A compaction capability family (see capability seams): a Service Definition, a summarizing provider, a model-free tool-result pruning companion, and a human command Consumer. All product packages.

Package	Role	ctx key
`compact/`	Compaction seam and event vocabulary	`ctx.compact`
`compact-basic/`	Token-pressure and summarization backend	registers `ctx.compact`
`compact-tool-result-prune/`	Optional model-free tool-result pruning	`ctx.toolResultPrune`
`command-compact/`	Human compaction command	registers on `ctx.commands`

The backend, optional pruner, and human command compose through the seam; token measurement remains a separate LLM-family service. The compaction capability-seam Agent Note owns the dependency rationale.

The subsystem reference — the compact/* events, CompactionResult, the service, pruning outcomes — is docs/subsystems/compaction.md; the seam's deliberate dsh-session/dsh-llm dependency is recorded in the compaction capability-seam Agent Note.