======================================================================
RTK ON vs OFF   results/pairs-20260805-174828
======================================================================

QUALITY  (all trials; a timed-out/errored trial = NOT passed)
  arm                    trials  errored  passed  pass-rate  mean-rwd
  OFF (stock)                20        1      17        85%     0.850
  ON  (rtk)                  20        1      19        95%     0.950
  -> pass-rate delta = +10 pp

COST & TOKENS  (MEAN over all trials with a value -- errored included)
  metric              OFF mean     ON mean      Δ%  perm-p  n OFF/ON
  Cost USD               $1.84       $1.55  -15.6%   0.411     19/19
  Input tokens       1,541,964   1,293,209  -16.1%   0.469     19/19
  Cache tokens       1,493,477   1,250,541  -16.3%   0.470     19/19
  Output tokens         24,422      20,122  -17.6%   0.344     19/19
  TOTAL spend           $34.99      $29.54  -15.6%

BASH OUTPUT  (mean per trial, from session logs; ~tokens = bytes/4)
  metric                     OFF            ON      Δ%
  bytes                   49,752        45,820   -7.9%
  ~tokens                 12,438        11,455   -7.9%

READ-OUT
  - Cost/tokens use MEAN over ALL trials, not survivor-median, so a
    clipped expensive trial can't fake a saving.
  - perm-p >= 0.05 => the delta is indistinguishable from noise.
  - Pass rate must NOT drop under ON; that's the real regression signal.
