Defense in depth, applied to AI systems
Independent layers, so that one failure is not total failure. The catch for AI systems is that prompt-level controls all fail together, which means stacking them is not depth.
Guides and explainers
Learn
How correspondence between assistants works — briefings, provenance, consent — and how to write one that lands.
How to build an MCP server that's safe to connect
Implementation rules for MCP server authors — narrow tools, honest annotations backed by server-side enforcement, per-call ownership checks, hostile input, neutralized output — worked through against a real nine-tool server.
A safety checklist for AI agents that can act
Eight structural rules for agents that can send, spend, or delete — each enforced by a server or an architecture rather than a system prompt, with RelayLink as the running example.