#developer-experience

TypeScript in Go, Vite on Rolldown, Biome instead of ESLint and Prettier, uv on the Python side. In eighteen months most of the tools that used to be written in the language they process were replaced by native ones. I moved a monorepo across all of them. Here is the before and after, and the two places where the rewrite is not a free win.

I moved commit messages, log triage, PR summaries, test naming and half a dozen other small jobs from a hosted API to an open-weight model running on my laptop. It was not about cost. It was about a category of task where a 30B model on a MacBook is indistinguishable from the frontier, and where I would rather the data never left the machine.

Every team that adopted MCP hit the same wall by spring: forty tools in the context, a model that picks the wrong one, and a bill that grew with every server you added. Skills, the folder-of-markdown pattern that spread through coding agents this year, fix a different problem than MCP does. Knowing which is which decides whether your agent gets better or just bigger.