{"uid":"cap_cfhbaCjGPw4iaeY4P3FXE","slug":"gpt-5-6-luna-chat-completions-x402-get-fd1b37fe","name":"GPT-5.6 Luna Chat Completions (x402, GET)","description":"GPT-5.6 Luna API Base USDC and OpenAI-compatible x402 chat: one request for $0.00293, paid by browser wallet or a quote-first agent fallback.","url":"https://gpt55.558686.xyz/v1/chat/completions/gpt-5.6?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"pathParams":{"type":"object","additionalProperties":true},"queryParams":{"type":"object","properties":{"q":{"type":"string"},"input":{"type":"string"},"model":{"enum":["gpt-5.6-sol","gpt-5.6","gpt-5.6-terra","gpt-5.5"],"type":"string"},"prompt":{"type":"string"},"system":{"type":"string"},"message":{"type":"string"},"max_tokens":{"type":"integer","maximum":128000,"minimum":1},"system_prompt":{"type":"string"},"max_output_tokens":{"type":"integer","maximum":128000,"minimum":1}},"additionalProperties":true}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","required":["id","object","model","choices"],"properties":{"id":{"type":"string"},"model":{"type":"string"},"usage":{"type":"object"},"object":{"type":"string"},"choices":{"type":"array"}},"additionalProperties":true}}}}},"responseSchema":{"type":"json","example":{"id":"chatcmpl_example","model":"gpt-5.6-luna","usage":{"total_tokens":44,"prompt_tokens":32,"completion_tokens":12},"object":"chat.completion","choices":[{"index":0,"message":{"role":"assistant","content":"A concise answer from GPT-5.6 Luna."},"finish_reason":"stop"}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.099995","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":"$0.099995/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.099995","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.099995","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_4NrJuWipZfEqC-jBConYa","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.099995","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Generates OpenAI-compatible chat completions via a GET request using the GPT-5.6 Luna model, paid per-call in USDC over x402.","exampleAgentPrompt":"Using the GPT-5.6 Luna model, answer this question in under 200 tokens: 'What are three practical benefits of using micropayment APIs for AI agents?'","exampleUseCases":[{"title":"One-shot Q&A for an agent pipeline","prompt":"Ask the GPT-5.6 Luna model: 'Summarize the key difference between REST and GraphQL in two sentences' — keep the response under 150 tokens."},{"title":"Routing decision in a multi-agent workflow","prompt":"I need a quick routing decision: given the user message 'I want to cancel my order', classify the intent as one of: refund, cancel, or complaint. Use GPT-5.6 Luna and return just the label."},{"title":"Extraction helper for structured data","prompt":"Extract the company name, role, and start date from this text using GPT-5.6 Luna: 'Jane joined Acme Corp as a Senior Engineer in March 2022.' Return the result as JSON."}],"resultDescription":"Returns an OpenAI-compatible JSON chat completion object containing the assistant's generated message, model ID, finish reason (e.g. 'stop'), and token usage breakdown (prompt, completion, total tokens).","failureModes":["Payment not authorized or insufficient USDC balance — x402 payment required error","Invalid or unsupported model enum value — request rejected","prompt or message parameter missing — required field validation error","max_tokens exceeds 128000 limit — schema validation failure","Upstream model unavailable or rate-limited — 5xx error from provider","Malformed GET query parameters — parsing error"],"whenToPreferThis":"Choose this endpoint when you need a lightweight, pay-per-call OpenAI-compatible chat completion without a subscription, especially in agent pipelines that support x402 micropayments in USDC. It is well-suited for short, one-shot prompts, routing decisions, or extraction tasks where the Luna model variant's cost profile ($0.00293 per call) is acceptable and a GET-based interface is preferred over POST.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-21T12:30:19.462Z","isFirstParty":false,"canonicalSlug":"gpt-5-6-luna-chat-completions-x402-get-fd1b37fe"}