PromptAgent: Strategic Planning with Language Models Enables Expert-level Prompt Optimization

PromptAgent: Strategic Planning with Language Models Enables Expert-level Prompt Optimization
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Original Paper
Highly effective, task-specific prompts are often heavily engineered by experts to integrate detailed instructions and domain insights based on a deep understanding of both instincts of large language models (LLMs) and the intricacies of the target task. However, automating the generation of such expert-level prompts remains elusive. Existing prompt optimization methods tend to overlook the depth of domain knowledge and struggle to efficiently explore the vast space of expert-level prompts. Addressing this, we present PromptAgent, an optimization method that autonomously crafts prompts equivalent in quality to those handcrafted by experts. At its core, PromptAgent views prompt optimization as a strategic planning problem and employs a principled planning algorithm, rooted in Monte Carlo tree search, to strategically navigate the expert-level prompt space. Inspired by human-like trial-and-error exploration, PromptAgent induces precise expert-level insights and in-depth instructions by reflecting on model errors and generating constructive error feedback. Such a novel framework allows the agent to iteratively examine intermediate prompts (states), refine them based on error feedbacks (actions), simulate future rewards, and search for high-reward paths leading to expert prompts. We apply PromptAgent to 12 tasks spanning three practical domains: BIG-Bench Hard (BBH), as well as domain-specific and general NLP tasks, showing it significantly outperforms strong Chain-of-Thought and recent prompt optimization baselines. Extensive analyses emphasize its capability to craft expert-level, detailed, and domain-insightful prompts with great efficiency and generalizability.

Summary Notes

Simplifying LLM Prompt Optimization with PromptAgent

In the dynamic world of artificial intelligence (AI), efficiently working with large language models (LLMs) is crucial for AI engineers.
Crafting effective prompts tailored to specific tasks is at the heart of this work. The introduction of PromptAgent has made a significant impact by making the prompt optimization process more strategic and efficient.

The Challenge of Prompt Engineering

Originally, prompt engineering was more of an art form, requiring manual effort and a deep understanding of the model and task at hand.
With the introduction of automated optimization methods, the process became more systematic, yet it still faced limitations.
These methods typically relied on a trial-and-error approach without a strategic framework, making the optimization process lengthy and less effective.

Introducing a Strategic Solution: PromptAgent

PromptAgent revolutionizes prompt optimization by treating it as a strategic planning problem. It uses Monte Carlo Tree Search (MCTS), a strategy successful in games like Go, to explore and refine prompts methodically.
This approach allows for systematic improvement based on feedback, making the search for optimal prompts more structured and efficient.

How Does PromptAgent Work?

  • Starting Point: Begins with an initial human-written prompt and training samples.
  • Exploration: Uses MCTS to systematically explore different prompt variations.
  • Refinement: Each iteration refines the prompt based on feedback, aiming for the most effective interaction with the LLM.

Demonstrated Success

PromptAgent's effectiveness has been proven across various tasks in three domains: BIG-Bench Hard tasks, domain-specific NLP tasks, and general NLP tasks. It consistently outperformed both human-crafted prompts and other automated tools, showing a notable ability to incorporate domain-specific knowledge into its prompts.

Looking Forward

PromptAgent represents a significant advancement in LLM prompt engineering, combining strategic planning with the intricate needs of prompt optimization.
Its success not only highlights the potential of strategic planning in this area but also opens up new research and development opportunities.
As the AI field continues to evolve, tools like PromptAgent will play a key role in enhancing the utility and effectiveness of LLMs.


PromptAgent marks a major step forward in LLM prompt engineering, offering a strategic and structured approach to overcoming the challenges of prompt optimization. Its proven effectiveness across a wide range of tasks positions it as a pivotal tool for AI engineers, particularly in enterprise settings where efficiency and precision are crucial.
As AI technology progresses, the strategies underpinning PromptAgent are set to influence future advancements in LLM interactions and beyond, making it a beacon of innovation in the quest for expert-level prompt optimization.

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