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Model Access Gateway – Claude Opus 5 Chat Completions (x402, USDC)
x402
Model Access Gateway – Claude Opus 5 Chat Completions (x402, USDC) is a paid API for AI agents from modelaccessgateway.com, paid per call via x402, $0.0014/call, status unknown (last checked 2026-10-16).
Runs OpenAI-compatible chat completions against Claude Opus 5 via a pay-per-call API billed in USDC on Base using the x402 protocol — no account or API key required.
Price / call$0.0014
Success—
StatusUnknown
How this service works
LLM inference API: OpenAI-compatible chat completions for 136 AI models (Claude, GPT, Gemini, Grok, DeepSeek, Qwen, Kimi, GLM), paid per call in USDC on Base with x402. No account, no API key, automatic refund if the model fails.
Output
Returns an OpenAI-compatible chat.completion JSON object containing the assistant's message content, finish reason (e.g. 'stop'), token usage breakdown (prompt, completion, total), model name, completion ID, and creation timestamp. Streaming mode delivers server-sent events incrementally.
Example use cases
Autonomous agent complex reasoning task
“I need you to use Claude Opus 5 to reason through this multi-step business strategy problem and give me a detailed structured breakdown — pay per call with USDC, stream the answer, and allow up to 12000 tokens.”
Anonymous LLM call from a script
“Call Claude Opus 5 with this system prompt and user message without me having to set up any API key or account — just pay with USDC on Base and return the full completion.”
Tool-use request with structured output
“Send this function-calling request to Claude Opus 5 with the tool definitions I've provided, use JSON response format, temperature 0, and max 4096 tokens — I want the model to invoke the right tool based on the user message.”
Technical details
Endpoint
POSThttps://modelaccessgateway.com/llm/claude-opus-5?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need Claude Opus 5 specifically (Anthropic's most capable model) and want pay-per-call pricing in USDC with no account signup, API key management, or subscription. Ideal for autonomous agents that need to make one-off LLM calls, developers prototyping without committing to a provider, or workflows that require the automatic refund guarantee on model failure. Prefer over direct Anthropic API when you need anonymous/keyless access or are already operating in a crypto-native payment environment using x402.
Side effects
- Insufficient USDC balance — payment rejected before inference begins
- Model unavailable or overloaded — automatic refund issued, no charge
- Invalid messages array (missing required role field) — 422 validation error
- max_tokens exceeds 16384 limit — request rejected
- Temperature outside 0–2 range — validation error
- Network timeout on streaming response — partial output, no refund guarantee
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| model | string | Optional: fixed by the route (anthropic/claude-opus-5) |
| tools | array | |
| stream | boolean | true: server-sent events after payment |
| messages | array | |
| max_tokens | integer | Optional, default 4096 |
| temperature | number | |
| response_format | object |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "chatcmpl-7f3c2a91",
"model": "anthropic/claude-opus-5",
"usage": {
"total_tokens": 10,
"prompt_tokens": 9,
"completion_tokens": 1
},
"object": "chat.completion",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "OK"
},
"finish_reason": "stop"
}
],
"created": 1791979200
}
}Tags
x402
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