kabu-mcp has 7 tools with basic schemas and descriptions, but significant gaps limit production readiness. All tools have descriptions (10-80 chars, mostly short), and input schemas are present with Zod validation. However, descriptions lack depth, most are under 50 chars and omit WHEN to use each tool or what it returns. Parameter descriptions are minimal (e.g., 'Ticker or Japanese name' for symbol). No output schemas are documented, forcing LLMs to infer response structure. Error handling returns raw error messages without recovery guidance. The 'gate()' pattern for pro features is clever but not transparent in tool descriptions, users won't know a tool is locked until invoked. Tool composition is reasonable (each does one thing), but missing pagination, result limits, and field-level documentation.

• Add output schema documentation for each tool. Example for get_quote: 'Returns {symbol, name, currency, exchange, price, change, changePercent, dayHigh, dayLow, volume, marketState, timestamp}.'
• Expand tool descriptions to 80-150 chars. Include WHEN to use and what it returns. Example: 'Get real-time stock quote for Japan (7203.T) or US (AAPL) symbols. Returns price, change, volume, and market state. Use before technical_analysis() to verify symbol exists.'
• Add explicit license requirement to pro tool descriptions: 'Requires KABU_MCP_LICENSE_KEY environment variable (kabu_pro_* prefix). Free tier unavailable.'
• Enhance error messages with recovery hints. Replace 'Error: No data' with 'Symbol not found. Try search_stocks("Toyota") to find the correct ticker, then retry.'
• Document parameter constraints in descriptions. Example for range: 'Time range (1d=1 day, 1mo=1 month, 1y=1 year, 5y=5 years). Default 1mo.'
• Add per-tool result limits to descriptions. Example: 'Returns up to 15 matching stocks. Use search_stocks() to narrow results.'
• Return structured error objects with error_code and recovery_suggestion fields instead of plain text.