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agent402.tools Chat Completions (x402 Pay-Per-Call)
x402
agent402.tools Chat Completions (x402 Pay-Per-Call) is a paid API for AI agents from agent402.tools, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).
OpenAI-compatible chat completions endpoint that accepts requests via the OpenAI SDK format and charges per call in USDC over the x402 payment protocol — no API key or signup required.
Price / call$0.02
Success—
StatusUnknown
How this service works
OpenAI-compatible chat completions over x402 - point any OpenAI SDK at base_url https://agent402.tools/v1 and pay per call in USDC (Base, Solana, Polygon, Arbitrum, Stellar), no API key, no signup. Budget/mid models: gpt-4o-mini, claude haiku, gemini flash, deepseek, llama, mistral, qwen. Full wire compatibility incl. tools/function-calling and response_format. GET /v1/models lists every model. Streaming supported (stream: true).
Output
An OpenAI-compatible chat completion object containing the assistant's reply message, finish reason, and token usage counts (prompt, completion, total). The response mirrors the standard OpenAI /v1/chat/completions response schema.
Example use cases
Example prompt
“Send this conversation to gpt-4o-mini and get a reply — I want to pay per call in USDC, no API key: messages are [{"role":"user","content":"Summarize the French Revolution in 3 bullet points"}], cap the output at 300 tokens.”
Technical details
Endpoint
POSThttps://agent402.tools/v1/chat/completionsWhen to prefer
Choose this endpoint when you need OpenAI-SDK-compatible chat completions but want to pay per call in USDC via x402 rather than managing API keys or subscriptions. It is ideal for agents operating on crypto-native payment rails (Base, Solana, Polygon, Arbitrum, Stellar), serverless or wallet-authenticated workflows, or when you want budget model access (gpt-4o-mini, Claude Haiku, Gemini Flash) without committing to a monthly plan. Prefer it over the auto-routing sibling endpoint when you want explicit model control.
Side effects
- Payment insufficient or x402 handshake fails — upstream returns 402 with a payment-required header
- Model ID not on the allowed tier allowlist — returns an error listing valid model IDs
- ZDR requested but no zero-data-retention provider available for the chosen model — walks failover chain and may error
- max_tokens exceeds tier maximum — clamped silently or rejected
- Provider upstream timeout or outage — error propagated from OpenRouter
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| zdr | boolean | Optional - true routes only to zero-data-retention providers (OpenRouter provider.zdr); the only provider preference a caller may set. |
| model | string | Model id - OpenRouter form (openai/gpt-4o-mini) or bare OpenAI form (gpt-4o-mini). GET /v1/models lists the allowlist per tier. Optional: omit it and the tier serves its documented default (x402.defaultModel on /v1/models), named back in agent402_default_model; the price does not change |
| tools | array | Optional - OpenAI function tools {type:"function", function:{...}}, or a tool namespace {type:"namespace", name, tools:[...]} (flattened into its functions). The pro and premium routes also accept the bounded server tools openrouter:web_search, openrouter:web_fetch and openrouter:datetime with server-owned limits (GET /v1/models lists them); stop_server_tools_when and max_tool_calls are refused. A request with a server tool is never served from the prompt cache. |
| messages | array | OpenAI chat messages: [{role, content}] - text and image_url content blocks supported |
| reasoning | object | Optional - {effort: "none"|"minimal"|"low"|"medium"|"high"|"xhigh"|"max", max_tokens?, exclude?, enabled?}. Reasoning tokens count against max_tokens. Omitted: low effort on the budget tiers, the model default on premium. reasoning_effort (string) is accepted as an alias. |
| max_tokens | number | Output token cap (clamped to the tier maximum) |
| cache_control | — | Optional - prompt caching preference. Default ON ({type:"ephemeral"}, 5-minute TTL): repeated prefixes across your turns are served from the provider cache (same price to you). Send false to disable. ttl:"1h" is not offered. |
| max_completion_tokens | integer | Optional - alias of max_tokens (newer OpenAI SDKs send this). |
Output
Schema · Response
{
"type": "json",
"example": {
"id": "gen-…",
"model": "openai/gpt-4o-mini",
"usage": {
"total_tokens": 13,
"prompt_tokens": 12,
"completion_tokens": 1
},
"object": "chat.completion",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "OK"
},
"finish_reason": "stop"
}
],
"created": 1750000000
}
}Tags
x402
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