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Xerg reports economics in USD. Every audit summarizes current spend, confirmed waste, opportunity impact, and optional before and after deltas.

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Core audit metrics

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Total spend

The sum of all normalized call costs in the audit window.

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Observed spend

Spend taken directly from the telemetry source when a call already includes cost data.

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Estimated spend

Spend computed from token counts and Xerg’s pricing catalog when observed cost is missing.

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Waste spend

The dollar impact of findings classified as confirmed waste. Today that means:
  • retry waste
  • loop waste
  • cache carryover for Cursor CSV audits when the billed pattern clears the waste bar

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Opportunity spend

The dollar impact of findings classified as opportunity. Today that means:
  • context outliers
  • idle spend
  • downgrade candidates
  • max mode concentration for Cursor CSV audits when the billed mix is heavily premium

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Structural waste rate

This is the conservative waste percentage used by --fail-above-waste-rate.

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Waste by signal source

Local audit summaries include wasteBySignalSource:
  • observedUsd
  • inferredUsd
  • declaredUsd
  • unknownUsd
  • inferredShare
unknownUsd is used for older summaries that predate provenance fields. Xerg does not default missing provenance to observed.

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Breakdowns

Every audit includes spend breakdowns:
  • by workflow
  • by model
Each row includes:
  • spendUsd
  • callCount
  • observedShare
observedShare tells you what fraction of that row’s spend came from directly observed cost rather than estimation.

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Daily rollups

Every audit now includes:
  • spendByDay
  • wasteByDay
These series use UTC calendar days in YYYY-MM-DD format.
  • spendByDay includes spendUsd, observedSpendUsd, estimatedSpendUsd, and callCount
  • wasteByDay includes confirmed waste only
  • sum(spendByDay.spendUsd) reconciles to totalSpendUsd
  • sum(wasteByDay.wasteUsd) reconciles to wasteSpendUsd

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Compare metrics

When a compatible baseline exists and you run xerg audit --compare, Xerg adds:
  • waste rate before and after
  • waste per run before and after
  • waste per 1k calls before and after
  • inferred waste share before and after when provenance is available
  • workload-dependent total spend delta
  • workload-dependent structural waste delta
  • delta run count
  • delta call count
  • top workflow swings
  • top model swings
  • high-confidence waste changes
The compare block leads with normalized rates and per-unit metrics so the before and after read survives workload changes. Absolute spend and waste deltas are still shown, but they are labeled workload-dependent because volume changes can affect them. The push wire schema includes only the top-line comparison fields. The richer workflow, model, and finding-change details stay in the local summary.

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Cost per outcome

When runs carry outcome signals, audits include an outcomes rollup: success rate, cost per successful run, and spend on failed runs. Outcomes come from two places:
  • observed terminal states: explicit success statuses, error or abort stop reasons
  • declared outcomes: xerg outcome --run <id>|--workflow <name> --status success|failure|partial|unknown, stored locally and applied to future audits (declared outcomes override derived ones)
Runs with no outcome signal stay untracked rather than being guessed as successes. Token economics (cache read/write and reasoning tokens, cache spend) are rolled up alongside when the source reports them.

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Notes that always matter

  • Cost per outcome requires outcome signals; audits without any outcome signal say so instead of showing numbers.
  • Opportunity metrics are directional. They are worth testing, but they are not proven waste.
  • Threshold gates only use confirmed structural waste, not opportunity impact.
  • Detected source files with zero included calls are called out explicitly in a count-only extraction note instead of silently vanishing from the audit. Totals may understate real spend when that happens; use xerg doctor --runtime <runtime> --verbose locally to see which files (paths stay on your machine).