Programmable geometry is the easy half
essay · September 2026Design-as-code makes the geometry a program. The layer that decides whether it holds is provenance — which numbers other numbers depend on, read out of four unfinished machines.
Writing
Writing
Occasional field notes — on engineering, economics, and the places they collide.
Cowell and Encke: the same physics, different error budgets
essay · August 2026The two classical ways to integrate an orbit — what each is good at, what each costs, and where the crossover sits, measured rather than asserted.
AI in Systems Design, Part 3
essay · August 2026Parts 1 and 2 were one machine; this is five. What the method costs — where the time goes, and which instrument catches which class of error.
Building an LLM Wiki, Part 3
essay · August 2026An agent that runs commands on your laptop runs them as you. Putting it in a container — and the one hole you can decline to punch.
Giving Claude a cloud-architecture library, Part 1
essay · August 2026A general model gives you plausible architecture. Connecting a curated, opinionated library over MCP changes where the conversation starts.
Giving Claude a cloud-architecture library, Part 2
essay · August 2026What is actually in 442 files, who decided any of it, and where it is weakest — including the parts I would rather not advertise.
Giving Claude a cloud-architecture library, Part 3
essay · August 2026From answers in a chat window to documents somebody acts on — decision records, design reviews, runbooks, and a diagram that carries its provenance.
AI in Systems Design, Part 2
essay · August 2026How a design travels. A folder of correct files is not a design — and putting them on one page found problems the folder had been hiding.
AI in Systems Design, Part 1
essay · July 2026A reaction-wheel inverted pendulum designed almost entirely by a language model — what it produced, how fast, and where it stopped being reliable.
Building an LLM Wiki, Part 1
essay · July 2026The pattern, the plumbing, and the discipline that keeps a language-model-maintained wiki honest.
Building an LLM Wiki, Part 2
essay · July 2026The additions beyond Karpathy’s gist — schema-as-code, computed staleness, contradictions as data, and a retrieval test harness.
The missing fitness function
essay · July 2026On leaving NASA — what I’d taken for the summit of human spaceflight — and the question it couldn’t ask.