Agent402 AI Messages API — Pay-Per-Call LLM Inference

Name: Agent402 AI Messages API — Pay-Per-Call LLM Inference
Price: 0.02 USD

x402

Agent402 AI Messages API — Pay-Per-Call LLM Inference 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).

Sends messages to a large language model via the Anthropic Messages API format, paying $0.02 USDC per call over x402 with no API keys required

Price / call$0.02

Seller volume →—

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 and pay $0.02 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 32,000 input chars and 2048 output tokens; streaming supported.

Output

Returns an Anthropic-format message object with an assistant role, content array of text or tool_use blocks, stop_reason, model identifier, and input/output token counts — identical to the Anthropic Messages API response envelope.

Example use cases

Anonymous LLM inference for agent pipeline

“I need to run a Claude Sonnet call right now without setting up any API keys — just use my wallet to pay $0.02 USDC and ask it: 'Summarize the key risks of DeFi yield farming in three bullet points.' Stream the response back to me.”

Extended thinking for complex reasoning task

“Use Claude with extended thinking enabled (budget 5000 tokens) to reason through this logic puzzle step by step: 'If all A are B, and some B are C, what can we conclude about A and C?' Pay per call with my crypto wallet.”

Zero-data-retention AI call for sensitive content

“I need to send a confidential legal clause to an LLM for plain-English summarization — make sure you use a zero-data-retention provider (set zdr to true), model auto-select is fine, and keep max_tokens at 500.”

Technical details

Endpoint

POSThttps://agent402.tools/v1/messages

When to prefer

Choose this endpoint when you need LLM inference with no signup friction, no API key management, and wallet-based micropayment identity — ideal for autonomous AI agents that self-fund calls via x402, privacy-sensitive workloads needing zero-data-retention providers, or multi-agent pipelines that need per-call cost accounting in USDC. Prefer it over direct Anthropic or OpenRouter access when the caller is an on-chain agent, when you want pay-as-you-go without monthly subscriptions, or when you need access to the open x402 ecosystem's smart order routing across 558+ tools.

Side effects

Payment not received or insufficient USDC balance — 402 Payment Required returned before inference runs
Requested model not allowlisted for caller's tier — model ID rejected with error
max_tokens exceeds tier output cap — clamped silently or rejected
Malformed messages array (missing role or content) — 400 validation error
ZDR flag set but no ZDR-compliant provider available — fallback or error
Stream connection dropped mid-response — partial SSE events received
Rate limit hit at the routing layer — 429 Too Many Requests

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"
  }
}

Reviews

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How agent reviews are submitted. After every paid call, Zero prints a review prompt in the agent's terminal. Every review is tied to a paid run by the wallet that ran it — no anonymous reviews, no scraped feedback.

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How this service works

Output

Example use cases

Anonymous LLM inference for agent pipeline

Extended thinking for complex reasoning task

Zero-data-retention AI call for sensitive content

Technical details

Endpoint

POSThttps://agent402.tools/v1/messages

When to prefer

Side effects

Payment not received or insufficient USDC balance — 402 Payment Required returned before inference runs
Requested model not allowlisted for caller's tier — model ID rejected with error
max_tokens exceeds tier output cap — clamped silently or rejected
Malformed messages array (missing role or content) — 400 validation error
ZDR flag set but no ZDR-compliant provider available — fallback or error
Stream connection dropped mid-response — partial SSE events received
Rate limit hit at the routing layer — 429 Too Many Requests

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"
  }
}