Five tools with basic descriptions and schemas, but significant gaps in parameter documentation and error handling. Tool names follow verb_noun convention (add, subtract, multiply, divide, current_datetime), which is good. However, parameter descriptions are minimal (e.g., 'First number', 'Second number' for add/subtract/multiply), and critical error cases like division by zero are handled in code but not documented in the tool description. The current_datetime tool accepts a ToolRuntime parameter with embedded context, which is non-standard for LLM-facing tools and lacks clear documentation of what 'runtime' means. No output schemas are documented. Error handling is minimal, divide raises ValueError on zero division, but the tool description does not warn about this or guide recovery.

• Expand parameter descriptions to 50-100 characters each. For add/subtract/multiply/divide, specify: 'A numeric value (integer or decimal). Negative values are accepted.' For divide, add: 'The divisor. Must be non-zero; passing 0 will raise an error.'
• Document the divide error case in the tool description: 'Divide a by b. Returns a float. Raises an error if b is 0, ask the user to provide a non-zero divisor.'
• Redesign current_datetime to accept a timezone parameter as a string (e.g., 'America/New_York') instead of a ToolRuntime object. This makes the tool usable by LLMs without framework-specific knowledge.
• Add output schema documentation for each tool. E.g., 'Returns: a float representing the sum of a and b.' For current_datetime: 'Returns: an ISO 8601 datetime string in the specified timezone.'
• Expand tool descriptions to 100-150 characters. E.g., 'Add two numbers together. Accepts integers and decimals. Returns the sum as a float. Use this when the user asks to add, sum, or combine numeric values.'