Do LLMs really weight instructions by position?

Yes. Models show measurable primacy and recency effects — instructions at the very start and very end of a prompt are followed more reliably than those buried in the middle, an effect often called 'lost in the middle'. Explicit priority labels reinforce the ordering further.

What is the 'lost in the middle' problem?

It is the documented tendency of LLMs to attend less to content placed in the middle of a long context, even when it is critical. The fix is to position your most important instructions near the beginning or end and to mark their priority explicitly.

Why add explicit priority labels?

Position helps, but a clear label like 'HIGHEST PRIORITY' or 'if instructions conflict, follow rule 1 first' gives the model an unambiguous tie-breaker. Combining position and labels is more robust than either alone.

Does this guarantee the model obeys?

No. It stacks the odds in your favor using known position and labeling effects, but model behavior is probabilistic. Test the output and iterate.

Prompt Instruction Priority Ranker

Prompt instruction priority ranker

When a prompt carries several rules, they compete for the model’s attention — and the model does not weigh them equally. Instructions near the start (primacy) and end (recency) of the prompt are followed more reliably than those stranded in the middle, a pattern often called “lost in the middle.” This tool takes your raw instructions and a priority order, then arranges them to exploit those effects and tags each with an explicit weight.

How it works

You enter your instructions and rank them top to bottom by importance. The ranker then builds a position-optimized block: the highest-priority rule is placed first, the second-highest is placed last, and the remaining rules fill the middle in descending order — so your two most important instructions occupy the two strongest positions. Each rule is prefixed with an explicit priority label, and a tie-breaker line tells the model which rule wins if two instructions conflict. The result is a drop-in instruction block for any system or user prompt.

Tips and notes

Put hard constraints at rank 1. Safety rules, format requirements, and “never do X” lines belong at the top so they land in the primacy slot.
Reserve rank 2 for the second non-negotiable. It gets the recency slot at the end, the next-strongest position.
Keep each instruction atomic. One rule per line ranks cleanly; compound instructions blur the priority signal.
Re-test after reordering. Position effects are real but probabilistic — verify the model now honors the rule that was previously ignored.