# Saymon RU Data API — Claude Opus 5 LLM Chat

> Saymon RU Data API — Claude Opus 5 LLM Chat is a paid API for AI agents from payforapi.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Provides pay-per-call access to Anthropic Claude Opus 5 via an OpenAI-compatible chat endpoint, accepting up to 40K input tokens and returning up to 4K output tokens for $0.05 per call.

## Facts

- Endpoint: POST https://payforapi.com/v1/chat/claude-opus-5
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saymon-ru-data-api-claude-opus-5-llm-chat-288e5f4d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cT44udi6H_7EOOWQGpOQI

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 saymon-ru-data-api-claude-opus-5-llm-chat-288e5f4d -d '<json body>'
```

Example prompt: Can you use Claude Opus 5 to write me a detailed 3-paragraph explanation of how EIP-3009 meta-transactions work for USDC, keeping the response under 4096 tokens?

## When to prefer this

Choose this endpoint when you need access to Anthropic's Claude Opus 5 — one of the highest-capability LLMs available — on a pay-per-call basis without a subscription, particularly for agent pipelines that require top-tier reasoning, complex instruction-following, or nuanced text generation. Prefer it over cheaper tiers when task quality matters most, and over self-hosted alternatives when you want zero infrastructure overhead. The x402 micropayment model makes it ideal for sporadic or low-volume agent calls.

## Known failure modes

- Input exceeds ~40K token limit — request rejected or truncated
- max_tokens set above 4096 — validation error
- Malformed messages array (missing role or content fields) — schema validation error
- Payment failure or insufficient USDC balance — 402 Payment Required
- Model temporarily unavailable — upstream provider error
- Temperature out of valid range — parameter error

## How this service works

PAYFORAPI.com — окно между ру-рынком и глобальным x402. Глобальный провайдер: твой эндпоинт платят агенты из СНГ. Ру-провайдер: твой сервис — на мировой витрине. Локализация, продвижение, платежи USDC — наша работа.

## Output

Returns an OpenAI-compatible JSON response containing the assistant's generated text message, token usage breakdown (prompt, completion, total tokens), a finish reason (e.g. 'stop'), message ID, and the model identifier. The content field holds the raw text output from Claude Opus 5.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "id": "msg_abc",
  "model": "cc/claude-opus-5",
  "usage": {
   "total_tokens": 9095,
   "prompt_tokens": 9050,
   "completion_tokens": 45
  },
  "choices": [
   {
    "index": 0,
    "message": {
     "role": "assistant",
     "content": "EIP-3009 lets a user authorize a transfer of USDC with a signed message..."
    },
    "finish_reason": "stop"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saymon-ru-data-api-claude-opus-5-llm-chat-288e5f4d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payforapi.com](https://www.zero.xyz/host/payforapi.com/llms.txt)