Cost Report

Print the spend summary the stop:cost-tracker hook accumulates in
~/.local/share/kbg/metrics/costs.jsonl: every session on this machine, all projects, subagent
spend split out by agent type. Native /usage (/cost) covers only the live session.

Run

One Bash call. The script reads, dedups and prints; do not open the log or add rows by hand.

node "${CLAUDE_SKILL_DIR}/scripts/cost-report-dedup.js"

/cost-report csv prints the last 100 raw rows instead. MH_COSTS_FILE=<path> points at another
log; use it only when the user or task names one.

A missing log prints Cost tracker not set up and exits 0. Relay that line and say the log fills
after the first session ends with the hook enabled. Never invent numbers. If node is missing,
say so; there is no other runtime.

Read back

Quote the script's numbers as printed. Add only what a reader needs:

• Whole machine, not this project. The report never groups by project; compare trends over days.
• warning: lines mean unknown, not zero. Those sessions had only jq_failed rows and are
  left out of every total; say their spend is unknown.
• note: lines first. Rows before 2026-09-04 summed tokens per transcript line and run about
  2.4x high; a short run after that reads about 39% low on output. A total mixing eras is a
  ceiling, not a bill. Say which note applies before quoting total.
• (rate unverified) means guessed (priced at the Sonnet rate). Rank those by tok, not dollars.
• Non-Claude models are history (proxy models only appear before 2026-08-07).
• Subagent spend starts 2026-08-07. A difference across that date is a schema change.
• Codex invocations are counts, never dollars; the section is absent until codex:* ran.
• ledger cross-check: compares, it does not replace. Quote total. The gap is spend with no
  transcript line. no ledger data means mh's hooks module was not running, not zero spend;
  module loaded: N of M sessions is its load rate.
• Handoff cost (2026-09-20+ rows): median/p90 tokens main spends reading each subagent return,
  plus returns per orchestrator turn. Omitted when no row carries it.

Never re-estimate prices from raw tokens; the rate table lives in hooks/stop/cost-tracker.sh.

Data model and dedup rule

Schema and legacy eras: references/data-model.md. The rule that must not regress: per session,
keep the latest row per (session_id, stream, model, agent_type) and sum across keys; a row
with no stream counts as orchestrator. Run tests/skills/test-cost-report.sh after any change
to the script.