{"uid":"cap_h9ciMO6DaMiLp_XRstTlv","slug":"model-access-gateway-gpt-oss-120b-chat-completions-x402-0302c981","name":"Model Access Gateway – GPT-OSS-120B Chat Completions (x402)","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://agent402-arb.rosariovitale0096.workers.dev/llm/gpt-oss-120b?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"model":{"type":"string","description":"Optional: fixed by the route (openai/gpt-oss-120b)"},"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-oss-120b","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":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_lndjemfbC0LRiMshlAw3F","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","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 using the GPT-OSS-120B model, billed per-request in USDC via x402 with no API key required.","exampleAgentPrompt":"Send this conversation to GPT-OSS-120B and get a reply — the system prompt is 'You are a helpful assistant' and the user message is 'Explain quantum entanglement in two sentences.' Pay the per-call fee automatically in USDC.","exampleUseCases":[{"title":"Permissionless LLM for autonomous agent","prompt":"I need you to call a 120B-parameter chat model to draft a reply to this customer email — use the system prompt 'You are a professional customer support agent' and the user message is the email text below. Pay automatically per call in USDC, no API key needed."},{"title":"Crypto-native AI text generation pipeline","prompt":"Run a chat completion using GPT-OSS-120B: system prompt is 'You are a creative copywriter', user message is 'Write a 3-sentence product description for a noise-cancelling headphone.' Bill it in USDC via x402."},{"title":"Multi-step reasoning in an agent workflow","prompt":"I'm building an agent that needs to reason through a logic puzzle — send this chain-of-thought prompt to GPT-OSS-120B: system 'Think step by step', user 'If all bloops are razzles and all razzles are lazzles, are all bloops lazzles?' and return the full completion."}],"resultDescription":"Returns a standard OpenAI chat.completion JSON object containing the assistant's message content, role, finish_reason (e.g. 'stop'), model name, creation timestamp, and token usage breakdown (prompt_tokens, completion_tokens, total_tokens).","failureModes":["Payment not included or insufficient USDC — HTTP 402 returned before inference runs","Malformed request body missing required 'messages' field — returns 400 or model error","Model overloaded or upstream provider unavailable — may return 503 or timeout","Invalid x402 payment header or wrong network — payment rejected, no completion returned","Rate limit hit on underlying model provider — upstream 429 propagated"],"whenToPreferThis":"Choose this endpoint when you need OpenAI-compatible chat completions without registering for an API key or pre-purchasing credits — ideal for autonomous agents that can pay per-call in USDC on Base via x402. Prefer it over standard OpenAI when you want crypto-native, account-free billing or when operating in a permissionless agent economy. It is specifically suited to the GPT-OSS-120B model; choose a sibling endpoint for other models in the gateway.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-17T21:28:10.711Z","isFirstParty":false,"canonicalSlug":"model-access-gateway-gpt-oss-120b-chat-completions-x402-0302c981"}