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cost-burn

cost-burn

github.com/ruvnetData & databases80.0k248 installsUpdated today
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About cost-burn

cost-burn tracks changes in production spending rates for teams monitoring usage costs. It compares the latest time bucket with the mean of prior non-empty buckets and can alert when acceleration exceeds a threshold.

Key features

  1. 01Aggregate session spend by time bucket
  2. 02Compare latest spend with prior mean
  3. 03Alert on configurable acceleration thresholds
  4. 04Gate CI runs on cost changes
  5. 05Skip alerts without a history baseline

Use cases

  1. 01Spot sudden increases in production spend
  2. 02Catch cost acceleration before budget alerts
  3. 03Block threshold breaches in CI

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/ruvnet/ruflo --skill cost-burn

After installing, type/cost-burnin Claude Code to confirm it loaded.

Details

From the project README

Burn-rate trend observability. The fourth leg of the cost-tracker forward-cost stack:

QuestionSkill
"Have we crossed a threshold?" (reactive)cost-budget-check
"When will we cross a threshold?" (predictive)cost-projection
"Could we have spent less?" (comparative)cost-counterfactual
"Is daily burn ACCELERATING?" (trend)cost-burn ← this

Algorithm

Implementation: scripts/burn.mjs.

  1. Read all session-* records from cost-tracking namespace.
  2. Bin into --bucket duration windows (default 1d) over --lookback (default 14d).
  3. For each bucket: {n: sessions, spendUsd: sum(total_cost_usd)}.
  4. Compute delta = latest.spendUsd - mean(prior non-empty buckets).
  5. If --alert-on-acceleration-pct N is set: exit 1 when deltaPct > N.

Smoke transcript (5 days @ $0.10/day, today $0.50 — 400% acceleration)

| Latest bucket spend | $0.500000 (1 sessions) |
| Prior bucket mean | $0.100000 (4 non-empty buckets) |
| **Delta (latest vs prior mean)** | **+$0.400000 (400.00%)** |

# | Window                              | Sessions | Spend
0 | 2026-06-15 14:16 → 2026-06-16 14:16 | 1        | $0.500000
1 | 2026-06-14 14:16 → 2026-06-15 14:16 | 0        | $0.000000
2 | 2026-06-13 14:16 → 2026-06-14 14:16 | 1        | $0.100000
3 | 2026-06-12 14:16 → 2026-06-13 14:16 | 1        | $0.100000
...

Drift alert exit code

$ cost burn --bucket 1d --lookback 7d --alert-on-acceleration-pct 50 ⚠ ALERT: latest bucket $0.500000 is 400.0% above prior mean $0.100000 (threshold +50%) exit 1

$ cost burn --bucket 1d --lookback 7d --alert-on-acceleration-pct 500 ✓ latest bucket within +500% of prior mean (actual delta: 400.0%) — OK exit 0

CI integration

# Fail the build if today's spend accelerated > 100% over the weekly mean
cost burn --bucket 1d --lookback 7d --alert-on-acceleration-pct 100 || alert-oncall

The alert is independent of budget — it triggers on rate ACCELERATION even when total spend is well under budget. Catches "we shipped a hot loop that burns 10× normal" before the budget alarm goes off.

Distinct from cost-trend

SkillData sourceQuestion
cost-trenddocs/benchmarks/runs/*.json"Is the benchmark drifting (win rate, latency)?"
cost-burncost-tracking namespace"Is production spend accelerating?"

Both useful; they answer different questions on different data.

Edge cases

  • Sparse history (no prior non-empty buckets): alert is SKIPPED with a reason string, exit 0. Operators don't get spurious alerts on cold-start.
  • Prior buckets all $0 but latest > $0: delta is Infinity/null in JSON, marked new in the table. No alert fires (no baseline to compare against).
  • --bucket > --lookback: hard error, exit 2.

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