The Three-Layer Agentic Architecture Most Teams Build Wrong

A widely-cited LangChain post on agentic architecture gives this advice: outsource your agentic infrastructure, own your cognitive architecture. It's good advice. It's also incomplete - and the gap it leaves is where most production governance failures originate. The post describes two layers: infrastructure (execution, queues, persistence - outsource it) and cognitive architecture (how your agent reasons, what tools it has, how it plans - own it). What it doesn't describe is the third layer - because the governance plane wasn't a serious engineering problem when that piece was written.