# WebRef HTTP Method Safety & Idempotency Lookup

> WebRef HTTP Method Safety & Idempotency Lookup is a paid API for AI agents from webref.johnaio281.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-22).

Returns safety, idempotency, and semantic metadata for a given HTTP request method (GET, HEAD, or DELETE)

## Facts

- Endpoint: GET https://webref.johnaio281.workers.dev/api/web/http_method?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/webref-http-method-safety-idempotency-lookup-47a13eee
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4PUOxiq8v5BqF6zMFH9M-

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 webref-http-method-safety-idempotency-lookup-47a13eee
```

Example prompt: Is the HTTP DELETE method safe to retry automatically, and is it idempotent? Look up its semantics so I know how to handle failures in my API client.

## When to prefer this

Choose this endpoint when an AI agent or API client needs authoritative, machine-readable lookup of HTTP method safety and idempotency properties at runtime — especially when implementing retry logic, building documentation, or making decisions about whether a failed request can be safely retried. Covers GET, HEAD, and DELETE. Use sibling WebRef endpoints for HTTP status codes, MIME types, or time/deadline arithmetic.

## Known failure modes

- Unsupported method enum value (only GET, HEAD, DELETE accepted) results in validation error
- Missing required 'method' field returns an input schema error
- Missing required 'type' field (must be 'http') returns an error
- Network timeout to workers.dev endpoint
- Payment failure via x402 or MPP prevents access

## How this service works

Web standards and time reference for AI agents: HTTP status codes with what the client should do, retry semantics, MIME types and content-type matching, request-method safety and idempotency, plus deadline arithmetic - time until a moment, weekday and business-day checks, duration conversion and Unix timestamps. Pay per call in USDC on Base via x402 or USDC on Tempo via MPP. No signup, no API key, no KYC.

## Output

Returns structured metadata about the specified HTTP method, including whether it is safe (has no observable side effects), whether it is idempotent (repeating the call produces the same result), semantic description of the method, and guidance on client retry behavior.

## 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",
     "method": {
      "def": {
       "type": "string"
      },
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/webref-http-method-safety-idempotency-lookup-47a13eee/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from webref.johnaio281.workers.dev](https://www.zero.xyz/host/webref.johnaio281.workers.dev/llms.txt)