A system prompt defines who the agent is and what it does.
This matters more than you think. A well-crafted persona shapes how the agent reasons, which tools it picks, and how it communicates.
Example: “You are a professional contract writer. Your role is to draft, review, and finalize legal documents. You have tools for reading documents, adding notes, and sending emails.”
The persona should include:
- Role (what are you?)
- Responsibilities (what do you do?)
- Constraints (what don’t you do?)
- Tools available (what can you use?).
Clear personas prevent confusion. Without one, the agent might try to do everything. With one, it knows its boundaries.
In multi-agent systems, personas become even more critical. Each agent needs a distinct role. Otherwise they step on each other’s toes.