Tools / Microsoft Threat Modeling Tool (TMT) Interview questions
Why should you re-run threat generation after editing an existing data flow?
TMT computes threats at the moment you click Generate, based on each element's state at that exact time - it doesn't retroactively recompute anything when you later change a flow's direction, its connected endpoints, or whether it now crosses a trust boundary.
Skip the re-generation and you end up with two problems at once: stale threat entries that no longer reflect what the flow actually does today (possibly already marked Mitigated against an outdated description), and newly relevant threats from the edit that simply never get created until you regenerate. Both failure modes look identical to "the model is fine" until someone checks against the current diagram.
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