What probably matters to youSection of the release
Unclear It is not clear whether automatic compaction ran these hooks through this same path before.
What
Compaction is when Claude Code shortens a long conversation by summarising it, so it fits in the model's memory. A hook is a command of your own that Claude Code runs at a set moment. The PreCompact hook runs just before compaction.
The trigger value the hook receives is now auto when compaction happens automatically. Before, it was always manual.
Why
A PreCompact hook can now tell the two cases apart. A hook that matches on trigger will now see auto for automatic compaction, so check any hook that expected only manual.
