LLM Cost Attribution Per Request: How to Track OpenAI and Anthropic Spend by Team and Feature

Per-request attribution starts with five fields on every call: provider, model, input tokens, output tokens, and ownership tags such as team, feature, and customer. A monthly vendor bill cannot explain why one feature, one tenant, or one prompt template suddenly became expensive. Request-level math can. As of June 8, 2026, OpenAI lists GPT-5.4 mini at $0.75 per 1M input tokens and $4.50 per 1M output tokens, while Anthropic lists Claude Sonnet 4 at $3 and $15 respectively. Gateway logs are usefu...