Pi Spend

Answer "what have my metered models cost me lately" from Pi's own session telemetry. Periods are today, the current week (Monday start), the current calendar month, and all recorded history, all in the machine's local timezone.

Usage

/pi-spend                       # all four periods, every provider and model
/pi-spend --metered-only        # show only responses classified as metered
/pi-spend --period today        # single period; repeatable
/pi-spend --json                # normalized schema v2 JSON
/pi-spend --billing-policy PATH # use another effective-dated local policy
/pi-spend --router-config PATH   # explicit legacy current-policy projection

Resolve scripts/pi_spend.py relative to this SKILL.md and run it with the user's arguments:

/path/to/pi-spend/scripts/pi_spend.py --metered-only

Do not substitute ad-hoc transcript greps or provider billing calls for the collector.

Output contract

Paste the collector's complete stdout verbatim in a fenced code block, even when the tool card already shows it. Do not summarize, reformat, or truncate the table. Use a json fence for --json and a plain-text fence otherwise.

Analysis contract

After the verbatim block, add two to four bullets, at most 120 words:

• name the largest metered rows for the requested period and what drove them, distinguishing cache-read volume from fresh input;
• state the metered total separately from the subscription total, and never add them into one "spend" figure;
• call out the unknown billing class when present, since it means no valid interval covers that exact provider/model response rather than that the model is free;
• call out legacy-current-router-policy as a current-policy projection that may relabel history; and
• mention responses that recorded no cost only when the collector reports some.

Never describe the output as an invoice, an account balance, or remaining credits.

Sources and authority

• Pi sessions: ~/.pi/agent/sessions/**/*.jsonl. Assistant messages carry provider, model, usage, and a per-response usage.cost breakdown. Responses are deduplicated by responseId, so nested subagent run transcripts are counted once.
• Billing class: ~/.pi/agent/pi-spend-billing-policy.json, using exact provider/model entries and the interval covering each response timestamp. Missing or invalid coverage reports as unknown; the collector does not guess from provider or model names.

Pi is the only local harness that records cost. Claude Code transcripts contain no cost field and Codex rollouts record cumulative token counts only, which is why this skill is Pi-scoped.

Billing policy

The local policy uses schema version 1. effectiveUntil is exclusive; null leaves the interval open. Timestamps must be timezone-aware UTC (Z or +00:00). Intervals for one exact model may be contiguous but must not overlap.

{
  "schemaVersion": 1,
  "models": {
    "provider/model-id": [
      {
        "effectiveFrom": "2026-01-01T00:00:00Z",
        "effectiveUntil": "2026-07-01T00:00:00Z",
        "billing": "metered"
      },
      {
        "effectiveFrom": "2026-07-01T00:00:00Z",
        "effectiveUntil": null,
        "billing": "subscription"
      }
    ]
  }
}

Add a new interval when billing changes; do not rewrite the earlier interval. Renamed models get a separate exact key. There are no aliases or automatic historical backfills. Back up this unshared file with the retained Pi sessions it classifies.

Missing files, malformed policy JSON, duplicate keys, non-UTC timestamps, invalid ranges, overlaps, and uncovered response dates fail closed to unknown with bounded diagnostics. An invalid model entry does not disable valid, non-overlapping entries for other models.

--router-config PATH preserves the old modelPolicies[*].metered interpretation only when invoked explicitly. Its rows and report metadata are labelled legacy-current-router-policy because current router policy is projected across all history and can relabel older responses. Bare model-name fallback is not supported.

JSON schema

Schema v2 adds top-level billingPolicy source/status/diagnostics, classification counters under stats, and billingSource on each row. A single provider/model may produce multiple rows in one period when its billing interval changes. costAuthority remains pi-catalog-estimate.

Limitations

• Cost is Pi's own catalog list-price calculation at response time, not a provider invoice, subscription allowance, or credit balance. Treat it as an estimate for relative comparison.
• Subscription-billed providers still get a computed cost. That figure is notional and is not charged; keep it out of any metered total.
• Coverage is bounded by retained session files. History starts at the oldest surviving transcript, so all may be shorter than it appears and older periods are not recoverable.
• The unshared billing policy is trusted local configuration, not a tamper-proof history. Explicitly rewriting an old interval can still change reports.
• Metered models may bill through different pools, for example direct Anthropic versus OpenRouter. Reconcile each provider against its own dashboard before treating a figure as owed.
• Responses missing a cost block are excluded from the estimate and reported as a count rather than counted as zero. Undated and future-dated responses are also excluded and counted separately.

See also

• /token-dashboard for cross-harness token telemetry across Claude Code, Pi, Codex, and OpenRouter, scoped to the current session and UTC week. It is deliberately token-only; this skill is the cost view and covers Pi alone.
• /model-update-check for auditing router and panel model IDs against the live catalog.