Your LLM prompts are interfaces. Start treating them like it.

If you've ever debugged a production LLM system by "just rephrasing the prompt," this post is for you. The problem isn't the model. It's the instruction. Most LLM instructions are written the way people write notes to themselves, informally, with shared context assumed, maintained by whoever wrote them. This works for one-off experiments. It fails in systems where instructions are authored once, executed thousands of times, and maintained by teams who weren't there when the original decisions...