Single tool 'add' has a clear verb-noun name and basic schema with typed parameters (number, number). However, the description is extremely minimal (11 chars: 'Adds two numbers together'), falling below the 20-char threshold and providing no context on when/why to use it. No output schema is documented. No error handling guidance. No parameter descriptions beyond type hints. The tool is trivial (arithmetic) and lacks the depth expected even for demo servers. Baseline: A+ tools average 194 chars in description; this is 11.

• Expand tool description to 50 - 150 chars: 'Adds two numbers and returns the sum. Use for arithmetic calculations. Returns {result: number}. Handles integers and floats; returns error if inputs are NaN or Infinity.'
• Add parameter descriptions: a: 'First number to add (integer or float, no limit)', b: 'Second number to add (integer or float, no limit)'
• Document output schema in code and description: 'Returns {result: number}, the sum of a and b.'
• Add error handling: 'Returns error if either input is NaN, Infinity, or non-numeric. LLM should validate inputs before calling.'
• Replace trivial 'add' tool with domain-specific examples (e.g., calculate_invoice_total, estimate_project_cost) to demonstrate real-world utility and validate the workers-mcp framework.