dsh-idle-compactor

The built-in auto-compaction in DeepSeek Harness recognises exactly two triggers: request pressure and a provider-confirmed context overflow. It never asks how long a session has sat quiet. So you let an agent grind through a long task, the session balloons past a hundred thousand tokens, you step away, and when you come back every single request is still paying for that stale tail while the built-in system remains completely oblivious to the idle bloat.

dsh-idle-compactor fills that missing axis. On a fixed sweep interval (30 s by default) it walks every live agent in the process and acts only when a session clears every guard simultaneously: idle past a configurable quiet window, both totalTokens and surfaceTokens above a token floor, no outstanding background jobs, no live descendant still in flight, cooldown elapsed, and not archived. Requiring both pressure and surface matters because a freshly compacted session still reads high on the pressure anchor while its actual compactable area is tiny; re-summarising it would burn detail to reclaim almost nothing, so the plugin simply skips it. The entire artefact is a single self-contained ESM patch file with zero runtime dependencies; mount it on a profile and it is live, no build script required.

You will benefit most if you run long-running agent workflows where sessions routinely go quiet for hours, or if you are on the minimal preset, which ships no compaction backend at all. Beyond adding idle compaction, the plugin re-enables a host-plane backend so sessions that previously had no way to be compacted are now covered, giving even the leanest configurations a working safety net.