Summarise this lane's conversation now
Summarises the older part of this lane’s conversation on demand, instead of waiting for the host to decide the next round no longer fits. It is the same summarisation the automatic path runs, so it costs one model round and the compaction event it publishes carries the reason manual.
Lane-scoped because a window belongs to a lane: the conversation and each delegation beside it carry their own, and the host has no opinion about which of them a session-wide gesture would mean.
The paid gesture of the pair. prune frees old tool output for nothing and destroys no reasoning; this one throws conversation away and pays a round to do it, so a client offering both should offer pruning first.
Answers 409 when a turn is running on the lane — rebuilding the window under a round in flight would race the turn that owns it — and 409 when there is nothing left to summarise. The token figure a client is showing goes UNKNOWN rather than moving: nobody can say what the rebuilt window costs until a provider counts it, so the meter refills on the next metered round.