The MCP SDK Go repository provides a framework for building MCP servers, but evaluation focuses on the single example tool 'calculate' defined in examples/client/cli-use/main.go. This tool has critical definition quality issues: (1) The input schema declares 'second' as type 'array' with description 'array of numbers', but the tool description says it 'calculates the sum of two numbers', a scalar operation, not an array operation. This is a fundamental schema-description mismatch. (2) The tool name 'calculate' is a generic verb that violates naming conventions, it should be 'sum_numbers' or 'add_numbers' to indicate the specific action. (3) Parameter 'first' is described minimally ('This is the first parameter') without explaining what values are valid, what range is accepted, or how it relates to the operation. (4) No output schema is documented anywhere in the source code. (5) No error handling guidance is visible. The tool appears to be a framework demo rather than a production-quality definition. The schema.go file shows the framework SUPPORTS annotations (readOnlyHint, destructiveHint, idempotentHint) and structured schemas, but the example tool does not use them effectively.

• Rename 'calculate' to 'sum_numbers' or 'add_numbers' to follow verb_noun naming convention and clearly indicate the operation performed.
• Fix the schema-description mismatch: either change the tool to accept an array and actually sum all elements, or fix the schema to match the description of summing two scalar numbers.
• Expand parameter descriptions. For 'first': describe it as 'A numeric value (integer or decimal) to be summed with the second number. Must be a valid number.' For 'second' (if scalar): similar description with numeric constraints.
• Document the output schema explicitly: 'Returns an object with fields: {sum: number} where sum is the arithmetic result of first + second (or first + sum of array elements).'
• Add error handling guidance: 'If either parameter is not a valid number, returns an error: Invalid input: <field> must be a number, not <received_type>. Please provide numeric values.'
• Populate tool annotations: set readOnlyHint=true since the calculate tool has no state-modifying side effects.
• Provide a realistic tool example if this is meant as a demo. Alternatively, document that this is a framework-level example and direct users to a more complete production example.