ARC0004: Command has no instance handle

What

@command() requires an instance handle() method, either on the command or inherited from a base class. Rule: arc-core/arc0004.

Why

A missing or static handler cannot be invoked through the command pipeline. TypeScript private and protected only restrict compile-time access: the runtime can invoke those handlers, so the rule does not reject them.

Bad

@command()
export class Register { static handle() {} }

Good

@command()
export class Register { handle() {} }