The Driftproof receipt for prototype on Claude Haiku 5.5, from Report 018, dated 2026-11-02, and what it can say.
prototype on claude-haiku-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: +947 input and +645 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.740 | ± 0.099 | 3 |
| without the skill | 0.342 | ± 0.116 | 3 |
Lift +0.398, ± 0.152. 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/b0b2f8a1ac34754b4496340afafaee588c18fb54fb89ec6b2f577a26db672fd6.json; run.transcripts records retained-local.
Receipt hash: 40160d77f9e761754f7c41703fcadaf31424dd6d7c8fc0291991bb08c14d5fbb
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/b0b2f8a1ac34754b4496340afafaee588c18fb54fb89ec6b2f577a26db672fd6.json
npx driftproof@0.27.0 validate b0b2f8a1ac34754b4496340afafaee588c18fb54fb89ec6b2f577a26db672fd6.json