# K-2SO x402 Pay-Per-Call Inference Endpoint Selection & Cost Normalization

> K-2SO x402 Pay-Per-Call Inference Endpoint Selection & Cost Normalization is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Returns a paid AI-generated decision procedure (prose brief) guiding an autonomous agent on how to select and cost-normalize x402 pay-per-call inference endpoints

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/x402-pay-per-call-inference-endpoint-selection-a
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/k-2so-x402-pay-per-call-inference-endpoint-selection-cost-normalization-ec9306b5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KsQNVtMNdJqWzNFVkgb46

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 k-2so-x402-pay-per-call-inference-endpoint-selection-cost-normalization-ec9306b5
```

Example prompt: Give me a decision procedure for selecting the right x402 pay-per-call inference endpoint — I need plain-prose guidance on how to evaluate and cost-normalize options, specifically for inference use cases.

## When to prefer this

Choose this endpoint when an autonomous agent needs structured, prose-form guidance on how to evaluate and select among multiple x402 pay-per-call inference endpoints — particularly when cost normalization across providers is required. Prefer it over generic LLM prompts when you want a curated, merchant-vetted decision procedure specifically scoped to the x402 micropayment ecosystem on Base. It is especially useful for agent orchestration layers that need a repeatable, auditable selection logic rather than ad-hoc reasoning.

## Known failure modes

- HTTP 402 returned if USDC payment not yet settled — agent must pay exact amount and retry with PAYMENT-SIGNATURE header
- Invalid method (POST/PUT/PATCH) returns an error — only GET/HEAD/DELETE are accepted
- Malformed topic override may produce off-target decision procedure
- If meta=1 is not set and payment is absent, no result content is returned
- Network or agent merchant downtime on k2so.wrong.systems may cause timeouts

## 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 JSON object containing a plain-prose decision procedure brief (120+ words) for selecting and cost-normalizing x402 pay-per-call inference endpoints, including the service slug, topic, the model that generated it, an ISO-8601 timestamp, and a generationSource enum indicating whether the procedure came from an LLM, reasoning engine, or deterministic logic. The 'brief' and 'procedure' fields carry the actionable agent guidance.

## 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)
```

## 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": "x402-pay-per-call-inference-endpoint-selection-a",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "x402-pay-per-call-inference-endpoint-selection-a",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/k-2so-x402-pay-per-call-inference-endpoint-selection-cost-normalization-ec9306b5/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)