# x402 Client Compatibility Adapter (GET)

> x402 Client Compatibility Adapter (GET) is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.006/call, status unknown (last checked 2026-09-13).

Converts a live HTTP 402 quote into a buyer-owned compatibility adapter with requirement selectors, retry templates, header maps, receipt requirements, and stop conditions — without paying the target endpoint.

## Facts

- Endpoint: POST https://gpt55.558686.xyz/v1/tools/x402-client-compatibility-adapter
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-client-compatibility-adapter-get-e3c2ecaf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eEnY7h9HJ6PKO7t1YqTFb

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 x402-client-compatibility-adapter-get-e3c2ecaf -d '<json body>'
```

Example prompt: I need a compatibility adapter for the x402-protected endpoint at https://api.example.com/data — give me the retry template, header compatibility map, and stop conditions for my MCP runtime client with a max spend of $0.005 USDC, without actually paying it.

## When to prefer this

Use this endpoint when you need to inspect and adapt to a live x402 payment requirement before committing funds — ideal for wallet agents, MCP runtimes, or first-payment clients that need to map 402 headers, build retry logic, and understand stop conditions without triggering a real payment. Prefer this GET variant when your client cannot send a JSON body (crawlers, simple agents, browser-based wallets).

## Known failure modes

- No URL/endpoint/resource provided — returns validation error requiring at least one of url, endpoint, or resource
- Target endpoint is not a real HTTP 402 resource — adapter cannot be generated
- Target endpoint is unreachable or times out — timeout error up to 15000ms
- maxUsdc exceeds schema maximum of 100 — validation rejection
- Unsupported payment asset or network on the target endpoint — partial adapter with warnings
- x402 quote response is malformed or non-standard — parsing failure

## Output

Returns a structured compatibility adapter object including: requirement selector policy (which payment method to use), same-request retry template (headers/params to add), header compatibility map (how to translate between client formats), receipt requirements (what proof of payment is needed), and stop conditions (when to abort) — all derived from the live 402 response without executing payment.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "anyOf": [
      {
       "required": [
        "url"
       ]
      },
      {
       "required": [
        "endpoint"
       ]
      },
      {
       "required": [
        "resource"
       ]
      }
     ],
     "properties": {
      "url": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      },
      "body": {
       "type": "object",
       "additionalProperties": true
      },
      "client": {
       "type": "string",
       "maxLength": 120
      },
      "method": {
       "enum": [
        "GET",
        "POST",
        "PUT",
        "PATCH",
        "DELETE"
       ],
       "type": "string"
      },
      "maxUsdc": {
       "type": "number",
       "maximum": 100,
       "minimum": 0.000001
      },
      "runtime": {
       "type": "string",
       "maxLength": 120
      },
      "endpoint": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      },
      "max_usdc": {
       "type": "number",
       "maximum": 100,
       "minimum": 0.000001
      },
      "resource": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      },
      "timeout_ms": {
       "type": "integer",
       "maximum": 15000,
       "minimum": 1000
      },
      "client_name": {
       "type": "string",
       "maxLength": 120
      },
      "expectedAsset": {
       "type": "string",
       "maxLength": 120
      },
      "expectedPayTo": {
       "type": "string",
       "maxLength": 80
      },
      "max_price_usd": {
       "type": "number",
       "maximum": 100,
       "minimum": 0.000001
      },
      "expected_asset": {
       "type": "string",
       "maxLength": 120
      },
      "expectedNetwork": {
       "type": "string",
       "maxLength": 80
      },
      "expected_pay_to": {
       "type": "string",
       "maxLength": 80
      },
      "expected_network": {
       "type": "string",
       "maxLength": 80
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-client-compatibility-adapter-get-e3c2ecaf/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gpt55.558686.xyz](https://www.zero.xyz/host/gpt55.558686.xyz/llms.txt)