{"uid":"cap_FXdZ9lp1PIgTkS42DwRWb","slug":"hearth-ai-chat-x402-pay-per-call-732c204e","name":"Hearth AI Chat (x402 Pay-Per-Call)","description":"One-shot LLM completion for agents: send a prompt (and optional system message), get the answer text. Flat $0.002 per call, no account or API key; cheaper than typical x402 chat proxies. Up to ~2,000 chars of prompt and 600 output tokens. GET or POST JSON {prompt, system}.","url":"https://138-197-15-135.sslip.io/v1/ai/chat?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["queryParams"],"properties":{"queryParams":{"type":"object","required":["prompt"],"properties":{"prompt":{"type":"string","description":"User prompt (max 2000 chars)"},"system":{"type":"string","description":"Optional system message (max 1000 chars)"},"max_tokens":{"type":"string","description":"Max output tokens, 16-600 (default 400)"}}}}},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string","const":"json"},"example":{"type":"object","required":[],"properties":{"text":{"type":["string","null"]},"model":{"type":["string","null"]},"usage":{"type":["object","null"]}}}}}}},"responseSchema":{"type":"json","example":{"text":"bullish","model":"gpt-5-nano","usage":{"promptTokens":30,"completionTokens":2}}},"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_4I_MDfW64rmTYXq7UAWyX","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":"Runs a single-turn LLM prompt-completion via a pay-per-call API, billed at $0.002 USDC per request using the x402 micropayment protocol on Base.","exampleAgentPrompt":"Ask the AI chat endpoint to summarize the following in 2 sentences using up to 300 tokens: 'Blockchain technology enables decentralized, trustless record-keeping across distributed networks, removing the need for central intermediaries.'","exampleUseCases":[{"title":"Quick sentiment label for trading signal","prompt":"Send this text to the AI and tell me if it's bullish or bearish, keep the answer short — use at most 50 tokens: 'ETH gas fees dropped 40% after the latest upgrade and DeFi volumes are surging.'"},{"title":"One-shot content draft for a social post","prompt":"Generate a punchy two-sentence tweet about the launch of AI agents paying for APIs with USDC — keep it under 200 tokens and make it sound exciting."},{"title":"Inline Q&A for an agent pipeline step","prompt":"Ask the LLM what the capital of France is and what its population is, limit the response to 80 tokens so it stays concise."}],"resultDescription":"Returns a JSON object containing the generated text string, the model identifier (e.g. 'gpt-5-nano'), and a usage object with promptTokens and completionTokens counts. The text field may be null on failure.","failureModes":["Payment not received or x402 handshake fails — returns 402 Payment Required","Prompt exceeds 2000 character limit — request rejected with validation error","max_tokens out of range (below 16 or above 600) — server returns error","Model unavailable or upstream OpenAI outage — text field returns null","Rate limiting if too many calls in short succession"],"whenToPreferThis":"Choose this endpoint when you need a low-cost, pay-per-call LLM inference with no subscription or API key required, settled instantly in USDC on Base via x402. It's ideal for agents that need occasional or bursty LLM completions, want to avoid monthly billing, or are already operating in the x402 micropayment ecosystem. Not suitable for long-form generation (>600 tokens), streaming responses, or multi-turn conversation state.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-31T18:40:34.160Z","isFirstParty":false,"canonicalSlug":"hearth-ai-chat-x402-pay-per-call-732c204e"}