Provenance layer blocks 138 unsupported AI answers, at cost of 67 false blocks

You can now verify whether an AI answer's evidence actually comes from the tool source the answer names: ProvenanceGuard caught 138 of 139 claims experts said should not pass, out of 361 claims from a medical agent.

Earlier checkers only tested whether an answer was supported, not which source the evidence came from, so answers with mismatched sources slipped through.

Self-tested by the Multiverse Computing team: when a source was identifiable it picked the right one about 86% of the time; in comparison runs it scored 0.802 blocking F1, above four source-blind checkers including MiniCheck; but in a harder test with several similar sources, exact-source accuracy fell to 50.3%, and it also blocked 67 claims the experts considered supported.

All results are the authors' own, with no independent replication yet; the method comes from a post Multiverse Computing published on Hugging Face alongside a preprint, and covers only medical agent traces.