Design a Langflow prompt chain to automatically generate a concise weekly business report.  The report should include key performance indicators (KPIs) across sales, marketing, and customer service.  The chain should leverage multiple LLMs, potentially including one for data extraction, another for analysis, and a third for report summarization.  The input data should be specified as a structured JSON object containing weekly data for each department (e.g., sales figures, marketing campaign performance metrics, customer support tickets resolved). The output should be a formatted text report (approximately 250 words) structured with clear headings for each department, highlighting key trends and insights.  Assume the data is available in JSON format and accessible via a Langchain Agent. The chain should handle missing data gracefully and include a clear indication if any data is unavailable.  The final report should be suitable for a non-technical audience.  Include a detailed description of each prompt within the chain, specifying the LLM, input, and expected output for each step. Ensure the Langflow chain is designed for efficiency and scalability.