20

Fraud Pre-screening

jev primitiveScore (risk) → bands; frontier only above low (the ladder)
labelsallowreviewinvestigate
dataset21 labeled rows
tracingLangfuse

Pre-screens synthetic card transactions: allow, review, or investigate. Code computes the facts (amount vs the customer's usual, new device, abroad without a travel notice, transactions in the last hour, address changed today). Jev reads the transaction and those facts and gives a risk Score (low, medium, high), and code bands it. The ladder is the readme's cost idea: Jev screens everything, and only the transactions it doesn't call low go to the expensive frontier model. Against them: a rules engine on the same facts ($0), and the frontier model on every transaction. Traced. Measured: accuracy, fraud allowed, good customers stopped, share sent to the frontier, and cost per transaction.

With Jev

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Without Jev

LLM · CODE
Examples

Calls Jev and every baseline for real, traced in Langfuse. Nothing is saved.