{"uid":"cap_jXfxRXGBngg6vEPvPRxIX","slug":"chit402-a2a-message-paid-llm-inference-with-usdc-receipts-871ac5ed","name":"Chit402 A2A Message — Paid LLM Inference with USDC Receipts","description":"Who paid which call — export, policy, evidence. Possession book for agent spend.","url":"https://api.chit402.com/a2a-message","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"type":"string","description":"Model id from GET /v1/models; xfuel/auto routes automatically"},"stream":{"type":"boolean"},"messages":{"type":"array","items":{"type":"object","required":["role","content"],"properties":{"role":{"enum":["system","user","assistant"],"type":"string"},"content":{"type":"string"}}},"description":"OpenAI-style chat messages array"},"max_tokens":{"type":"integer","description":"Output token budget"},"temperature":{"type":"number","maximum":2,"minimum":0}}},"responseSchema":{"type":"json","example":{"id":"chatcmpl-abc123","model":"xfuel/auto","usage":{"total_tokens":15,"prompt_tokens":10,"completion_tokens":5},"xfuel":{"verify_url":"https://api.xfuel.app/receipt/xfuel-abc123"},"object":"chat.completion","choices":[{"index":0,"message":{"role":"assistant","content":"Hello!"},"finish_reason":"stop"}],"created":1700000000}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_wxKQWr6Lr9yusZ-naPDC2","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Sends a chat completion request to a paid LLM endpoint over x402, deducting USDC per call and returning an OpenAI-compatible response with a verifiable receipt URL.","exampleAgentPrompt":"Send a chat message to Chit402 using the xfuel/auto model — the message is 'Summarize the concept of zero-knowledge proofs in two sentences', cap it at 200 tokens, and give me back the response along with the receipt URL so I can verify the payment.","exampleUseCases":[{"title":"Agent fleet spend tracking","prompt":"Send this system prompt and user query to Chit402 using xfuel/auto, keep it under 300 tokens, and save the receipt URL it returns — I need a verifiable record of every AI call my agent fleet makes for our monthly audit."},{"title":"Cost-plus LLM call with budget cap","prompt":"Call Chit402 with the message 'Draft a two-sentence product description for a wireless ergonomic keyboard', use xfuel/auto, set max_tokens to 150, and tell me how many tokens it used and what the receipt URL is so I can track the spend."},{"title":"Streamed inference with payment receipt","prompt":"Send a streamed chat request to Chit402 — model xfuel/auto, temperature 0.7, max 500 tokens — asking 'Write a short poem about blockchain', and once it's done give me the verify URL from the response so I can confirm the USDC was charged correctly."}],"resultDescription":"Returns an OpenAI-compatible chat completion JSON object containing the assistant's reply in `choices[0].message.content`, token usage breakdown (`prompt_tokens`, `completion_tokens`, `total_tokens`), the model used, a unique completion ID, and an `xfuel.verify_url` field linking to a verifiable payment receipt for the call.","failureModes":["Insufficient USDC balance — x402 payment fails before inference begins","Invalid model ID — returns error if model string not found in /v1/models","Malformed messages array — missing required `role` or `content` fields causes validation error","Token budget exceeded — response truncated if max_tokens is too low","Temperature out of range — values outside 0–2 rejected","Network or payment gateway timeout — call fails with no receipt generated"],"whenToPreferThis":"Choose this endpoint when your agent needs verifiable, auditable records of every LLM call with a linked payment receipt — ideal for multi-agent systems where spend accountability, policy compliance, or cost-plus billing evidence is required. Prefer it over generic LLM APIs when you need USDC micropayment settlement on Base or Solana, OpenAI-compatible message format, and a per-call receipt URL for treasury or audit purposes.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:30:04.067Z","isFirstParty":false}