLM prompting when a pre-built, paid-verified procedure with defined failure modes is needed. Not suitable for real-time price feeds or live endpoint health checks.

## Known failure modes

- Endpoint returns non-payment error if meta=1 is not set and payment is not provided
- Topic override may produce off-scope procedure if topic string is malformed
- LLM generation source may produce non-deterministic output across calls
- Service may return ok:false in result object if handler fails internally
- No input schema validation on topic field — arbitrary strings accepted

## How this service works

Paid agent-facing brief on x402 pay-per-call inference endpoint selection and cost normalization procedure for agents (DePIN/x402 inference rails, per-token cost, fallback ladder) · Build a decision procedure or schema for: x402 pay-per-call inference endpoint selection and cost normalization procedure for agents (DePIN/x402 inference rails, per-token cost, fallback ladder). Include inputs, thresholds, failure modes. Falsif-0. Blunt decision procedure, not marketing.

## Output

A structured decision procedure brief including: prose guidance for agents on selecting x402 inference endpoints, per-token cost normalization methodology, a ranked fallback ladder for DePIN/x402 inference rails, defined cost thresholds, failure modes and their handling, and metadata including generation source (llm/reasoning/deterministic) and ISO-8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "x402 pay-per-call inference endpoint selection and cost normalization paid response",
     "$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/x402-pay-per-call-inference-endpoint-selection-and-cost-normalization-fc4d763c/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)