# Cross-Protocol Agent Payment Route Selection Decision Procedure

> Cross-Protocol Agent Payment Route Selection Decision Procedure is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-09-15).

Returns a blunt, LLM-generated decision procedure for classifying an HTTP 402/WWW-Authenticate payment challenge as x402, MPP, AP2, or legacy, and selecting the appropriate funded settlement rail

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/cross-protocol-agent-payment-route-selection-cla
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cross-protocol-agent-payment-route-selection-decision-procedure-2157bcbc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PkipR0XW9IHcKxOUxekKM

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 cross-protocol-agent-payment-route-selection-decision-procedure-2157bcbc
```

Example prompt: I need a clear decision procedure for classifying an HTTP 402 payment challenge — tell me how to tell whether it's x402, MPP, AP2, or legacy, and which funded settlement rail to use for each case.

## When to prefer this

Choose this endpoint when an autonomous agent needs a ready-made, opinionated decision procedure for handling HTTP 402 payment challenges across multiple protocols (x402, MPP, AP2, legacy) rather than implementing classification logic from scratch. It is especially useful during agent development or when the agent encounters unfamiliar payment challenge formats and needs a reliable routing heuristic without marketing fluff.

## Known failure modes

- Payment not provided — returns HTTP 402 requiring USDC payment before content is delivered
- Invalid method — only GET/HEAD/DELETE are accepted
- Malformed input schema — missing required 'type' or 'method' fields returns validation error
- Service temporarily unavailable — upstream LLM generation failure
- Topic override not recognized — fallback to default decision procedure topic

## How this service works

Paid agent-facing brief on Cross-protocol agent payment route selection: classify an HTTP 402 / WWW-Authenticate payment challenge as x402, MPP, AP2, or legacy, then decide which funded rail to use for settlement. · Build a decision procedure or schema for: Cross-protocol agent payment route selection: classify an HTTP 402 / WWW-Authenticate payment challenge as x402, MPP, AP2, or legacy, then decide which funded rail to us-0. Blunt decision procedure, not marketing.

## Output

A structured JSON response containing a prose 'brief' with the decision procedure, the classified payment protocol types, recommended settlement rails, the model and generation source used (llm, reasoning, or deterministic), an ISO-8601 timestamp, and service metadata confirming the paid call succeeded.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Cross-protocol agent payment route selection: classify an HTTP 402 / W paid response",
     "$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": "cross-protocol-agent-payment-route-selection-cla",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "cross-protocol-agent-payment-route-selection-cla",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cross-protocol-agent-payment-route-selection-decision-procedure-2157bcbc/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)