Cost Breakdown

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 1f059c400d07 · 16 Oct 2026Report an issue or request a re-scan

• Publisherhoangsonww GitHub userOwner of the repository this skill is read from
• Source folderhoangsonww/Claude-Code-Agent-Monitor/plugins/ccam-analytics/skills/cost-breakdownThe exact folder we audited
• LicenceMITAs the repository states it
• Commit pinned for this verdict1f059c400d07A new audit runs when the source changes
• Repository statusNot archivedLast push 4 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Break down Claude Code costs using the Agent Monitor pricing engine. Shows per-model costs (input, output, cache_read, cache_write at $/Mtok rates), per-session costs, daily trends, and compaction baseline token…

---
name: cost-breakdown
description: >
  Break down Claude Code costs using the Agent Monitor pricing engine.
  Shows per-model costs (input, output, cache_read, cache_write at $/Mtok rates),
  per-session costs, daily trends, and compaction baseline token recovery.
  Use when analyzing spending, comparing model costs, or planning budgets.
---

# Cost Breakdown

Detailed cost analysis from the Agent Monitor's pricing engine.

## Input

The user provides: **$ARGUMENTS**

This may be: "today", "this week", "last 30 days", a session ID, or "budget $50/week".

## Data Sources

| Endpoint | Returns |
|----------|---------|
| `GET /api/pricing` | `{ pricing: [{ model_pattern, display_name, input_per_mtok, output_per_mtok, cache_read_per_mtok, cache_write_per_mtok }] }` |
| `GET /api/pricing/cost` | Total cost: `{ total_cost, breakdown: [{ model, input_tokens, output_tokens, cache_read_tokens, cache_write_tokens, cost, matched_rule }] }` |
| `GET /api/pricing/cost/{sessionId}` | Per-session cost with same breakdown shape |
| `GET /api/sessions?limit=200` | Sessions list — each includes inline `cost` field (bulk pricing) |
| `GET /api/analytics` | Token totals (total_input, total_output, total_cache_read, total_cache_write — baselines pre-summed), daily trends |

### How costs are calculated

The pricing engine matches model names against `model_pattern` using SQL LIKE (e.g. `claude-sonnet-4-5%` matches `claude-sonnet-4-5-20250514`). **Longest pattern wins** for specificity. Cost per model:

```
cost = (input_tokens / 1M) × input_per_mtok
     + (output_tokens / 1M) × output_per_mtok
     + (cache_read_tokens / 1M) × cache_read_per_mtok
     + (cache_write_tokens / 1M) × cache_write_per_mtok
```

Token counts are **effective totals** = `current + baseline` (baselines preserve pre-compaction tokens that would otherwise be lost when the transcript JSONL is rewritten).

### Default pricing tiers (seeded on first run)

| Family | Input $/Mtok | Output $/Mtok | Cache Read $/Mtok | Cache Write $/Mtok |
|--------|-------------|--------------|-------------------|-------------------|
| Opus 4.5/4.6 | $5 | $25 | $0.50 | $6.25 |
| Sonnet 4/4.5/4.6 | $3 | $15 | $0.30 | $3.75 |
| Haiku 4.5 | $1 | $5 | $0.10 | $1.25 |

## Report Sections

### 1. Cost by Model
Table from `/api/pricing/cost` breakdown — each model with 4 token counts + cost. Highlight which pricing rule matched.

### 2. Cost by Session (Top 10 Most Expensive)
From sessions list with inline `cost` — sort descending. Show session name, model, duration, cost.

### 3. Daily Cost Trend
Cross-reference `daily_sessions` with per-session costs to compute daily spend. Show 7/30-day trend with direction arrows.

### 4. Token Efficiency Analysis
- **Cache hit rate**: `total_cache_read / (total_cache_read + total_input) × 100` — higher = more efficient
- **Compaction baseline recovery**: Tokens preserved via baseline columns (tokens not lost to compaction)
- **Output/input ratio**: Balanced ratio indicates good prompt efficiency

### 5. Cost Optimization Opportunities
- Sessions where cache_write >> cache_read (poor cache reuse)
- Expensive models used for simple tasks (check subagent_type vs model)
- Sessions with many compactions (context overflow = wasted tokens)

## Output

Structured Markdown with tables. Currency as USD to 4 decimal places. Include total and per-model subtotals.

Excerpt, first 3,378 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

1. 2026-10-16
   ✓SAFE B 89 / 100

   first audit · source 1f059c400d07

Questions about Cost Breakdown

• github.com/hoangsonww/Claude-Code-Agent-Monitor/tree/master/plug — the audited source at commit 1f059c400d07 and every finding aboveObserved · 16 Oct 2026

Spotted something wrong? Report a correction · Methodology