Microsoft's Guardian Agents, and the agentic future of ad verification

Microsoft is building "Guardian Agents" to monitor AI systems running inside a business network, with discovery extended to 60 local agents including Claude Code, OpenAI Codex and GitHub Copilot. Satya Nadella framed the principle: "The most trustworthy agentic system will not be the one with the model we trust most... It will be the one designed that enables us to trust the model least." MediaPost notes the framework applies directly to ad tech, where anonymous, non-verified "shadow" agents clicking pay-per-click ads already cost the industry billions.