Claude Opus 4.1 Prompt for Structured Extraction

Design a system prompt for Claude Opus 4.1 to extract specific entities (e.g., 'CEO_Compensation_Total', 'Board_Diversity_Metrics', 'Shareholder_Proposal_Summary') from a provided text chunk of a proxy statement. The output should be a JSON object. Ensure the prompt explicitly instructs the LLM on handling missing data and ambiguous phrases, and include examples.