x402engine GPT-5.2 LLM API

Choose this endpoint when you need OpenAI's most capable GPT-5.2 model with no subscription or API key setup, paying only per call via USDC micropayments. Ideal for AI agents that need occasional high-quality reasoning, coding, or multimodal analysis without committing to a monthly plan. Prefer this over GPT-4 or Claude endpoints when GPT-5.2's top-tier reasoning or specific OpenAI model behavior is required.

• Payment not included or insufficient USDC — returns HTTP 402 with payment required details
• Invalid or malformed message format — returns 400 with schema validation error
• Rate limit or capacity exceeded — returns 429 or 503
• Prompt triggers content policy — returns refusal or 400
• Network timeout on long-form generation — returns 504 or incomplete response