The Driftproof receipt for CLAUDE.md on Claude Haiku 5.5, from Report 016, dated 2026-10-28, and what it can say.
CLAUDE.md on claude-haiku-5-5
Not enough draws
Not enough draws to conclude at this effect floor.
Draws needed: no draw count at these spreads (case binary-search-js: the two arms' spreads sum to 0.577, at or above the 0.05 floor).
Skill token cost: +67604 input and +1269 output tokens per call against no skill (measured, grading excluded).
The two arms
| arm | mean | spread across cases | cases |
|---|---|---|---|
| with the skill | 0.974 | ± 0.115 | 19 |
| without the skill | 0.947 | ± 0.229 | 19 |
No lift is stated for a state that did not measure one. 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-016/receipt-8ecb8f08cd5c.json; run.transcripts records retained-local.
Receipt hash: 8ecb8f08cd5c10b3e637e98da9ce5fab29c28ab9b65d990c9a83cc656e912c50
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-016/receipt-8ecb8f08cd5c.json
npx driftproof@0.28.0 validate receipt-8ecb8f08cd5c.json