DictionaryPrompt Engineering
System Prompt
Standing instructions given to the AI before the conversation starts, like a job description it follows throughout.
Definition
Instructions provided at the beginning of a conversation to set the model’s behavior, personality, and constraints. System prompts are ideal candidates for caching since they remain constant across requests.
Example
The system prompt You are a senior TypeScript reviewer. Flag security issues first. applies to every turn and is a good cache candidate.
Appears in
- Don't Break the Cache: An Evaluation of Prompt Caching for Long-Horizon Agentic TasksarXiv
- Prompt caching with the Claude APIClaude Cookbook
- Session Memory CompactionClaude Cookbook
- Context Engineering for AI Agents: Memory vs. Compaction vs. Tool ClearingClaude Cookbook
- Cost Optimization on the Claude APIClaude Cookbook