The Driftproof receipt for grilling on Claude Haiku 5.5, from Report 018, dated 2026-11-02, and what it can say.
grilling on claude-haiku-5-5
Regressed
A case separated downward under the band rule. That is a separation detected under the rule, not proof that the skill moved the score.
Skill token cost: +663 input and +301 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.569 | ± 0.156 | 3 |
| without the skill | 0.542 | ± 0.181 | 3 |
Lift +0.027, ± 0.239. A spread is the sample standard deviation of the per-case means: a descriptive spread with no coverage probability. The verdict above reads each case's two bands, not these aggregates.
This receipt also reads the skill against a same-length placebo. Report 018 shows that reading.
What was verified
receipt_hash verified when this page was built from receipts/report-018/campaign-3/6911cfc88cf2c6e8ef619b12fa5c82af02bc4eb5c303230bf30cba2eb9551fc8.json; run.transcripts records retained-local.
Receipt hash: 3e658346c86911686393b4cba84299311be780e63388ccf6084e8611bcddb960
Check this file yourself
validate shows that this file is unchanged since it was sealed. It does not show who made it or who sealed it.
curl -fsSLO https://raw.githubusercontent.com/driftproofhq/driftproof/main/receipts/report-018/campaign-3/6911cfc88cf2c6e8ef619b12fa5c82af02bc4eb5c303230bf30cba2eb9551fc8.json
npx driftproof@0.27.0 validate 6911cfc88cf2c6e8ef619b12fa5c82af02bc4eb5c303230bf30cba2eb9551fc8.json