The Driftproof receipt for improve-codebase-architecture on Claude Haiku 5.5, dated 2026-11-08, and what it can say.
improve-codebase-architecture 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: +1268 input and +140 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.694 | ± 0.168 | 3 |
| without the skill | 0.611 | ± 0.142 | 3 |
Lift +0.083, ± 0.220. 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.
What was verified
receipt_hash verified when this page was built from receipts/which-section/improve-codebase-architecture/compare-B-3c42e2155cb6c63bebdd50471de6df5de4074ab9b617bb0c649b04cd6c35b4e1.json; run.transcripts records hashes-only.
Receipt hash: 3c42e2155cb6c63bebdd50471de6df5de4074ab9b617bb0c649b04cd6c35b4e1
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/which-section/improve-codebase-architecture/compare-B-3c42e2155cb6c63bebdd50471de6df5de4074ab9b617bb0c649b04cd6c35b4e1.json
npx driftproof@0.28.0 validate compare-B-3c42e2155cb6c63bebdd50471de6df5de4074ab9b617bb0c649b04cd6c35b4e1.json