The task's original premise was wrong and is recorded rather than
deleted. It was written to prescribe one task per session; measurement
says the variable is context, not turn count.
Measured:
- compaction cut context 27x (542,991 -> 19,974) and cost/turn 3.1x;
the 202 turns after C1 cost less than half the 136 before it
- a turn costs $0.010 at 20k context and $0.270 at 540k
- break-even for a compaction is 2-11 turns, so: compact whenever
context exceeds ~300k and work remains
- a fresh session is NOT free -- cold start floors at ~51k and must
then re-read the artifacts a compact summary already holds (~66k).
Prefer compaction to continue work; prefer a fresh session when the
task changes, because then prior context is pure overhead.
cb-cost now emits SH-1..SH-3 so the targets come from the instrument
rather than from analysis, per InnerLoop v1.1. All three are UNMET
(mean context 232,982 vs 200,000; p90 492,042 vs 300,000; batching 7.8%
vs 20%) and are reported unmet rather than retargeted -- retargeting in
the commit that first measures is precisely what T07 exists to prevent.
Eighth error instance found while writing this: CB-WP-0001's claim that
"0 of 330 tool calls were batched" is wrong. 330 was the count of
single-call responses, not the total; 31 responses batched, covering 76
calls. It was carried into this workplan unverified. Trusted-arithmetic
class -- the one the T01 audit flagged as having no executable defence,
confirming that finding within hours of making it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Collector per ADR-0003: enumerates every transcript including the
subagents/ tree, dedups by requestId, prices per model and per cache
TTL, attributes on (prev_commit, this_commit] intervals, and reconciles
to the cent or aborts.
The positive control caught a real defect on its very first run against
real data, which is the entire argument for writing it:
CA-02 assumed usage is identical across the lines of one requestId.
True in the main transcript (206/206 groups, verified twice — by the
survey and by the adversarial reviewer). FALSE in the subagents/
tree, where output_tokens is a running count: one response reads
5, 5, 195 across its three lines. First-wins scored it at 5.
So CA-02 now splits: input-side counters are charged once and must be
identical (assertion retained); output_tokens resolves to the max
(CA-02a). AC-9 pins the exact 5,5,195 case as a regression test.
The acceptance target moved again as a result, for the third time:
$248.46 -> $92.21 -> $92.87 -> $93.32. AC-1 was computed by the same
first-wins method the tool just disproved, so the tool failing its
target was the tool being correct. Target updated, not the tool.
Measured at the pin: $92.21 main + $1.11 subagent = $93.32, residual
$0.000000. 32.5% UNATTRIBUTED, reported as its own line per CA-10.
make cost / cost-test / cost-pin wired; cost-test added to `make all`
and to CI, where it gates the collector's assertions without needing
transcripts present.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
