What's not built yet
The whistle MCP server, shep serve, shep dev and shep runtime, .js Flockfiles, a CLI-flag config layer, openrc and BSD rc.d units, and Windows entirely — the full list, including what's held back past 1.0 on purpose.
This page hasn't been written yet.
The material exists in the repo under docs/specs/deferred.md. It gets a real page here before 1.0.