Financial Modeling Prep MCP exhibits solid foundational quality with consistent naming, all tools having schemas and descriptions. However, it suffers from several systematic issues: (1) output schemas are not documented, no visibility into what fields/structures each tool returns, forcing LLMs to guess; (2) parameter descriptions are frequently generic or minimal, lacking actionable constraints; (3) no error handling guidance, tools fail silently without recovery hints; (4) no input validation examples; (5) descriptions are moderately detailed (avg ~80 chars) but lack WHEN-to-use context; (6) no pagination guidance for high-volume data (news, market data, earnings calendar). The tool definitions themselves are well-formed JSON Schema with types and enums, and naming is consistently verb-noun (get_*, search_*), which are major positives. This server would function but lacks production-grade refinement.

• Document output schemas for every tool. Add an 'Output' section to each tool description listing key fields returned. Example: 'Returns: {symbol, price (float), change (float), changePercent (float), volume (int), marketCap (string)}'.
• Add error handling guidance. Specify common failure modes and recovery steps. Example: 'If symbol not found, try search_symbol() first. If no data available for period, try a shorter date range.'
• Enhance parameter constraints. For 'limit' params, add bounds: 'limit (1-100, default 10)'. For date params, add format and range: 'from (YYYY-MM-DD, defaults to 30 days ago)'.
• Add pagination guidance to list-returning tools. Example: 'Returns up to 50 results. Use limit parameter to control page size. No offset/cursor pagination available; results are always latest N items.'
• Expand 'When to use' context in tool descriptions. Example for get_analyst_estimates: 'Use this when you need forward-looking revenue/EPS forecasts. Use get_key_metrics for historical ratios like P/E and ROE.'
• Validate date formats in tool implementation. Return clear errors: 'Invalid date format. Expected YYYY-MM-DD, got 2024-13-45.'
• Document any API rate limits or data freshness expectations. Example: 'Stock quotes update during market hours. Economic indicators publish monthly, typically 2-3 days after month-end.'
• Add HTTP status code comments to the fetchFMP helper indicating which codes are retryable (429, 503) vs user-fixable (400, 404).
• Consider capping high-volume result sets. Example: get_earnings_calendar and get_stock_news could default to limit=20 (current code shows no cap), preventing accidental 1000+ item responses.