Records the sweep over every A/B log on this machine (103 sessions, 297
explore calls, 0 crashes) and, more usefully, the new-vs-baseline arm
table the metric exists for: express 82% → 100%, cg21/client-go 67% →
95%, two pairs going the other way.
States the caveat in the places it can be misread: the corpus median sits
in the eighties because these are flow questions whose answers name most
of the chain, the metric is byte-weighted, and an agent can use a file
without citing it. It compares two builds on one question; it is not an
absolute waste figure.
CG-21 fixed the unspent-reservation defect and re-ran the A/B itself. CG-22 is
the gate proper: CG-15's setup, unchanged, measured independently of the task
that wrote the fix. RUNS=3, both arms codegraph-on, sonnet/high,
CODEGRAPH_NO_PROMPT_HOOK=1 on both, baseline pinned to 49c11fc by SHA, fresh
clones of the same three repos and the same three questions.
All four bars pass. Read = 0 in all 12 new-arm runs (express 3, excalidraw 3,
client-go 6) while the baseline reads in 3 of 3 express runs and 1 of 6
client-go runs; the express run that failed CG-15 with 4 Reads of lib/utils.js
now reads nothing and receives the file whole. Answer share >= 66.6% in every
new run. Medians: express 26s -> 24s, excalidraw 26s -> 26s, client-go
35s -> 36.5s at n=6 with fully overlapping ranges.
Deterministic core re-measured on BOTH builds in one session rather than
quoted: lib/utils.js renders whole at 6,380 B on baseline and on HEAD (583 B
stub under CG-12), and the source envelope goes 13,849 -> 14,913 against an
unchanged 13,000 budget, so the reservation is spent and the envelope stops
shrinking. client-go's +1.5s median is attributed away from the build: explore
latency 669 vs 668 ms (n=5) and the new build's deterministic response is both
smaller (15.8K vs 18.9K) and more concentrated (top file 50.2% vs 35.7%).
Two counter-points recorded as measured, not smoothed: excalidraw's new arm
runs below its baseline on answer share (66.6-81.9 vs 75.5-92.7, all well over
the bar), and this session's client-go baseline sampled well (85.6-100%), so
the #1500 gap is smaller here than in CG-21's session.
CHANGELOG: the two #1500 bullets were multi-sentence paragraphs carrying
implementation detail. Rewritten to house style as four bullets that lead with
the symptom, with the mechanism, the banner catalogue and the old-behaviour
contrast dropped; the @LeDuyViet credit and the re-index note stay.
Suite green on the measured build: 171 files, 2,868 passed, 6 skipped.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Re-runs CG-15's agent A/B on the fixed build: same harness, same three
prompts, same baseline ref, n=6 per arm on express and excalidraw.
Read = 0 in all 15 new-arm runs. The express regression that routed the
defect to CG-21 does not reproduce in 6 attempts, and the baseline now
reads in 4 of 6 while the new arm reads in none (median 24.5s -> 21.5s),
so the control beats the arm it previously lost to. client-go holds
92.7-96.2% answer share against a baseline run at 53.8%.
Excalidraw's new arm is ~8s slower at the median and that is recorded as
NOT attributable to the build rather than waved through: explore's own
latency is 374ms vs 372ms on the same query and index, the deterministic
responses differ by +2% with one byte-identical, and the unchanged main
build's own median moved 34s -> 26.5s between the two sessions — the same
magnitude as the gap.
Bars were not re-baselined; they are CG-15's four, applied to a larger
sample. The CG-15 section is kept intact and marked superseded, because
its root-cause analysis is the record of why the fix looks like it does.
Three repos, both arms codegraph-on, sonnet/high, 3 runs per arm.
PASS on the two medium repos: client-go (the reporter's Go shape, 2,001 of
2,454 files generated) and excalidraw hold Read 0 in every run of both arms,
excalidraw goes 34s -> 24s at the median with one fewer explore call, and the
generated clientsets/informers that took 10.5%% of a baseline envelope appear
in no new run.
FAIL on express, the small control, in 1 run of 3: 4 Reads and 52s against a
baseline that read once. Not agent variance — replaying that run's query
deterministically, lib/utils.js goes from 6,380 bytes whole to a 583-byte
cluster stub and the envelope shrinks 13.8K -> 9.2K against an unchanged
13,000 budget. The diagnostic shows the allocator was right and the render
loop was not: utils.js is the top-ranked file, was reserved 3,870 chars, and
spent 583. The whole-file bound (allowance + grace = 4,450) lands just under
the file's 5,293 bytes, so the whole-file render is declined and the unspent
reservation is dropped rather than redistributed.
Bar 1 is the hard gate, so per CG-15's acceptance rule the design goes back to
CG-12 — the budget is not to be widened to compensate. Two candidate fixes are
written up in the design doc.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Colby McHenry
