Write, review, and validate Starlark — the small deterministic Python dialect (go.starlark.net runtime) embedded in kitsoki as the `host.starlark.run` glue capability. Use when authoring or debugging a `.star` glue script for a kitsoki story (the `main(ctx) -> dict` contract, the `.star.yaml` sidecar, `ctx.inputs`/`ctx.world`/`ctx.http`, HTTP cassettes), embedding the Starlark interpreter in Go (Thread, FileOptions, custom Value types, exposing Go builtins), choosing a validation toolchain (buildifier / starcheck / starlark CLI / `kitsoki test flows`), or diagnosing a "this is valid Python but errors in Starlark" surprise (strings aren't iterable, no while/recursion/classes/exceptions, globals can't be reassigned).