A vx.config.ts can import a preset, compute a command, read a constant from another file. The cache key sees the evaluated object, so all of that participates in the key. Static JSON tools cannot see it at all.
A vx.config.ts is a module: it can import a preset, spread it, compute a command. That one choice removes Turborepo's globalDependencies and Nx's namedInputs from the schema, because a language that composes does not need a schema that does.
Configs are programs and programs can read the environment. vx lock evaluates every config now and writes the resolved objects to a lockfile; vx run --frozen uses them without evaluating; vx lock --check catches drift a byte hash cannot see.
