What is an agent instruction?

An agent instruction (also called an agent system prompt) tells a language model how to act in a product: support bot, coding assistant, or research agent. Unlike a one-shot chat prompt, it persists across sessions and tools.

Good instructions use named sections — role, constraints, context, output schema — so teams can update one block without rewriting everything. aiStructEdit is built around this section model with export to Markdown, XML, and Cursor rules.