It’s a good question @Sil, with a slightly complicated answer.
Each Skill can have a Stop word defined - which should halt execution of the Skill. Most Skills do have a Stop word defined, however not all do.
The second piece here is slightly more complicated. Mycroft currently does not use echo cancellation
This means that the Stop command sometimes can’t be “heard” by Mycroft when it’s ouputting audio. We currently have a Bounty on this feature:
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