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 useful, but they rarely solve AI cost tracking per feature unless you enrich them with business context and retry metadata. The practical operating model is simple: calculate cost on every request, attach ownership dimensions, then roll the data up into team, feature, and customer views. If you are searching for "LLM cost attribution per request," you are usually already past the basic billing problem. You can see your OpenAI or Anthropic invoice, but you cannot answer the questions finance and engineering actually care about: which feature drove the spike, which team owns it, which customers are unprofitable, and which prompt or model change caused the jump. That is why per-request attribution matters. It turns AI spend from a monthly surprise into an operational metric you can act on in the same day. Why LLM cost attribution per request matters now According to the FinOps Foundation's 2025 State of FinOps report, 63% of respondents now manage AI spending, up from 31% the year before. That jump is the real signal. AI cost is no longer a side bucket inside cloud spend. It is becoming a first-class FinOps workload. For teams spending $5,000 to $50,000 per month on LLM APIs, averages break down quickly. A support assistant, an internal coding copilot, and a customer-facing generation feature can all hit the same vendor account while having completely different margins, latency targets, and prompt shapes. If you only look at total spend by provider, you lose the unit economics. Per-r