# Per-Rail Fee and Settlement-Speed Ranking Procedure for Agent x402

> Per-Rail Fee and Settlement-Speed Ranking Procedure for Agent x402 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 2026-09-13).

Returns a deterministic decision procedure brief that ranks blockchain settlement rails by fee and speed observations to guide an agent's next x402 payment settlement choice.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/per-rail-fee-and-settlement-speed-ranking-proced
- 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/per-rail-fee-and-settlement-speed-ranking-procedure-for-agent-x402-7285e36f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Y4zSEqCvc-Ap5r_1PlgKf

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 per-rail-fee-and-settlement-speed-ranking-procedure-for-agent-x402-7285e36f
```

Example prompt: I need to figure out which blockchain settlement rail to use for my next x402 payment — can you fetch the ranking procedure that compares rails by fee and settlement speed, including how to normalize gas vs priority fees and handle stale observations?

## When to prefer this

Use this endpoint when an agent needs a structured, authoritative decision procedure for ranking payment rails before executing an x402 settlement — specifically when the agent must compare rails with heterogeneous fee units (gas vs flat fee vs priority fee) and needs normalization logic and staleness handling baked in. Prefer this over ad-hoc fee lookups when you need a complete, deterministic ranked order with tie-breaking rules rather than raw fee data alone. Distinct from route selection endpoints that assume a rail is already chosen.

## Known failure modes

- Payment not received or insufficient — endpoint returns 402 with payment instructions
- Invalid or missing required input fields — returns validation error
- Stale or unavailable rail data — procedure may note limitations in coverage
- LLM/reasoning generation failure — generationSource may indicate fallback or error in result object
- Network timeout on the ascii.dev host — transient 5xx error

## How this service works

Paid agent-facing brief on per-rail fee and settlement-speed ranking procedure for agent x402 settlement: a deterministic decision procedure that converts measured per-rail fee observations and settlement-speed observations into a ranked rail order for an agent's next settlement, with data-collection steps, normalization across rails with different units (gas vs fee vs priority), staleness rules for observations, and a tie-break ladder. Distinct from route selection (which picks a rail given an

## Output

A paid prose brief (decision procedure) describing: data-collection steps for per-rail fee and settlement-speed observations, normalization methodology across rails with different units (gas, fee, priority), staleness rules for when observations expire, and a tie-break ladder — returned as a structured JSON object with an `ok` flag, the brief text, generation source, timestamp, and service metadata.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "per-rail fee and settlement-speed ranking procedure for agent x402 set paid response",
     "$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/per-rail-fee-and-settlement-speed-ranking-procedure-for-agent-x402-7285e36f/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)