3Accessing Claude with the API
System prompts exercise
2 min read303 words
Time: 10–15 minutes
Write a system prompt for a specific professional role and see for yourself how dramatically it changes Claude's output on the same question.
Step 1—Call Claude Without a System Prompt
Pick a question you would realistically ask at work. Two good candidates:
- "A user is getting a 500 error when they submit the checkout form. What should I ask them?" (customer support)
- "Review this function for bugs and style issues: ..." (code review — paste 10–20 lines of real code)
Call chat(messages) with no system argument and save Claude's raw, persona-less response. Notice how generic and tonally neutral it is.
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You can now design system prompts that reliably shape Claude's behaviour for any role or use case.