With the guard enabled the binary search recovers best sampling_u=0.078125
(rate 2.30 req/s), identical to the full-replay baseline. The guard fired on
exactly the one feasibility-knee probe (0.08594, re-measured full -> infeasible);
the other three probes truncated to ~45-50%. Net ~38% replay saved on the trial
with no peak-rate overestimate. Stop-A + boundary guard is safe to enable.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CPU calibration (chat vs coder) reproduces the paper's C-slowest ordering and
shows C-convergence difficulty is driven by signal noise (low-reuse chat) not
reuse magnitude. GPU fidelity check on Qwen3-30B-A3B: truncating at the L-C-A
convergence prefix saves ~52% replay (tau_c=0.90) with 3/4 probe verdicts
preserved; the one mismatch is a boundary false-positive at the feasibility knee
(prefix 0.96 vs full 0.946), caused by second-half engine-state drift the offered
L-C-A cannot see. Argues for revisiting the SLO-boundary guard before enabling.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
