# Cache Efficiency

> >

- **Type:** Skill
- **Install:** `agentstack add skill-hoangsonww-claude-code-agent-monitor-cache-efficiency`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [hoangsonww](https://agentstack.voostack.com/s/hoangsonww)
- **Installs:** 0
- **Category:** [Databases](https://agentstack.voostack.com/c/databases)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [hoangsonww](https://github.com/hoangsonww)
- **Source:** https://github.com/hoangsonww/Claude-Code-Agent-Monitor/tree/master/plugins/ccam-analytics/skills/cache-efficiency
- **Website:** https://hoangsonww.github.io/Claude-Code-Agent-Monitor/

## Install

```sh
agentstack add skill-hoangsonww-claude-code-agent-monitor-cache-efficiency
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Cache Efficiency

Diagnose whether prompt caching is actually saving money, and where it is not.

## Input

The user provides: **$ARGUMENTS**

This may be: empty (analyze the whole fleet), "today" / "this week" / a date range, a session ID to scope the analysis, or a target like "hit rate > 80%". When empty, analyze all data from `/api/analytics`.

## Data Sources

| Endpoint | Returns |
|----------|---------|
| `GET /api/analytics` | `tokens.total_input`, `tokens.total_output`, `tokens.total_cache_read`, `tokens.total_cache_write` (baselines pre-summed), plus `daily_sessions` |
| `GET /api/sessions?limit=200` | Session list — each has model, cwd, started_at, ended_at, inline `cost`, metadata (JSON: usage_extras with cache token detail) |
| `GET /api/sessions/{id}` | Full session detail with nested agents and events, for drill-down on a flagged session |
| `GET /api/pricing/cost` | `{ total_cost, breakdown: [{ model, input_tokens, output_tokens, cache_read_tokens, cache_write_tokens, cost, matched_rule }] }` — used to price cache read vs write spend |

### How cache economics work

```
cache_hit_rate   = total_cache_read / (total_cache_read + total_input)
cache_reuse      = total_cache_read / total_cache_write
cache_read_cost  = (cache_read_tokens  / 1M) × cache_read_per_mtok
cache_write_cost = (cache_write_tokens / 1M) × cache_write_per_mtok
```

Cache writes cost more per token than cache reads (e.g. Sonnet $3.75 write vs $0.30 read per Mtok), and writes are billed even if the cached block is never reused. The payoff only arrives on subsequent reads — so a healthy fleet shows **cache_read_tokens far exceeding cache_write_tokens**. When `cache_reuse 70% strong, 40–70% moderate, > cache_read`: short or one-shot sessions rarely recoup cache writes — note them.
- Stable, repeated context (system prompts, large files) should be cached once and reused; high churn defeats caching.
- Estimate the dollar impact of raising the hit rate to the next benchmark tier.

## Output

Structured Markdown with tables. Currency as USD to 4 decimal places; rates as $/Mtok; percentages with ▲/▼ for any trend. Token counts with thousands separators.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [hoangsonww](https://github.com/hoangsonww)
- **Source:** [hoangsonww/Claude-Code-Agent-Monitor](https://github.com/hoangsonww/Claude-Code-Agent-Monitor)
- **License:** MIT
- **Homepage:** https://hoangsonww.github.io/Claude-Code-Agent-Monitor/

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-hoangsonww-claude-code-agent-monitor-cache-efficiency
- Seller: https://agentstack.voostack.com/s/hoangsonww
- Browse the marketplace: https://agentstack.voostack.com/browse

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