The Driftproof receipt for handoff on Claude Sonnet 5.5, dated 2026-11-01, and what it can say.
handoff on claude-sonnet-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: +310 input and +230 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.766 | ± 0.039 | 3 |
| without the skill | 0.804 | ± 0.109 | 3 |
Lift -0.039, ± 0.116. 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-1/335148930bb21ee4a130cc0964044930eb0c9f845dc4c35d918dd876343c4bed.json; run.transcripts records retained-local.
Receipt hash: c99347fd5003d4ce8f8af82defa7c3480943b1d348dc35c73845f59cf9776258
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-1/335148930bb21ee4a130cc0964044930eb0c9f845dc4c35d918dd876343c4bed.json
npx driftproof@0.27.0 validate 335148930bb21ee4a130cc0964044930eb0c9f845dc4c35d918dd876343c4bed.json