dmitryprg-ai/cache-analysis

Cache Analysis

Measure and optimize prompt cache performance using claude-cache-analyzer. Cache efficiency directly impacts cost — a 95% hit rate saves ~80% vs no caching.

Prerequisites

pip install claude-cache-analyzer

Quick Analysis

# All recent sessions
claude-cache-analyzer "C:\Users\Divan\.claude" --top 10

# Specific project
claude-cache-analyzer "C:\Users\Divan\.claude\projects\PROJECT_DIR" --top 5

# Grouped by project
claude-cache-analyzer "C:\Users\Divan\.claude" -g

# Export to JSON for programmatic analysis
claude-cache-analyzer "C:\Users\Divan\.claude" --export-json metrics.json

# Detailed single session
claude-cache-analyzer -s SESSION_ID

Key Metrics

| Metric | What It Means | Good Value | |--------|---------------|------------| | Cache hit rate | % of tokens served from cache | > 80% | | Efficiency score | Overall cache utilization [0..1] | > 0.70 | | Net savings | Money saved minus cache write overhead | Positive | | Savings % | Cost reduction vs no-cache baseline | > 70% |

Performance Grades

| Grade | Efficiency Score | Action | |-------|-----------------|--------| | A | >= 0.70 | Excellent — no changes needed | | B | >= 0.50 | Good — minor optimization possible | | C | >= 0.30 | Fair — review instruction structure | | D | >= 0.10 | Poor — rules/skills may be too dynamic | | F | < 0.10 | Critical — architecture needs rework |

Optimization Tips

If cache efficiency is low, the cause is usually rules or context that change too frequently between turns:

1. Move volatile content to references/ — only loaded when needed, not cached in every turn
2. Keep SKILL.md stable — frequent edits invalidate cache across all sessions
3. Use path-scoped rules — rules loaded for specific files don't pollute the cache for unrelated work
4. Prefer agent-decided rules over always-loaded — reduces base context size

Why This Matters

Cache efficiency = cost efficiency. On this project, 95% hit rate saves ~$119 per session. A drop to 50% would triple the cost. Monitoring cache performance catches regressions from rule/skill changes before they become expensive.