This server has a single tool (nvd_tool) with minimal definition quality. The tool name lacks an action verb, is vague about its function, and does not follow the verb_noun naming convention. The description is adequate but brief. The input schema is present and properly typed, but lacks validation constraints. Error handling is absent, the tool returns None on failures with no guidance for recovery. The implementation has critical issues: it uses a singleton pattern for the NVD class (poor design), returns raw string representations instead of structured output, and provides no pagination despite potentially large result sets. The tool name 'nvd_tool' is generic and does not convey the action (fetch, search, lookup) or what CVE means in the context.

• Rename 'nvd_tool' to 'get_cve' or 'search_cve' to follow verb_noun convention and clarify intent.
• Update tool description to explain WHEN to use it (e.g., 'Retrieve detailed vulnerability information for a specific CVE ID from the National Vulnerability Database.') and add prerequisites (e.g., 'Requires a valid CVE ID in format CVE-YYYY-NNNNN.').
• Add format constraint to cve_id parameter description: 'The CVE identifier in format CVE-YYYY-NNNNN (e.g., CVE-2025-1234). YYYY must be 2002 or later.'
• Document output schema as a JSON object with typed fields: {cve_id: string, description: string, severity: string, published_date: string, last_modified_date: string, ...}. Return structured TextContent with JSON payload, not raw string representation.
• Replace unstructured error handling (print statements and None returns) with explicit error messages. Return TextContent with error details: 'Error: Rate limit exceeded (HTTP 403). Try again after 5 minutes.' or 'Error: CVE not found. Verify the ID matches format CVE-YYYY-NNNNN.'
• Remove singleton pattern from NVD class. Make each instance independent and thread-safe.
• Add pagination: accept optional 'limit' parameter (1-100, default 20) and return per-item results with a total_count field. Document in description: 'Returns up to 20 vulnerabilities per call. Use pagination to retrieve all results.'
• Add input validation: check cve_id format server-side before calling the API. Return a clear error message if format is invalid (e.g., 'Invalid CVE ID format. Expected CVE-YYYY-NNNNN.').

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry