What
Claude Code keeps a record of which plugins are installed. Plugins are add-ons that extend Claude Code. Before installing a plugin, Claude Code now checks that record. If the record holds data your version of Claude Code cannot read, the install stops with the error "plugin not installed: the install records hold what this build cannot read", and it no longer goes ahead.
Why
This likely stops an older version of Claude Code from overwriting plugin records that a newer version wrote. If you see this error, the plugin records were probably written by a different version of Claude Code than the one you are running.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
What exactly makes the plugin records count as unreadable is not known.