fz

What it is

fz.

fz links against your venture's compiled-in harness and runs as a bin target inside the venture repo, which is the pattern the venture template ships. That is not packaging preference: a migration collector that guessed at your module list would collect the wrong migrations, and a doctor that guessed at your ports would pass a venture that cannot boot.

fz migrations collect walks the modules in config order and writes files named so that wrangler d1 migrations apply executes them in the right order. The lock file is the part that matters: migrations/.harness-lock.json pins each module/migration-id to its global file name plus a sha256 of its content, so a migration edited after it shipped is a failure rather than a silent divergence between two databases.