Microsoft Agent 365 is Microsoft's answer to enterprise agent sprawl: a control plane that registers agents, gives them identities through Entra, applies security and compliance controls via Defender and Purview, and provides observability across an organization's agents — all inside the Microsoft 365 admin surface. It is designed to manage agents at company scale, much like Microsoft 365 manages employees, and it spans agents of every kind, not just coding agents. (Availability is rolling out to Microsoft 365 enterprise customers — check Microsoft for the current status and licensing in your tenant.)
Fleet is narrower and self-hosted. It is a single Go binary that runs Claude Code agents in defined software-development roles, reacts to GitHub label events, and coordinates the dev-review-release chain with its own governance — run-time budgets, agent evaluation, and a risk model. It does not depend on Microsoft 365, Entra, or any cloud suite.