Trellis

the human writes the spec; the agent writes the Soil

Trellis is a specification layer, toolchain, and IDE for programs whose implementations are written by AI agents. Soil is the target language it lowers to: a small, strict, refinement-typed ML with effect tracking — the assembly language of vibe-coding, designed to be easy for a machine to write and easy for a checker to verify, read by humans but rarely written by them.

The thesis: if an agent writes the implementations, the human-authored layer should consist of prose specifications, types, tests, and structural constraints. Humans write .tr files; an agent lowers each definition to Soil under the supervision of a type checker, a refinement checker, and the tests; a per-definition lock file records the hashes, provenance, and trust status of everything. Nothing that affects correctness exists only in an agent's context.