`att` can be an empty array

With the latest changes we are using `type Tuple = [T, ...T[]]` for Capabilities which forces att to have at least one element but att can be an empty array.

What should we do here ?

Locate the Capabilities definition and the Tuple type referenced in the issue, then inspect the existing type checks or tests for att. Confirm how an empty att array is represented and determine the intended type behavior; done means the type definition and coverage accept the valid empty case without weakening unrelated constraints.

Written by the indexing model from the issue text.