cost-track

# Cost Track Reads the active Claude Code session jsonl (`~/.claude/projects/<encoded-cwd>/<session>.jsonl`), tallies assistant-message `usage` per model, computes USD cost using REFERENCE.md pricing, and writes a structured record to the `cost-tracking` AgentDB namespace. This is the **producer** that gives `cost-report` and `cost-optimize` real data to consume. ## When to use - After a meaningful chunk of work, to capture spend for the report. - At session-end to persist the final tally. - Periodically during long sessions (cron-friendly — see `/loop 30m`). ## Steps 1. **Run the tracker** from the project root: ```bash node plugins/ruflo-cost-tracker/scripts/track.mjs ``` The script auto-discovers the session jsonl from the current working directory. To pin a specific session: `TRACK_SESSION=/path/to/session.jsonl`. To dry-run (no memory write): `TRACK_DRY_RUN=1`. 2. **Inspect the markdown summary** — total cost, per-model and per-tier breakdowns, and the persisted memory key. 3. **Verify persistence** — `mcp__plugin_ruflo-core_ruflo__memory_search --query "session-" --namespace cost-tracking` should list the new record. `cost-report` step 1 reads from this namespace. ## Record shape (in `cost-tracking` namespace) Key: `session-<sessionId>`. Value (JSON): ```json { "sessionId": "1dba3b8c-...", "cwd": "/Users/cohen/Projects/ruflo", "startedAt": "2026-05-04T...", "endedAt": "2026-05-05T...", "messageCount": 234, "byModel": { "claude-opus-4-7": { "tier": "opus", "input_tokens": 12345, "output_tokens": 6789, "cache_creation_input_tokens": 800000, "cache_read_input_tokens": 2000000, "messages": 50, "cost_usd": 1.23 } }, "byTier": { "haiku": 0.0, "sonnet": 0.45, "opus": 1.23, "unknown": 0 }, "total_cost_usd": 1.68, "capturedAt": "2026-05-05T..." } ``` ## Pricing source of truth The script's `PRICING` constant mirrors REFERENCE.md "Model pricing (USD per 1M tokens)". Update both together when prices change. Cache-write tokens are billed at `cache_write` rate; cache-read tokens at `cache_read` (per Anthropic billing docs). ## Env overrides | Env | Default | Purpose | |---|---|---| | `TRACK_CWD` | `process.cwd()` | Override which project's sessions to scan | | `TRACK_SESSION` | most-recent jsonl | Pin a specific session file | | `TRACK_OUT` | unset | Also write the JSON summary to this path | | `TRACK_DRY_RUN=1` | unset | Skip the `memory store` call | | `TRACK_QUIET=1` | unset | Suppress markdown output | | `TRACK_NAMESPACE` | `cost-tracking` | Override target namespace | ## Cross-references - `cost-report` (consumer) — reads records produced by this skill - REFERENCE.md "Cost attribution formula" — the math the script implements - `cost-budget-check` (consumer; landing in P2) — reads totals to evaluate alerts