Notes from the spine

Long-form on craft, on product, and on the parts where the abstraction leaks.

Working notes on building Spine. Some are for editors and writers. Some are for engineers. Filter to taste. RSS.

All notesevery post For editorscraft + product For engineerssystems + benchmarks

April 25, 20266 min readengineering
Routing model choice by surface — how we use Opus, Sonnet, and Haiku in one product
Spine routes every Claude call to the smallest model that can do the job. Here is the routing table, the reasoning, and the cost numbers.
April 22, 20266 min readeditorial
Why a novel deserves a git log
A literary critic's mental model and a senior engineer's mental model are the same shape. Spine makes that shape visible.

Notes · Spine · Spine