How Many Credentials Should Your AI Agent Have? Zero. — Jim Clark, Docker

This post contributes to agent harness engineering by detailing a strategy for AI safety through sandboxing and credential management. It proposes using MCP gateways as a central control point for agent sandboxes, defining the sandbox by the tools and context it has access to, rather than the harness itself. The core principle is that the right number of credentials for an agent sandbox is zero, with tools and permissions granted progressively via Cross App Access (XAA) with Okta, aligned with the specific intent of the task. Examples include a newsroom split into researcher, fact-checker, and publisher sandboxes, and a coding agent that only receives signing keys when committing code.