# Dan's Notebook
> Technical notes on agents, systems, and software. Built in public by Dan Treasure.

## About
Dan Treasure is a content creator and technical consultant based in Michigan. He builds software tools and writes about agents, LLM cost optimization, and developer infrastructure.

## Posts
- [Building a Philosophy Quiz That Shows Its Work](https://dansnotebook.com/posts/building-a-philosophy-quiz) — 2026-03-29 — The Millerman quiz hides its scoring and gates results behind email. whothinkslikeyou.com uses fiction narratives, transparent scoring, and real exemplars instead. 8 ADRs, 120 per-question takes, 30 exemplars, $6/mo stack.
- [Can You Build a Futures Market for GPU Compute?](https://dansnotebook.com/posts/gpu-spot-price-volatility) — 2026-03-29 — gpu-spot.com scrapes Vast.ai and TensorDock every 30 minutes, runs a daily Claude-powered analysis, and tests whether GPU spot price spreads can support a futures order book. 8 GPUs, 2 platforms, explicit viability thresholds, and a 3-phase Agent SDK pipeline.
- [Harness Engineering with NixOS, Terraform, and OrbStack](https://dansnotebook.com/posts/nix-terraform-harness-engineering) — 2026-03-06 — OpenAI calls it harness engineering — designing environments where agents do reliable work. What that looks like for a solo developer using NixOS, Terraform, OrbStack, and Claude Code instead of Codex.
- [Building an Automated Bug Investigation Agent with Claude](https://dansnotebook.com/posts/building-an-investigation-agent) — 2026-02-28 — From bug report to 60-page PDF in an hour. A 7-agent pipeline with 41 skills and 14 MCP tools, built on the Claude Agent SDK. Architecture, performance optimization, and deployment on Cloud Run.
- [Prompt Caching Is Everything: Applying Claude Code's Lessons to a Multi-Agent Investigation Pipeline](https://dansnotebook.com/posts/prompt-caching-is-everything) — 2026-02-21 — Auditing a 7-agent Claude pipeline against prompt caching best practices. 85% → 98.7% cache hit rate, accurate cost tracking, and the system prompt split that made it possible.

## Projects
- [whothinkslikeyou.com](https://whothinkslikeyou.com) — Philosophical diagnostic quiz. Pick a fictional story, answer 10 questions, see how your answers map to real philosophical traditions. Transparent scoring, exemplar-based results, $6/mo stack. (Live)
- [Claude Code Video Review](https://review.dansnotebook.com) — Presenter notes, demo plans, and production tracking for the StormWind Studios Claude Code series. 122 videos across 4 courses.
- [10kdiff](https://10kdiff.com) — Financial comparison tool for SEC filings. AI-surfaced earnings comparisons across quarters. (In progress)

## Contact
Site: https://dansnotebook.com