Original title: Instruction Duplication as an Inference-Time Control Primitive
Victor Lavrenko · September 2026
Language models often fail to follow multi-step rules, especially when other systems need to inspect or repair their work. To fix this, researchers tested a simple trick called instruction duplication. Instead of retraining the model or changing how it picks words, they simply repeated the procedural instruction twice during testing. This gives the model a second chance to catch the rule. Repeating the instruction raised success on an eight-test diagnostic from 90.22% to 93.17%, removing 30.2% of the errors left after a single copy. Vocabulary recall also improved from 73.44% to 74.81%. Final-answer accuracy stayed exactly 60.21%, but jumping to conclusions early grew from 1.52% to 2.30%. The boost matters most when another program uses the model's intermediate steps. In one repair task, success jumped from 84.2% to 97.1%. Repeating an instruction is an easy control that helps downstream tools act on generated paths.
Imagine following a recipe with many steps in a busy kitchen. It's easy to overlook a critical instruction because you're distracted or in a hurry. To prevent this, you could write that key step twice on the card, so it catches your attention when you glance at it. In this paper, repeating the procedural instruction for an AI acts like that double-written note, making the AI more likely to complete all steps correctly without changing how it learns.
This matters for developers and users of AI systems that need precise step-by-step execution, like in medical diagnostics or automated repairs. It reduces errors when outputs must be checked or fixed later, making control simpler.
The abstract notes that a blinded audit did not confirm the effect strongly, with only 10 out of 30 directional confirmations, and the method increased premature commitment slightly. Its benefits are context-dependent, emerging mainly with specific downstream systems like Answer Engineering.
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Instruction Duplication as an Inference-Time Control Primitive — Victor Lavrenko
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.