# varve run [--varve <layer>] -- <tool> <args>
Dispatches a tool from the pinned layer with the layer identity in the environment (VARVE_LAYER, VARVE_LAYER_MANIFEST_DIGEST) so provenance tooling records which qualified set produced the output. --varve runs another installed layer without touching the pin.
The tool may be **realm-qualified** — `varve run bytecodealliance/wasm-tools -- --version` — to reach one specific provider where two realms of the composition ship the same name, including the one the pin did not choose. A bare name runs what the pin chose, never what installed last (see `varve docs composition`).