What probably matters to youSection of the release
Unclear It is not clear what makes idle compaction happen in the first place.
What
Compaction is when Claude Code summarises a long conversation to make room. Idle compaction does this while the session (your open conversation with Claude Code) is sitting idle. There are two new controls:
idleCompaction is a new setting. Set it to false to stop Claude Code compacting a long conversation while the session is idle. It defaults to true. Setting it to true does not turn idle compaction on. When it is false, the eligibility check stops early with idle_compaction_off.
CLAUDE_CODE_IDLE_COMPACT_MIN_TOKENS is a new environment variable (a setting passed to Claude Code from your shell). It replaces the minTokens value from the tengu_sunny_locket remote config, cannot go below a minimum, and is listed among the compaction-related environment variables.
Whether idle compaction runs at all still comes only from tengu_sunny_locket. Its mode must be "log" or "compact", and without a value from the server the mode is "off".
Why
You can now refuse background compaction of an idle conversation, or change how large a conversation must be before idle compaction is considered. Neither control can turn idle compaction on where the server has not enabled it.
