Preflight comparison transaction names

docs/internal/comparison-publication.md

@@ -21,6 +21,12 @@ For replacement, it moves the prior bundle to a private sibling backup,
 reauthorizes that moved entry, and restores it if installing the new bundle
 fails.
 
+Planning also validates the final component and the bounded fixed names used
+for private staging and backup siblings. A destination that cannot form those
+names is rejected before publication creates a missing parent directory; a
+maximum-length valid destination remains usable because transaction siblings do
+not incorporate its basename.
+
 The new bundle is committed only after the staged directory has been installed
 at the target. From that point its artifact paths are authoritative: a failure
 to remove the retained sibling backup does not roll back the new bundle.

docs/operations.md

@@ -126,6 +126,9 @@ directories, symlinks, and unsafe destinations are rejected. Cancellation and
 all failures before publication preserve an existing bundle. Profile failures
 are different: the command publishes a complete partial bundle, with failed
 profiles represented in the manifest and no Markdown file for those profiles.
+Comparison preflight also checks that private publication siblings can be
+formed. An infeasible destination name is rejected before a missing parent
+directory is created.
 
 ## Local Prompt Profile Override