MedToolFault and MedGuard: evaluating and improving clinical agent reliability
arXiv:2611.09942v1 Announce Type: new Abstract: Clinical agents must retrieve patient-specific evidence and correctly update records despite unreliable tool responses. We introduce MedToolFault, a fault-injection benchmark linking six tool-failure classes to answer correctness, required state changes and forbidden mutations in public clinical-agent tasks. We also introduce MedGuard, a tool-layer method that verifies read evidence and attributes ambiguous writes through public interfaces. Across 127,861 formal episode evaluations, we assess fault recovery, mechanism controls, task expansion, co