AC-1 $93.32 ($92.21 main + $1.11 subagent), residual $0.000000. No
unmeasured rows. Composition: 88.0% cache, 11.9% output, 249:1 context
re-read to text written.
The question that could not be answered before: what /compact costs.
The transcript records it directly — 542,991 -> 19,974 tokens, a 27x
reduction. Cost per turn fell from $0.457 (136 turns before) to $0.149
(202 turns after). The 202 post-compact turns cost less than half the
136 before them.
This qualifies CB-WP-0003 T04: sessions are bounded-quadratic, not
quadratic. Cost grows with context between compactions and resets at
each one, so the failure mode is a long UNCOMPACTED session. Whether a
fresh session beats a compaction is now measurable, and T04 should
measure it before prescribing one task per session.
Stale $0.66/$92.87 targets updated across survey and workplan.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
tegwick
c0eef604e8