# Multi-Chain Onchain Data Sourcing and Provider Selection Procedure

> Multi-Chain Onchain Data Sourcing and Provider Selection Procedure 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 structured decision procedure for AI agents on how to select and route onchain data queries across chains, providers, and indexing layers.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/multi-chain-onchain-data-sourcing-and-provider-s?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/multi-chain-onchain-data-sourcing-and-provider-selection-procedure-e6921562
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_74uJQ0ykPh02mKmAA2Vji

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 multi-chain-onchain-data-sourcing-and-provider-selection-procedure-e6921562
```

Example prompt: I need to query token balances and decoded contract events across Ethereum, Base, and Arbitrum — can you give me a decision procedure for which onchain data provider to use for each query type, including how to handle rate limits and confirm finality before acting?

## When to prefer this

Choose this endpoint when an AI agent needs structured, payable decision-procedure guidance for routing onchain data queries across multiple chains and providers — especially when the agent must balance cost, rate limits, finality requirements, and cross-chain coverage in a single coherent workflow. Prefer this over raw provider documentation when you need opinionated, agent-ready routing logic with built-in evidence logging schema rather than raw API specs.

## Known failure modes

- Payment not provided — returns 402 with payment details rather than the procedure
- Invalid or unsupported topic override — may return generic procedure without topic-specific guidance
- Rate limits on the upstream service — may return error or degraded response
- Malformed input schema — missing required 'type' or 'method' fields returns validation error
- Service unavailability — K-2SO host unreachable, returns network or 5xx error

## How this service works

Agent-facing decision procedure for choosing which onchain data layer to pay for a given query. Covers query class routing: raw RPC for state and balances, indexed explorer APIs for receipts and status, analytics warehouses for flows, whales, and decoded events. Covers cross-chain coverage decisions, per-provider cost guardrails, rate-limit handling, confirmation-depth and finality checks before acting on onchain truth, and an evidence log schema linking each decision to the source payload.

## Output

A paid response containing prose decision-procedure guidance (the 'brief' field), covering query class routing, provider selection, cross-chain coverage, cost guardrails, rate-limit handling, confirmation-depth checks, and an evidence log schema. Also includes metadata such as generation source (llm/reasoning/deterministic), topic, service slug, and ISO-8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Multi-chain onchain data sourcing and provider selection procedure paid response",
     "$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": {
         "typ
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/multi-chain-onchain-data-sourcing-and-provider-selection-procedure-e6921562/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)