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Prompt Decomposition: Definition and Examples

Technique of breaking down a complex task into several simpler and more targeted sub-prompts, in order to obtain more precise and reliable responses from a language model.

Full definition

Prompt Decomposition is a fundamental strategy in prompt engineering that involves breaking down a complex query into a series of smaller, more manageable sub-tasks. Rather than asking a language model to solve an entire problem at once, you guide it step by step through each component of the problem.

This approach is directly inspired by the algorithmic decomposition principle in computer science, where a complex problem is solved by dividing it into independent sub-problems. In prompt engineering, this translates into sending several sequential prompts, each addressing a specific aspect of the overall task. The result of each step can serve as input for the next, creating a structured reasoning chain.

The main benefit of decomposition lies in reducing the cognitive load imposed on the model. When a prompt is too dense or multi-dimensional, the model may lose track, omit important elements, or produce superficial responses. By isolating each sub-task, you maximize the quality and depth of each intermediate response.

Prompt Decomposition is particularly effective for analysis tasks, long-form writing, multi-step problem solving, and code generation. It is one of the pillars of advanced prompt engineering workflows and naturally combines with other techniques like Chain-of-Thought or prompt chaining.

Etymology

The term combines 'prompt' (instruction given to an AI model) and 'decomposition' (from Latin decomponere, 'to separate into elements'). It borrows from computer science vocabulary where functional decomposition refers to dividing a system into simpler modules. Its use in prompt engineering became widespread from 2023 onwards with the increasing complexity of tasks assigned to LLMs.

Concrete examples

Writing a complete blog article

Step 1: "List the 5 main arguments in favor of telecommuting." Step 2: "For each argument, write a 100-word paragraph with a concrete example." Step 3: "Write an engaging introduction and a conclusion that synthesizes these arguments."

Analyzing a customer dataset

Step 1: "Identify the 3 most represented customer segments in this data." Step 2: "For each segment, describe the typical purchasing behavior." Step 3: "Propose a marketing strategy tailored to each segment."

Developing a software feature

Step 1: "Define the interface and required data types." Step 2: "Implement the main business logic." Step 3: "Add error handling and edge cases." Step 4: "Generate corresponding unit tests."

Practical usage

To apply Prompt Decomposition, start by identifying the logical steps of your task, then formulate a separate prompt for each. Pass the result of each step as context for the next prompt. Test each sub-prompt individually before chaining them, which facilitates debugging and optimization of your complete workflow.

Related concepts

Chain-of-Thought PromptingPrompt ChainingTask DecompositionFew-Shot Prompting

FAQ

What is the difference between Prompt Decomposition and Chain-of-Thought?
Chain-of-Thought asks the model to reason step by step within a single prompt, while Prompt Decomposition splits the task into several separate prompts. Decomposition offers finer control because you can check and adjust each intermediate result before moving to the next step.
How many sub-prompts should be created for a given task?
There is no universal rule, but a good indicator is to create one sub-prompt per distinct objective. If a prompt requires two different skills (e.g., analyze then write), it is usually better to split it. In practice, 3 to 7 steps cover most common use cases.
Does Prompt Decomposition work with all language models?
Yes, this technique is universal and works with all LLMs (GPT, Claude, Mistral, Llama, etc.). It is even particularly beneficial with smaller models that struggle more with complex instructions in a single pass. The more limited the model, the more decomposition improves the quality of results.

See also

How to use this prompt

  1. Copy the prompt with the button above.
  2. Paste it into ChatGPT, Claude or your favorite AI assistant.
  3. Replace the bracketed variables with your details, then refine the result.

About Prompt Guide

Prompt Guide is a free library of 2500+ ready-to-use prompts for ChatGPT, Claude and other AIs, with guides to learn prompting and tools to build and optimize your own prompts.

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