# Promptbreeder

> Promptbreeder is an evolutionary prompt-optimization method in which a population of task prompts is mutated and selected by fitness on training examples, while the mutation prompts that generate the changes are themselves evolved.

- Identifier: PTL-0153
- Category: Prompt Optimization
- Canonical URL: https://protologue.com/t/promptbreeder/
- Introduced: 2023

## Description

Because the instructions for how to mutate prompts also improve over time, the method is described as self-referential. It discovered domain-specific prompts that outperformed hand-written chain-of-thought prompts on arithmetic and commonsense benchmarks, at the cost of many model calls.

## Broader terms

- [Prompt Optimization](https://protologue.com/t/prompt-optimization/)

## Related terms

- [EvoPrompt](https://protologue.com/t/evoprompt/)
- [Optimization by Prompting](https://protologue.com/t/opro/)
- [Automatic Prompt Engineer](https://protologue.com/t/automatic-prompt-engineer/)

## Sources

- Fernando et al. (2023). Promptbreeder: Self-Referential Self-Improvement Via Prompt Evolution. https://arxiv.org/abs/2309.16797

## Cite this entry

Protologue. (2026). Promptbreeder. In Protologue: A Taxonomy of Prompting and LLM Techniques (v1.4.0, PTL-0153). https://protologue.com/t/promptbreeder/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)