llm_cost_tracker is a Rails engine that records what your app spends on LLM APIs - per call, per model, per tag - into your own database, with a mounted dashboard.

0.14.0 adds per-tag budgets: one limit applied to every distinct value of a tag, for as many tags as you declare.

config.budgets.per_tag = {
  tenant_id: { monthly: 1000 },
  user_id:   { daily: 25, behavior: :block_requests }
}

https://github.com/sergey-homenko/llm_cost_tracker