Keep candidate object inspection offline

docs/internal/validation.md

@@ -16,6 +16,11 @@ candidate contents; the default Go-only path does not enumerate the tree.
 lazily, and resolves destinations without consulting the worktree or
 neighboring files.
 
+Committed-tree metadata and blob reads disable lazy fetching and Git transports
+for those child commands. Missing local objects produce inspection errors;
+source preparation retains its separate network-capable operations. See Git's
+[lazy-fetch controls](https://git-scm.com/docs/git) for the command mechanism.
+
 ## Adding a shared check
 
 When an optional check is accepted for implementation: