The Driftproof receipt for git-workflow-and-versioning on Claude Opus 5, from Report 009, dated 2026-09-15, and what it can say.
git-workflow-and-versioning on claude-opus-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: +5004 input and +71 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.862 | no spread recorded | 1 |
| without the skill | 0.300 | no spread recorded | 1 |
Lift +0.562, no ± (1 case). 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/report-009/git-workflow-and-versioning-claude-opus-5-2026-09-15.json; run.transcripts records retained-local.
Receipt hash: 2df794c7f2539a9ce4701a03997b667c90cef8c2136a77eabf39313df5b7af33
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-009/git-workflow-and-versioning-claude-opus-5-2026-09-15.json
npx driftproof@0.27.0 validate git-workflow-and-versioning-claude-opus-5-2026-09-15.json