MCP Security in Action: Decision-Lineage Observability

Traditional observability tells you what broke. Agentic observability must tell you why the agent decided to break it - before the decision cascades into production. After sharing the risk-classification framework (Part 1) and the Cloud Security Alliance's Six Pillars of MCP Security (Part 2), the obvious next question was: how do we actually observe and audit why an agent made a particular change? This post covers the decision-lineage architecture I shipped in a regulated cloud-native environment over the past two weeks, and the results.