The Driftproof receipt for improve-codebase-architecture on Claude Sonnet 5.5, dated 2026-11-01, and what it can say.
improve-codebase-architecture 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: +2141 input and +414 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.783 | ± 0.144 | 3 |
| without the skill | 0.704 | ± 0.079 | 3 |
Lift +0.079, ± 0.165. 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-1/95d64cad7267275a0b44ec0d34324121590d1f55dff9e34ccd09b722214164e2.json; run.transcripts records retained-local.
Receipt hash: 4fba7a9b04033dee6c13a9c615ff264cc2175f10958c0a5ba1ed2aa19d4ad401
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-1/95d64cad7267275a0b44ec0d34324121590d1f55dff9e34ccd09b722214164e2.json
npx driftproof@0.27.0 validate 95d64cad7267275a0b44ec0d34324121590d1f55dff9e34ccd09b722214164e2.json