  By conditioning on natural language instructions, large language models
(LLMs) have displayed impressive capabilities as general-purpose computers.
However, task performance depends significantly on the quality of the prompt
used to steer the model, and most effective prompts have been handcrafted by
humans. Inspired by classical program synthesis and the human approach to
prompt engineering, we propose Automatic Prompt Engineer (APE) for automatic
instruction generation and selection. In our method, we treat the instruction
as the "program," optimized by searching over a pool of instruction candidates
proposed by an LLM in order to maximize a chosen score function. To evaluate
the quality of the selected instruction, we evaluate the zero-shot performance
of another LLM following the selected instruction. Experiments on 24 NLP tasks
show that our automatically generated instructions outperform the prior LLM
baseline by a large margin and achieve better or comparable performance to the
instructions generated by human annotators on 19/24 tasks. We conduct extensive
qualitative and quantitative analyses to explore the performance of APE. We
show that APE-engineered prompts can be applied to steer models toward
truthfulness and/or informativeness, as well as to improve few-shot learning
performance by simply prepending them to standard in-context learning prompts.
Please check out our webpage at
https://sites.google.com/view/automatic-prompt-engineer.
