Agent402.tools Metered Anthropic Messages API

x402

Agent402.tools Metered Anthropic Messages API is a paid API for AI agents from agent402.tools, paid per call via x402, $0.187875/call, status unknown (last checked 2026-11-03, last successful call 2026-10-02).

Forwards requests to the Anthropic Messages API with per-call billing via x402 micropayments, priced at 1.15× model list price (input+output tokens) with a $2 cap

Price / call$0.187875

Seller volume →—

Success99%

StatusUnknown

How this service works

The Anthropic Messages wire priced from the request itself: the 402 quotes this exact body, from $0.001, with upto buyers settling actual usage under the quote. Use it when an agent built on the Anthropic SDK, or Claude Code, needs any supported model paid per call with no account.

Output

Returns an Anthropic Messages API response object containing the assistant's content blocks (text, tool_use, etc.), the model used, token usage counts (input and output), a stop_reason, and a unique message ID — identical to the native Anthropic API response format.

Example use cases

Agentic LLM calls without subscription

“I want my agent to call Claude Sonnet for each user query without committing to a monthly API plan — just charge USDC per request based on actual tokens used, capped at $2 per call.”

Tool-augmented reasoning on demand

“Run a Claude claude-3-5-sonnet call with my custom search tool definition and a system prompt saying 'You are a research assistant' — the message is 'Summarize recent AI safety developments', max 512 tokens, pay per call.”

Streaming Claude inference with micropayment

“Stream a response from Claude on the metered endpoint for the message 'Draft a 3-paragraph product description for a reusable water bottle', using streaming SSE, max 400 tokens, and settle the cost in USDC automatically.”

Technical details

Endpoint

POSThttps://agent402.tools/v1/metered/messages?utm_source=zero.xyz

When to prefer

Choose this endpoint when you need pay-as-you-go access to Claude models with no monthly subscription, when your agent must settle inference costs in USDC via x402 micropayments, or when you want exact token-cost transparency (BPE-counted, 1.15× list price) with a per-call cap. Prefer it over direct Anthropic API when operating in agentic finance pipelines where on-chain payment settlement is required, or when you want to avoid credit card billing and instead pay per inference call programmatically.

Side effects

402 Payment Required if x402 payment header is missing or insufficient
400 Bad Request if model ID is not on the allowlist for the selected tier
400 if max_tokens exceeds the tier output cap
Model unavailable if requested model is temporarily offline
Payment settlement failure if USDC balance or card authorization is insufficient
Timeout or streaming interruption on very long generation requests

Input

Schema · Request body

Field	Type	Description
zdr	boolean
model	string
tools	array
effort	string
stream	boolean
system	string
messages	array
thinking	object
max_tokens	integer

Output

Schema · Response

{
  "type": "json",
  "example": {
    "note": "full example in /openapi.json",
    "truncated": true
  }
}

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