Hook scripts in .slam/hooks/ are executed at each stage of the build pipeline. If a script exists and is executable, it runs; a non-zero exit stops the build. Available hooks: pre_format / post_format pre_install / post_install pre_test / post_test pre_build / post_build The init command now creates .slam/hooks/ with a README documenting usage and examples, and includes a default pre_format hook that initializes any git submodules that are present.