mandela

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Translated

Audit any eval, metric, experiment, or benchmark for leakage — does external ground-truth enter independently, or are the model, scorer, and designer just confirming a result no outside truth ever produced? Use before trusting any 'how we'll know it worked' — an A/B, a holdout, a score, a validation — and whenever a result feels too clean or self-confirming. Walks an 8-pattern leakage taxonomy and returns only the patterns that fire, each with an independence fix. Read-only.

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Sourcelilmgenius/paperthin

Added on2026-07-07

NPX Install

npx skill4agent add lilmgenius/paperthin mandela

SKILL.md Content

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Audit a validation for leakage: does outside ground-truth actually enter, or is everyone confirming a result no one independently produced?

Goal

The name is the Mandela Effect — a whole population confidently remembers something that never independently happened; a leaky validation is the same shape. Walk the 8 patterns below.

mandela

checks one thing: whether a validation is independent, or whether the designer, model, and scorer are only confirming each other.

Workflow

Identify the validation (eval / metric / experiment / holdout / "how we'll know"). Name its components — what plays model, scorer, designer, dataset.
Ask the core question: does external ground-truth enter independently?
Test the validation against all 8 patterns below (some apply only to certain components — a human subject, a scorer); report only the ones that fire, each by name.
Give the independent-ground-truth fix for each hit.

The 8 leakage patterns

Recall, not reason — a memorized answer recited instead of one actually derived; the system already knows the result it is supposedly computing.
Wrong null hypothesis — an ablation that removes a surface label but not the underlying signal the system actually exploits, so the "control" still leaks.
Shared hallucination — two components verifying each other; circularity reported as a number.
Tautology — a scorer grading buckets it drew itself.
Verifier = designer — a private, unreproducible recipe in a holdout's clothes.
Shared-pool bias — train and holdout drawn from one labeler pool, so one bias enters both sides.
Frame injection — a question that hands the subject the hypothesis.
Demand characteristics — measured subjects who know they're being measured.

Rules

Subtlety that bites twice: you can blind the output value and still leak the collection recipe.
Read-only — name the leak and the independence fix; don't rewrite the experiment.

Verification

Turn mandela on this audit:

Run patterns #3–#5 on yourself: are you a scorer grading buckets you drew (Tautology, #4)? is the verifier the designer (#5)? is your verdict a shared hallucination with the design's own claims (#3)?
Could a reader who didn't run the audit reach your verdict from the cited evidence alone — independent ground-truth?
The report names the root, not a laundry list.