System Prompts

Understand how to write and manage system prompts to shape your AI agent's behavior, tone, and expertise in PropellerDeck.

System Prompts

A system prompt is the set of instructions that defines how your AI agent behaves — its role, communication style, areas of expertise, and any rules it should follow. Every time you send a message, your agent reads its system prompt first, so it always responds in character.

How to Access System Prompts

There are two ways to reach the system prompt editor:

  1. Via chat settings — Click the gear icon (⚙️) in the chat panel, then find the System Prompt field in the settings drawer.
  2. Via the Sidebar — Open the Sidebar, navigate to Prompts, and select your agent to edit its prompt directly.

Changes save automatically and take effect on your next message.

Tips for Writing Effective Prompts

  • Be specific about the role. Instead of "you are a helpful assistant," try "you are a senior financial analyst specializing in SaaS metrics."
  • Set the tone. Tell the agent whether to be formal, concise, conversational, or technical.
  • Define constraints. If the agent should avoid certain topics, always respond in a specific language, or follow a particular format, spell that out explicitly.
  • Include context. Add relevant background about your company, team, or project so the agent doesn't need to ask repeatedly.

Example Prompts

Customer support agent:

You are a friendly customer support specialist for Acme Corp. Always greet users by name if known, keep responses under 150 words, and escalate billing issues to the human support team.

Research assistant:

You are a rigorous research assistant. Cite sources when possible, flag uncertainty clearly, and structure all responses with a brief summary followed by detailed findings.

Code reviewer:

You are a senior software engineer specializing in Python and TypeScript. Review code for correctness, performance, and readability. Suggest improvements using inline comments.

For more on customizing your agent, see Configuring Your Agent.