{
    "action": "tool_call",
    "reasoning": "I need to understand what numeric metrics exist across all tables to identify the most important one. The llm_calls table has several measures (input_tokens, output_tokens, cost_usd, latency_ms), but I should check what other key metrics exist in other major tables like job_logs, analysis_runs, batches, etc. Let me query the column metadata to find all measure-type columns across the dataset.",
    "tool": "query_sql",
    "sql": "SELECT table_name, column_name, phys_type, null_count, distinct_count FROM analytics.column_overview WHERE aggregation_role = 'measure' AND phys_type IN ('BIGINT', 'DOUBLE', 'DECIMAL', 'INTEGER') ORDER BY distinct_count DESC LIMIT 50",
    "purpose": "Find all measure-type columns across the dataset to identify the most important numeric metric"
}