{"uid":"cap_LgD7Au5-azSnnEiZSkQiU","slug":"model-access-gateway-gpt-6-astra-chat-completions-x402-usdc-eec3c903","name":"Model Access Gateway – GPT-6 Astra Chat Completions (x402, USDC)","description":"LLM inference API: OpenAI-compatible chat completions for 136 AI models (Claude, GPT, Gemini, Grok, DeepSeek, Qwen, Kimi, GLM), paid per call in USDC on Base with x402. No account, no API key, automatic refund if the model fails.","url":"https://modelaccessgateway.com/llm/gpt-6-astra?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"type":"string","description":"Optional: fixed by the route (openai/gpt-6-astra)"},"tools":{"type":"array"},"stream":{"type":"boolean","description":"true: server-sent events after payment"},"messages":{"type":"array","items":{"type":"object","required":["role"],"properties":{"role":{"enum":["system","user","assistant","tool","developer"],"type":"string"},"content":{"type":["string","array","null"]}}},"minItems":1},"max_tokens":{"type":"integer","maximum":16384,"minimum":1,"description":"Optional, default 4096"},"temperature":{"type":"number","maximum":2,"minimum":0},"response_format":{"type":"object"}}},"responseSchema":{"type":"json","example":{"id":"chatcmpl-7f3c2a91","model":"openai/gpt-6-astra","usage":{"total_tokens":10,"prompt_tokens":9,"completion_tokens":1},"object":"chat.completion","choices":[{"index":0,"message":{"role":"assistant","content":"OK"},"finish_reason":"stop"}],"created":1791979200}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.0019","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":"$0.0019/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0019","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0019","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_jgeXQplGDf87laDStmqnm","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.0019","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Runs OpenAI-compatible chat completions against GPT-6 Astra, billed per-call in USDC via x402 with no account or API key required.","exampleAgentPrompt":"Ask GPT-6 Astra to write a concise executive summary of the following text, paying per-call in USDC — no API key needed: 'Our Q3 revenue grew 18% YoY driven by enterprise upsells and reduced churn.'","exampleUseCases":[{"title":"Autonomous agent LLM calls without API keys","prompt":"I'm building an autonomous agent that needs to call GPT-6 Astra at runtime without hardcoding any API keys — just have it pay per call in USDC. Send the message 'What is the capital of France?' with a max of 256 tokens and temperature 0.2."},{"title":"On-demand document summarisation","prompt":"Summarise this legal clause into plain English using GPT-6 Astra, streaming the response back as it's generated: 'The licensor hereby grants a non-exclusive, non-transferable, revocable license...' — use up to 512 tokens."},{"title":"Tool-augmented reasoning with crypto payment","prompt":"Call GPT-6 Astra with a system prompt saying 'You are a helpful coding assistant' and a user message asking it to write a Python function that reverses a linked list — use max 1024 tokens and temperature 0.7, and just pay the USDC fee automatically."}],"resultDescription":"Returns an OpenAI-compatible chat.completion JSON object containing the assistant's message content, finish reason, token usage (prompt, completion, total), model identifier, and a unique completion ID. Streaming mode returns server-sent events with incremental content deltas.","failureModes":["Model provider error triggers automatic USDC refund","Insufficient USDC balance results in 402 payment required error","Invalid messages array (missing role or empty array) causes 400 validation error","max_tokens exceeds 16384 limit returns schema validation error","Unsupported role value in messages causes rejection","Network timeout during streaming may result in partial response"],"whenToPreferThis":"Choose this endpoint when you need GPT-6 Astra specifically and want truly frictionless, account-free access — no API key provisioning, no subscription, just pay $0.0023 USDC per call on Base. Ideal for autonomous AI agents that manage their own crypto wallets, one-off tasks where setting up an OpenAI account is overkill, or multi-agent systems that need to spin up LLM calls dynamically with automatic refunds on model failure.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-18T06:47:37.364Z","isFirstParty":false,"canonicalSlug":"model-access-gateway-gpt-6-astra-chat-completions-x402-usdc-eec3c903"}