{"uid":"cap_J9OsG0-Ci5Qqbkiy2b2vY","slug":"gpt-5-5-metered-chat-completions-get-x402-guarantee-deposit-c1f6ff6e","name":"GPT-5.5 Metered Chat Completions (GET, x402 Guarantee Deposit)","description":"GPT-5.6 Luna API Base USDC and OpenAI-compatible x402 chat: one request for $0.00293, paid by browser wallet or a quote-first agent fallback.","url":"https://gpt55.558686.xyz/v1/chat/completions/metered","method":"GET","headers":{},"bodySchema":{"type":"object","$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-luna","gpt-5.6-terra","gpt-5.5","gpt-5.3-codex","gpt-5.4"],"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-5.5."},"finish_reason":"stop"}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.523889","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":"$0.523889/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.523889","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.523889","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_xynIQv8s6Us66EnrYrxZh","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.523889","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"GET-based OpenAI-compatible GPT-5.5 chat completions endpoint with usage-metered x402 pricing and a pre-payment guarantee deposit quote of $0.523889 USDC; unused deposit is credited back after actual usage is settled.","exampleAgentPrompt":"Ask GPT-5.5 the following using metered x402 pricing — system prompt: 'You are a helpful assistant', message: 'Explain quantum entanglement in simple terms', max 500 tokens, and give me the $0.523889 guarantee deposit quote before we proceed.","exampleUseCases":null,"resultDescription":"Returns an OpenAI-compatible chat completion object with an id, object type, model name, choices array containing the assistant's message, and a usage object detailing prompt/completion token counts. The $0.523889 USDC guarantee deposit is charged upfront; any unused portion is credited back to the caller's internal balance once upstream token usage is confirmed.","failureModes":["Payment not provided or x402 payment header missing — returns 402 Payment Required","Model parameter not set to 'gpt-5.5' — may return 400 Bad Request or route mismatch","max_tokens exceeds 128000 — schema validation error","No prompt/input/message query parameter provided — returns 400 missing required input","Upstream OpenAI API unavailable — 502 or 503 proxy error","Deposit insufficient for actual usage — may result in balance adjustment or partial response"],"whenToPreferThis":"Choose this endpoint when you need GPT-5.5 chat completions via a GET request (useful for browser, curl, or agent environments that cannot easily POST JSON bodies), want usage-metered x402 micropayment billing with a transparent pre-payment deposit, and prefer discounted token rates (input $5/1M, cached $0.5/1M, output $30/1M multiplied by 0.111112) with automatic credit-back of unused deposit. Prefer over POST variants when query-parameter-based invocation is required.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T12:30:44.149Z","isFirstParty":false}