Lexifina reconstructs 365 US Code amendments across nine titles with 361 exact matches to official release points

The project converts statutory release points into a dated, attributable record by executing public law amendments in enactment order. Each change receives the originating Act, effective date, and text delta. Four discrepancies receive explicit labels rather than forced reconciliation. This produces queryable snapshots where a selected date returns the governing text with prior wording highlighted and color-coded by source statute.

Data from the Technical University of Munich study showed models answering post-cutoff German statute questions at 24 percent accuracy unaided and 87 percent when supplied current text. A follow-on experiment found only half of single amendments and one-fifth of chained amendments reproduced exactly, with experts identifying legally material errors in the remainder. Lexifina's 99 percent exact reproduction rate on US titles supplies the verifiable lineage those models currently lack.

Operationally the system lets counsel retrieve the rule in force on any filing date, isolates retroactive provisions, and exposes effective-date notes without manual cross-reference. It also supplies training data that treats temporal validity as a hard constraint rather than a retrieval suggestion. Extension to remaining non-positive-law titles and live integration with the Office of the Law Revision Counsel release schedule are the immediate next increments.