Below the Harness: Governing a Multi-Model, Multi-Harness World | Docker

This post introduces the concept of a 'runtime layer below the harness' as a fundamental solution to AI agent security and governance challenges. It elaborates on the 'confused deputy' problem in the context of AI agents inheriting user authority and acting probabilistically. The post details three failure modes of per-harness guardrails: agents talking past them, rails moving without user control, and rails not covering the entire fleet. It proposes a unified runtime boundary as the solution, enabling consistent policy enforcement across all agents and harnesses, independent of model or vendor updates, and providing a single audit record. This directly extends the AI Agent Isolation and Secure Execution thread by proposing a new architectural layer for governance.