# Saylor Innovations Guide Library – x402 Client Spend Limits & Retries

> Saylor Innovations Guide Library – x402 Client Spend Limits & Retries is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).

Returns a guide document explaining how to build a safe x402 payment client with per-payment and daily spend caps, host and payee allowlists, and retry logic for ambiguous settlement scenarios

## Facts

- Endpoint: GET https://saylorinnovations.com/api/kb/x402-client-spend-limits-and-retries?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-guide-library-x402-client-spend-limits-retries-50072654
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_i1I73mTwrbsrd14w3gqbL

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 saylor-innovations-guide-library-x402-client-spend-limits-retries-50072654
```

Example prompt: Pull up the Saylor Innovations guide on building a safe x402 client — I need the section covering per-payment and daily spend caps, host and payee allowlists, and how to handle retries when settlement is ambiguous.

## When to prefer this

Choose this endpoint when you need authoritative, structured guidance specifically on implementing x402 client-side spend controls (per-payment caps, daily caps), allowlisting (hosts and payees), and retry safety (identical-header retries after ambiguous settlement). Prefer this over general web search when you want a curated, consistently formatted document from a dedicated x402 knowledge base.

## Known failure modes

- 404 if the guide record is not found at this path
- 402 Payment Required if the $0.01 USDC payment header is missing or invalid
- Non-JSON or malformed response if the knowledge base is temporarily unavailable
- Empty or truncated body field if the guide content has not been fully indexed

## How this service works

Build a safe x402 client - per-payment and daily caps, host and payee allowlists, identical-header retries after ambiguous settlement and payment receipts

## Output

A JSON object containing the guide's ID, title, category, full body text (the actual guide content on x402 client spend limits, allowlists, and retry logic), an optional price field, and a license identifier.

## 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"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "id",
      "t",
      "c",
      "body"
     ],
     "properties": {
      "c": {
       "type": "string",
       "description": "Category of the guide"
      },
      "t": {
       "type": "string",
       "description": "Title of the guide"
      },
      "id": {
       "type": "string",
       "description": "Identifier of the record"
      },
      "body": {
       "type": "string",
       "description": "Main body text"
      },
      "price": {
       "type": [
        "number",
        "null"
       ],
       "description": "Price"
      },
      "license": {
       "type": "string",
       "description": "License identifier"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-guide-library-x402-client-spend-limits-retries-50072654/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)