Madness Driven Design: Don Quixote, Sancho Panza, and Your AI Copilot

TL;DR: An LLM is like Don Quijote—you can’t cure his madness, it’s stochastic by nature. The solution isn’t to fix the madman but to assign him a deterministic Sancho Panza as a sidekick. MDD consists of two layers: first, you study the errors it makes to design tools that absorb those mistakes, and then you let it loose with those tools to verify you’ve closed any gaps. Design for madness, not against it. ...

March 26, 2026 · Fernando

Why My CLI Output Isn't XML (And How I Ended Up Reinventing TOON Without Knowing It)

TL;DR: When your primary consumer is an LLM, XML and JSON waste tokens by repeating structure in every element. A compact positional format reduces consumption by 50%. Turns out this idea already had a name: TOON (Token-Oriented Object Notation). Same selective pressure — expensive tokens and repeated keys — same solution. Anthropic uses XML for everything. Their system prompts are wrapped in <instructions>, their examples in <example>, their tools in <function>. If you work with Claude, you live surrounded by tags. ...

March 26, 2026 · Fernando

Summoning the Wise: How to Use an LLM as a Mentoring Session with Any Expert

My wife summons Charlie Munger to plan our family budget. In ChatGPT. I’m not joking. She tells it something like “act as Charlie Munger reviewing our family finances” and feeds it our monthly expenses. The thing returns insights like “you’re confusing investment with expense in the education category” or “that fund has a hidden cost you’re not accounting for.” Things Munger would say. With the tone Munger would use. I did the same thing. But instead of an investor, I summoned a different expert: Edward Tufte. ...

February 18, 2026 · Fernando