⚡ Builder's Note · Sneak peek of this week's guide
Your prompt cache hit rate is leaking money.
Claude Sonnet 4.5 + prompt caching can hit 85%+ cache hit rates and save 90% on input cost — but only if your prompts are structured cache-first: stable system prompt at the top, user content at the bottom, no shuffling. Most teams have hit rates under 30% and don't know it.
→ Full cache-first prompt template + measurement script in the guide.
The Agent Stack Guide — weekly deep-dive
Patterns, postmortems, prompt templates. 30-60 min read. Saves you the 3-week production lesson.
- 1 deeply-worked architectural pattern per week (not a curated link list)
- Real postmortems from real agent ops — what broke, what fixed it
- Production-ready prompt templates with measurable hit rates
- Cost optimization audits you can run on your own stack today
Get the guide → $19/wk or $79/mo (annual: $790)