Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
CompactionArea: what it touches
Internal ChangesKind: in v2.1.323,
Internal ChangesSection of the release
What
When a conversation grows too long, Claude Code compacts it, which means summarising earlier parts to free up space. The prompt used for that step carries its own copy of the Workflow tool's description. In that copy, the two lines about ultracode now describe its confirmation as "a message from the system" instead of "a system-reminder". Ultracode is triggered by typing the keyword "ultracode" in your prompt.
Why
Changing Claude's instructions can change how it behaves. Here only the name for the confirmation message changed.
