# Why Prompt Strings Don't Scale in Production

If you've built an AI application, you've probably written prompts like this:

const prompt = `
You are an expert software engineer.

Review the following code.

Return only valid JSON.

Include a severity score.

Do not explain your reasoning.

${code}
`;

It works.

Until it doesn't.

As AI applications grow, prompts stop being "just strings."

They become **business logic**.

Unfortunately, most projects still treat them like text files.

---

The Hidden Problem

At first, your project has one prompt.

Then five.

Then twenty.

Soon you have prompts scattered across your codebase.

src/

├── api/
│   ├── summarize.ts
│   ├── review.ts
│   ├── translate.ts
│
├── agents/
│   ├── planner.ts
│   ├── executor.ts
│
├── prompts/
│   ├── system.ts
│   ├── security.ts
│   ├── rag.ts
│
└── utils/

Every prompt is slightly different.

Nobody knows which instructions are shared.