# Claude Opus 4.5 via x402 Gateway

> Claude Opus 4.5 via x402 Gateway is a paid API for AI agents from x402-gateway-production.up.railway.app, paid per call via x402, $0.09/call, status unknown (last checked 2026-09-13).

Calls Anthropic's Claude Opus 4.5 (previous-gen flagship) for advanced reasoning and creative writing tasks via a pay-per-call x402 gateway

## Facts

- Endpoint: POST https://x402-gateway-production.up.railway.app/api/llm/claude-opus-4.5
- Price: $0.09/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-gateway-production-up-railway-app-7c7e0ece
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sQclIL6-mynVXWhF27-fj

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-gateway-production-up-railway-app-7c7e0ece -d '<json body>'
```

Example prompt: Write me a short creative story about a robot learning to appreciate music — use Claude Opus for the rich, nuanced prose quality.

## When to prefer this

Choose this endpoint when you need Anthropic's Claude Opus 4.5 model specifically — known for strong creative writing quality, nuanced reasoning, and a large context window — and want a simple pay-per-call pricing model ($0.09 USDC) without managing Anthropic API keys or subscriptions. Prefer over lighter Claude models (Haiku, Sonnet) when output quality and depth matter more than speed or cost.

## Known failure modes

- Payment failure if USDC balance insufficient for $0.09 per-call fee
- Rate limiting or quota exceeded on the gateway
- Malformed messages array causing a 400 bad request
- Model unavailable or upstream Anthropic API outage returning 503
- Token limit exceeded if prompt is excessively long
- Invalid role values in the messages array

## How this service works

Anthropic's previous-gen Opus — strong reasoning and creative writing, large context window

## Output

Returns a JSON object containing the full generated text content from Claude Opus 4.5, along with model metadata (model name: anthropic/claude-4.5-opus-20251124), token usage breakdown (prompt tokens, completion tokens, total tokens), and cost details including upstream inference cost split between prompt and completion. The content field contains the full AI-generated response.

## Example request

```json
{
 "messages": [
  {
   "role": "user",
   "content": "Write a short creative story about a robot learning to appreciate music."
  }
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-gateway-production-up-railway-app-7c7e0ece/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-gateway-production.up.railway.app](https://www.zero.xyz/host/x402-gateway-production.up.railway.app/llms.txt)