# cost-track

Reads the session jsonl of a Claude Code run, adds up token usage per model, prices it and stores a record in the cost-tracking namespace.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 684 installs · ★ 79357
- Author: ruvnet
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/ruvnet/ruflo/tree/HEAD/plugins/ruflo-cost-tracker/skills/cost-track/SKILL.md
- Updated: 2026-10-25
- HTML: https://affpapa.org/en/nevibecode/skills/cost-track

## What it does

Give it a session and you get figures instead of guesses. The skill parses `~/.claude/projects/<encoded-cwd>/<session>.jsonl`, tallies the `usage` block of assistant messages for each model, applies the prices listed in REFERENCE.md and saves one record under `session-<sessionId>` in the `cost-tracking` AgentDB namespace. Cache writes are billed at the `cache_write` rate, cache reads at `cache_read`.

From the project root, run `node plugins/ruflo-cost-tracker/scripts/track.mjs`. The script picks the most recent jsonl for the current directory by itself, prints a markdown summary with per-model and per-tier breakdowns, then calls `memory_store`. Node.js and that MCP memory tool are what it needs. `TRACK_DRY_RUN=1` skips the write and leaves you the summary. Other switches cover the rest: `TRACK_CWD` to scan another project, `TRACK_SESSION` to pin a file, `TRACK_OUT` to dump the JSON.

The jsonl is the only source of numbers, and it sits inside the Claude Code project folder. Load the skill under Cursor or Codex and there is often nothing to read. So check the namespace after the first run, because `cost-report` and `cost-optimize` take their data from `cost-tracking` alone.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add ruvnet/ruflo --skill cost-track -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/cost-track/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/cost-track/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add ruvnet/ruflo --skill cost-track -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/cost-track/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add ruvnet/ruflo --skill cost-track -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/cost-track/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install ruvnet/ruflo cost-track
```

2. **Manually: put the files in place**
- File: `.github/skills/cost-track/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add ruvnet/ruflo --skill cost-track -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/ruvnet/ruflo --path plugins/ruflo-cost-tracker/skills/cost-track
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/cost-track/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add ruvnet/ruflo --skill cost-track -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/ruvnet/ruflo/tree/HEAD/plugins/ruflo-cost-tracker/skills/cost-track/SKILL.md

## When to use it
- find out what a finished session actually cost
- break spending down by model and tier
- keep a record of token use across projects
- see how much goes to cache writes versus cache reads
- hand real numbers to `cost-report`

## Example prompts
- Run cost-track on this session and show me the breakdown by model
- How much did opus cost us in this project? Run cost-track
- Run `node plugins/ruflo-cost-tracker/scripts/track.mjs` with `TRACK_DRY_RUN=1`, skip the memory write for now

## Source text · SKILL.md · MIT

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BEGIN THIRD-PARTY FILE 0aa3713958e9a91e
````text
---
name: cost-track
description: Auto-capture per-session token usage from the Claude Code session jsonl and persist to the cost-tracking namespace
argument-hint: ""
allowed-tools: Bash mcp__plugin_ruflo-core_ruflo__memory_store
---

# 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 |
````
END THIRD-PARTY FILE 0aa3713958e9a91e

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---
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