Dutiful Replicator

Everything hinges on one restriction: the copy has to target a token you already control, not a creature, not any permanent, but specifically a token. That aperture stops the effect from being a generic doubler and points it at boards where token production is already the plan: a Treasure, a Clue, a Food, a spirit, a 1/1 soldier from some earlier trigger. Whatever engine is running when it lands, this arrives to press the best output a second time. The trigger structure is unusually fiddly for a body this plain. The enters ability offers the payment; paying the sets up a reflexive triggered ability that goes on the stack and lets you pick the target token at that point rather than back on entry. That sequencing matters, because the reflexive ability itself goes on the stack for opponents to respond to before it resolves and creates the token, and because the target is chosen when the ability triggers rather than locked in earlier, keeping it legal even if the board has shifted since it came down. The Assembly-Worker line ties it to a small artifact tribe without asking it to carry that weight; the type is flavor more than function. What the card really represents is the maturing of token-copy from headliner to supporting effect: earlier copy pieces duplicated creatures or permanents wholesale, and this one narrows to tokens precisely because a developed board usually has one worth having twice.