# Custom Optimizer Prompts

> Learn how to override and customize the internal prompt templates used by Opik optimizers to add domain constraints, safety requirements, or custom formatting.

The Opik Optimizer uses a **PromptLibrary** system that lets you customize the internal prompts used by each optimizer. This is useful when you need to:

* Add domain-specific constraints (legal, medical, coding standards)
* Inject safety or compliance requirements
* Adjust output formatting or style
* Experiment with different reasoning approaches

## Quick Start

Every optimizer accepts a `prompt_overrides` parameter:

```python
from opik_optimizer import MetaPromptOptimizer