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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' returns text, not structured error). Tool names lack action verbs ('add' and 'calculate' are weak; 'perform_addition' and 'perform_calculation' would be clearer). No parameter descriptions beyond type hints. Schemas are visible and properly typed, preventing a lower score, but the overall quality is below community baseline.
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 entirely. Parameters 'a', 'b', and 'operation' have no descriptions beyond type hints. 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 schemas are not documented. Callers cannot predict the response structure. Document that both tools return {content: [{type: 'text', text: string}]} and that 'calculate' may return error messages for division by zero.
| Scored | Grade | Overall | Spec posture | Rubric |
|---|---|---|---|---|
| 2026-09-23 | F | 49 | 2026-07-28+ | v2 |
Tool names lack action verbs. 'add' and 'calculate' are weak; they do not clearly signal intent. Rename to 'perform_addition' or 'add_numbers' and 'perform_arithmetic' or 'calculate_result' to match verb_noun convention and improve LLM discoverability.
Error handling for division by zero returns plain text ('Error: Cannot divide by zero') instead of a structured error response. LLMs cannot distinguish success from failure or determine if the call is retryable. Return a structured error with error_code and recovery guidance.