> ## Documentation Index
> Fetch the complete documentation index at: https://docs.useharmonia.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Pricing and budget reference

> Versioned model pricing, reservations, observed usage, and paid-operation policy.

`agent/harmonia_agent/model_catalog.py` is the versioned pricing catalog. Unknown model prices fail closed. Each eligible invocation reserves an estimated amount before dispatch and resolves the reservation afterward as observed, not invoked, or uncertain.

`UsageRecord` in `src/lib/types.ts` records job, operation, stage, role, model, units, estimated and observed cost, pricing version, policy snapshot, trace ID, and timestamp. Job budgets track estimated, observed, reserved, limit, and approval-threshold USD values.

| Principle                     | Rule                                                                  |
| ----------------------------- | --------------------------------------------------------------------- |
| Estimate before dispatch      | No paid invocation without a known catalog entry and available budget |
| Reconcile after dispatch      | Record observed cost when available; retain uncertainty honestly      |
| Preserve lineage              | Usage shares operation and trace identifiers with the invocation      |
| Separate money from authority | Available budget does not approve publishing or other effects         |

See [Usage and budget tracking](/platform/observability/usage-budget) for the implementation map.