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Agent402 Premium AI Messages (x402 Pay-Per-Call LLM Inference)
x402
Agent402 Premium AI Messages (x402 Pay-Per-Call LLM Inference) is a paid API for AI agents from agent402.tools, paid per call via x402, $0.5/call, status unknown (last checked 2026-09-15).
Proxies Anthropic-compatible chat completion requests to frontier LLMs, billed per call in USDC via x402 with no API key required
Price / call$0.5
Success—
StatusUnknown
How this service works
Anthropic Messages API over x402 - point the Anthropic SDK (or Claude Code / the Agent SDK) at base_url https://agent402.tools/v1/premium and pay $0.50 per call in USDC, no API key, no signup. Same models, caps and price as this tier's /chat/completions route; any model here is served through the Messages wire (Claude natively, others translated). Up to 200,000 input chars and 8192 output tokens; streaming supported.
Output
Returns an Anthropic-format message object containing the assistant role, one or more content blocks (text and/or tool_use), the stop_reason (end_turn, tool_use, max_tokens, etc.), the resolved model name, and input/output token counts. When streaming is enabled, delivers Anthropic SSE events (message_start through message_stop).
Example use cases
Autonomous agent self-funding LLM calls
“I want my AI agent to call Claude Sonnet directly and pay for each inference with USDC from its wallet — no API keys, just send the messages array and let x402 handle the billing. Use anthropic/claude-sonnet-5 with max_tokens 512.”
Zero-data-retention compliance query
“Run this legal document summary through Claude with zero-data-retention mode enabled so none of my text is stored anywhere — send it as the user message, use anthropic/claude-sonnet-5, and cap output at 2048 tokens.”
Extended thinking for complex reasoning
“I need Claude to deeply reason through this math proof step by step — enable extended thinking with a budget of 5000 tokens, use the auto model, and give me a max of 4096 output tokens for the response.”
Technical details
Endpoint
POSThttps://agent402.tools/v1/premium/messagesWhen to prefer
Choose this endpoint when you need LLM inference (especially Claude-family models) without managing API keys or subscriptions — ideal for AI agents that self-fund via a USDC wallet, scenarios requiring anonymous or pseudonymous access (wallet-as-identity), compliance use cases needing zero-data-retention, or when building on the x402 / MPP payment standard. Prefer alternatives (direct Anthropic API, OpenAI) if you already have managed credentials, need non-Claude models not on the allowlist, or cannot handle x402 payment flows.
Side effects
- 402 Payment Required if wallet has insufficient USDC balance
- Model ID not allowlisted for the caller's tier returns an error
- max_tokens exceeds tier output cap and gets clamped or rejected
- Malformed messages array (wrong role sequence) causes 400 bad request
- Zero-data-retention requested but no ZDR-compliant provider available for the selected model
- Streaming connection dropped mid-response leaves partial SSE stream
- Tool schema validation failure if client-supplied tools have invalid input_schema
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| zdr | boolean | Optional - zero-data-retention providers only |
| model | string | Model id (OpenRouter naming, e.g. anthropic/claude-sonnet-5) - allowlisted per tier; omit (or "auto") on the auto tier |
| tools | array | Optional client tools {name, description, input_schema}; server/built-in tools are not served |
| stream | boolean | Anthropic SSE (message_start … message_stop) |
| system | string | Optional system prompt (string or text blocks) |
| messages | array | Anthropic messages: {role: user|assistant, content: string | [text|image|tool_use|tool_result blocks]} |
| thinking | object | Optional {type:"enabled", budget_tokens} | {type:"adaptive"} | {type:"disabled"} - thinking tokens are output tokens |
| max_tokens | integer | Required by the Messages API; clamped to the tier's output cap |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "msg_…",
"role": "assistant",
"type": "message",
"model": "anthropic/claude-sonnet-5",
"usage": {
"input_tokens": 14,
"output_tokens": 18
},
"content": [
{
"text": "x402 is an HTTP-native way for agents to pay per request with USDC.",
"type": "text"
}
],
"stop_reason": "end_turn"
}
}Tags
x402
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