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Agent402 Pro Messages — Pay-Per-Call AI Inference via x402
x402
Agent402 Pro Messages — Pay-Per-Call AI Inference via x402 is a paid API for AI agents from agent402.tools, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).
Runs an Anthropic-compatible Messages API call (Claude models) paid per-request in USDC via x402, with no signup or API keys required — the wallet is the identity.
Price / call$0.1
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/pro and pay $0.10 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 48,000 input chars and 4096 output tokens; streaming supported.
Output
An Anthropic Messages API-compatible JSON object containing the assistant role response, content blocks (text and/or tool_use), the model name, stop_reason (end_turn, tool_use, max_tokens, etc.), and token usage counts for input and output. When streaming is enabled, returns Anthropic SSE events (message_start through message_stop).
Example use cases
Wallet-authenticated agent reasoning
“I want my AI agent to call Claude to reason through a multi-step problem without me setting up any API keys — just pay per call from the wallet. Use anthropic/claude-sonnet-5, set max_tokens to 1024, and pass my system prompt about being a financial analyst.”
Zero-data-retention LLM call
“Run a Claude inference call with zero-data-retention providers only — I'm processing sensitive documents and can't have the provider store anything. Use the zdr flag, model auto, max_tokens 2048, and stream the response back.”
Tool-augmented agent with x402 billing
“My agent needs to call Claude with a custom tool definition for web search — pass the tool schema in the tools array, use anthropic/claude-opus-4, max_tokens 4096, and have the response stream back so I can show the thinking steps as they arrive.”
Technical details
Endpoint
POSThttps://agent402.tools/v1/pro/messagesWhen to prefer
Choose this endpoint when you need Claude inference paid micropayment-style (USDC per call) without any account signup, API key management, or subscription — ideal for AI agents that self-fund via crypto wallets, workflows requiring zero-data-retention compliance, or developers building x402-native agentic pipelines. Prefer over standard Anthropic or OpenRouter direct access when wallet-as-identity authentication and on-chain per-call billing are required.
Side effects
- Payment failure (402) if wallet has insufficient USDC or x402 handshake fails
- Model not allowlisted for the tier — returns error indicating model restriction
- max_tokens exceeds tier output cap — clamped silently or rejected
- Malformed messages array (missing role or content) causes 400 validation error
- Unsupported model ID string causes routing failure
- Stream connection drop mid-response leaves partial SSE event buffer
- ZDR flag set but no ZDR-compliant provider available for requested model
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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