MemSyco-Bench: Retrieved Memories Make Agents Sycophantic, and Nobody Was Measuring It

arXiv / HuggingFace Daily Papers·medium signal

MemSyco-Bench (arXiv 2607.01071, submitted July 1) argues existing memory benchmarks only test whether memories are correctly stored, retrieved, and updated — never whether the retrieved memory should have influenced the decision at all. The benchmark's five tasks test whether agents can reject memory as factual evidence, respect its applicable scope, resolve memory-versus-objective-evidence conflicts, track updates, and still use valid memory for personalization. The failure mode it names is sharp: agents over-align with the user because a stored memory says so, at the cost of factual accuracy. Anyone shipping a persistent-memory agent should read this before trusting their retrieval layer.