r/AI_Agents: Developer Who Let One Agent Handle Intake, Lookup, Updates, and Reply Documents 4 Distinct Failure Modes — Running AMA on Guardrails and Handoffs

A production agent builder documents four distinct failure modes from routing intake, lookup, system updates, and final reply through a single agent: bad tool calls, stuck retry loops, silent wrong-branch execution, and cascading state corruption that left no log trace. The post is running as a live AMA on guardrails and handoff design, drawing practitioners who recognize the same 'seemed efficient on paper' architectural trap. Comments are converging on the observation that agent failure surface grows super-linearly with scope, making task decomposition a reliability requirement rather than a style choice.