When and Why to Customize Prompt Templates

LangChain provides a robust foundation for building prompt templates using standard methods like `PromptTemplate.from_template()` and `ChatPromptTemplate`. For a significant number of use cases, these built-in classes and their supported templating engines (like f-string or Jinja2) are entirely sufficient. They offer a straightforward way to define static structures and inject dynamic variables, covering common tasks from simple Q&A to complex conversation flows.

However, as applications grow in complexity and requirements become more specific, you may encounter scenarios where the standard functionalities present limitations. The default templates are designed for broad applicability, but they cannot anticipate every unique data structure, validation rule, or rendering requirement your application might have.