What it is
Compaction now records when a hook fully replaced Claude Code's own summarization logic
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.267.
Presence across releases
0The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
First cited
1The earliest release whose published evidence quoted tengu_compact_replaced_by_hook was v2.1.267, 9 Sep 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table above.
Gate readings
0No release here has a gate table behind it for this flag. Most published releases have none at all: the readings exist only for versions the pipeline captured flag state on.
Names beside it
Every feature flag in the inventory starting tengu_compact, up to twelve of them.
tengu_compactAutomatic conversation compaction now flags when foreign or teammate content is being summarized never mined
tengu_compact_cache_prefixNo description from anybody. v2.1.138
tengu_compact_line_prefix_killswitchNo description from anybody. never mined
tengu_compact_preserved_unanchoredTranscript saving and cleanup logic is consolidated in one place; nothing changes for you. never mined
tengu_compact_streaming_retryNo description from anybody. never mined
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the feature flag does. All feature flags.