The Driftproof receipt for prototype on Claude Sonnet 5.5, dated 2026-11-01, and what it can say.
prototype on claude-sonnet-5-5
Passing
A case separated upward under the band rule. That is a separation detected under the rule, not proof that the skill moved the score.
Skill token cost: +950 input and +294 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.887 | ± 0.113 | 3 |
| without the skill | 0.401 | ± 0.149 | 3 |
Lift +0.487, ± 0.187. 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 017 shows that reading.
What was verified
receipt_hash verified when this page was built from receipts/report-017c/campaign-1/ac1962e75ff73f58d89fc1dc2259ec6474c61082a1ddc3c7f1fbb78325f0cee9.json; run.transcripts records retained-local.
Receipt hash: 2026a8968d1a5ae85d33c02e634987021b04edd9ba568a9e1d2436f56621ab89
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-017c/campaign-1/ac1962e75ff73f58d89fc1dc2259ec6474c61082a1ddc3c7f1fbb78325f0cee9.json
npx driftproof@0.27.0 validate ac1962e75ff73f58d89fc1dc2259ec6474c61082a1ddc3c7f1fbb78325f0cee9.json