The 'add' tool has a trivial implementation with minimal documentation. The tool definition is visible in packages/sdk/examples/math.ts, but critical quality dimensions are severely lacking. The input schema uses a bare string format ('a': 'number', 'b': 'number') rather than proper JSON Schema with type objects and descriptions. The tool description ('Adds two numbers together') is only 28 characters, below the 34-char p10 baseline. No output schema is documented in the ToolSpec type or the tool registration. The example does not demonstrate real-world complexity or follow production patterns for error handling, validation, or composability.

• Refactor ToolSpec to use proper JSON Schema: change 'input: Record<string, string>' to 'input: { type: "object", properties: { ... }, required: [...] }' with full type and description for each property.
• Expand tool description to 50-150 characters explaining WHAT the tool does, WHEN to use it (e.g., 'Use to compute the sum of two numbers'), and WHAT it returns (e.g., 'Returns an object with a sum field').
• Document the output schema explicitly. Add to ToolSpec: 'output: { type: "object", properties: { result: { type: "number", description: "The sum of a and b" } } }'.
• Add parameter descriptions: 'a: number, the first operand (can be positive, negative, or zero)' and 'b: number, the second operand (can be positive, negative, or zero)'.
• Implement input validation in the tool handler: check that a and b are numbers, provide actionable error messages (e.g., 'Invalid input: a must be a number, got string').
• Add error handling that categorizes failures as retryable vs fatal. For example, if a is undefined, return a clear error: 'Missing parameter a. Pass a number for the first operand.'
• Consider renaming to 'add_numbers' (verb_noun pattern) for clarity, though 'add' is acceptable for mathematical operators.