compact

Squeeze a session that already holds work into a secondary source, then continue with a one-line focus.

Primary vs secondary (lossy historian)

• Primary source = the live session (people who were "in the room" — full grilled/implement reasoning).
• Secondary source = the summary after compact (or a handoff doc) — a lossy historian. Useful for maneuverability; always drops some why.
• Trade-off: continue = full info + noise + limited room; compact = less noise + more room + information loss.

Harness command names differ. Canonical action is compact-with-focus. There is no docs/HARNESS-MATRIX.md.

When (same agent / same directory still owns the work)

• Need smart-zone room without a full clear (working budget ~150k — see handoff for the full phase-boundary tree).
• Cast-iron case: implement → QA on what you just built — validate, don't re-architect; keep a focused summary so QA doesn't re-explore from zero (re-explore alone is also lossy on why).
• Residual default at the bottom of the phase-boundary tree when clear/handoff/subagent don't fit.