cost-analysis

name	cost-analysis
description	Analyze Claude Code session costs using ccusage. Shows token distribution, per-model breakdown, cache efficiency, and optimization recommendations.
argument-hint	["session|daily|auto"]

Cost Analysis

Analyze Claude Code token usage and costs for the SOLAR LINE project.

Quick Usage

Auto-detect (requires bun + ccusage):

cd ts && node --experimental-strip-types src/analyze-costs.ts --mode auto

Manual with ccusage pipe:

export PATH="$HOME/.bun/bin:$PATH"
bunx ccusage@17 session --offline --json --timezone Asia/Tokyo | \
  node --experimental-strip-types ts/src/analyze-costs.ts --mode session

Daily summary:

export PATH="$HOME/.bun/bin:$PATH"
bunx ccusage@17 daily --offline --json --timezone Asia/Tokyo | \
  node --experimental-strip-types ts/src/analyze-costs.ts --mode daily

What It Reports

1. Token Distribution: Input, output, cache creation, cache read breakdown
2. Per-Model Costs: Opus, Sonnet, Haiku token and cost breakdown
3. Session Efficiency: Main vs subagent costs, expensive sessions, cache hit rates
4. Recommendations: Actionable suggestions for reducing context waste

Key Metrics to Watch

Metric	Good	Needs Attention
Cache hit rate	>95%	<90%
TodoWrite % of calls	<5%	>10%
Subagent avg tokens	<500K	>1M
Max session size	<2MB	>3MB

Installation Note

ccusage v18+ requires the runtime: protocol (bun-native). Use v17:

bunx ccusage@17 [command] --offline --json

If bun is not installed:

curl -fsSL https://bun.sh/install | bash
export PATH="$HOME/.bun/bin:$PATH"

See Also

• ideas/cost_efficiency_analysis.md — Full analysis write-up
• CLAUDE.md "Context Efficiency" section — Operational guidelines