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A remote MCP server providing calculator tools without authentication, deployed on Cloudflare Workers
Two tools with basic schemas and minimal descriptions. Both tools have input schemas with proper types (number, string, enum), but descriptions are extremely short (10-40 chars), falling well below the 50-200 char baseline for LLM-optimized descriptions. No output schemas documented. Error handling is minimal (divide-by-zero check in 'calculate' only). Tool names lack action verbs ('add' and 'calculate' are weak; 'perform_addition' and 'perform_calculation' would be clearer). No parameter descriptions beyond type info. No composition guidance or chaining IDs. Schemas are visible and properly typed, preventing a lower score, but the overall quality is below community median.
Simple addition tool
Calculator tool with multiple operations
Tool descriptions are critically short (10-40 chars). 'Simple addition tool' and 'Calculator tool with multiple operations' lack context for LLM selection. Should explain WHAT the tool does, WHEN to use it, and what it returns (e.g., 'Adds two numbers and returns their sum as a numeric result. Use when you need basic arithmetic addition.').
Parameter descriptions are missing. Input schema defines 'a', 'b', and 'operation' with types but no descriptions. LLMs cannot infer that 'a' and 'b' are operands or that 'operation' must be one of the enum values. Add descriptions like 'First operand (numeric value)' and 'Arithmetic operation to perform: add, subtract, multiply, or divide'.
Output schema is not documented. Tools return text content but no schema is declared. LLMs need to know the response structure to plan downstream calls. Document: 'Returns a JSON object with a single text field containing the numeric result as a string.'
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | F | 40 | 2026-07-28+ | v2 |
Tool names lack action verbs. 'add' and 'calculate' are weak; they do not clearly distinguish intent. Rename to 'perform_addition' or 'add_numbers' and 'perform_arithmetic' or 'calculate_result' to match verb_noun convention and improve LLM disambiguation.
Error handling is minimal. Only 'calculate' checks for divide-by-zero; 'add' has no error handling. No guidance for LLMs on recovery. Add structured error responses: 'Invalid operation: got "modulo", must be one of: add, subtract, multiply, divide' and 'Cannot divide by zero. Please provide a non-zero divisor.'