Two tools are registered as resources (not traditional MCP tools). Both have minimal parameter descriptions and lack output schema documentation. Input schemas are inferred from function signatures rather than explicitly registered with JSON Schema. Descriptions are present but generic. No error handling guidance, no parameter constraints, no output field documentation. This server treats financial metrics as read-only resources exposed via URI templates, which is a reasonable pattern choice, but the implementation lacks the specificity required for production agent use.

• Convert resource definitions to explicit tool definitions with complete JSON Schema input and output. Register via FastMCP's @mcp.tool decorator if available, ensuring schema includes type, description, and enum constraints for the ticker parameter.
• Document output schemas for both tools. Example: 'Returns object with fields: stock (string), earningsYield (float or null). If null, the ticker was not found or the metric is unavailable.'
• Enhance parameter description: 'ticker (string): Stock ticker symbol in uppercase, 1-5 characters (e.g., MSFT, AAPL, BRK.B). Must be a valid public company listing.'
• Add error handling guidance in tool descriptions: 'On failure, returns error with HTTP status code. Common issues: (1) ticker not found, try a different symbol; (2) service unavailable, retry in 30 seconds; (3) invalid format, ticker must be uppercase alphanumeric.'
• Add parameter constraints: if using JSON Schema, define ticker pattern as '^[A-Z]{1,5}(\.)?[A-Z]?$' to enforce format.
• Document the difference between the two tools in their descriptions. 'Earnings Yield measures profitability relative to value; Return On Tangible Capital measures capital efficiency. Use both to cross-validate investment thesis.'
• Implement server-side validation: reject ticker parameter if length > 5, if contains lowercase, or if blank. Return 400 with: 'Invalid ticker format. Expected uppercase 1-5 characters, got "<value>".'
• Return structured responses with ISO format numbers (not JSON serialization of floats) and a status field: {status: 'success', stock: 'MSFT', earningsYield: 0.082, timestamp: '2025-01-15T10:30:00Z'} or {status: 'error', code: 'NOT_FOUND', message: '...'}