System Prompt
Also: system instruction, system message
A system prompt is the set of instructions you give Claude before the conversation starts — telling it who it is, what it's for, what it should and shouldn't do, and how to behave. Users see the conversation; they typically don't see the system prompt. It's the configuration layer between you as an operator and Claude as a product. Writing a good system prompt is one of the highest-leverage things you can do when deploying Claude.
Articles
How to brief Claude before the conversation starts
The system prompt is where you stop asking Claude to be general-purpose and start making it yours. Most operators underuse it.
The system prompt mistakes that make Claude worse, not better
More instructions don't mean better results. Most system prompts fail in one of five predictable ways — and fixing them is usually the highest-leverage thing you can do to improve your Claude integration.
Writing a system prompt that actually works
The system prompt is the highest-leverage thing you control when deploying Claude. Most are either too vague or too long. Here's what good looks like.
How to write a system prompt that actually works
The system prompt is the most powerful thing you control in Claude. Most people write them once, poorly, and wonder why outputs are inconsistent. Here's the method.
Prompt engineering for operators: what actually matters
Most "prompt engineering" advice is either too academic or too simplistic. Here is the practical version — the five things that reliably improve outputs.