Claude API · Shaping requests
Add a system prompt
Set Claude's role and rules with the top-level system parameter.
response = client.messages.create(
model="claude-opus-5-5",
max_tokens=16000,
system="You are a helpful coding assistant. Always provide examples in Python.",
messages=[{"role": "user", "content": "How do I read a JSON file?"}],
)
Official Claude API documentation