A 403 I fully expected to be a 200 — in a lab, not a bug — turned into the design rule for a whole project: let an AI answer questions about thousands of endpoints without ever giving it a way to change one.
Everything else on my site — the ten read-only collectors, the Power BI reports, the AI agent that answers questions about a fleet without touching it — points back to one moment in a lab tenant: a 403 I fully expected to be a 200. Not a bug. The system working exactly as designed. That 403 is the reason the whole project is built the way it is, and this is the artifact that came out of it.
The proof, in one screen:
PS> . .\read-only-gate.ps1
Zero-Access read-only gate — identity: aa-collectors [<guid>]
[read ] DeviceManagementManagedDevices.Read.All
[read ] Directory.Read.All
[WRITE] DeviceManagementManagedDevices.ReadWrite.All
READ-ONLY GATE FAILED — write-capable Graph roles granted:
DeviceManagementManagedDevices.ReadWrite.All. Refusing to