The ETH Library MCP server demonstrates solid definition quality with complete JSON Schema validation, clear verb-noun naming conventions, and extensive parameter documentation. All 6 tools are properly registered with explicit schemas and descriptions. However, descriptions are somewhat verbose (exceeding the 10-1024 character baseline in places), and output schemas lack explicit documentation of what fields are returned. Error handling is present but could be more prescriptive about recovery steps. Tool naming is consistently strong (search_*, get_*, list_*) and parameter constraints use proper enums and bounds.

• Add explicit output schema documentation to each tool. E.g. for search_resources, document: 'Returns an object with {results: [{id, title, creator, type, language, url}], total_count: number, has_more: boolean}'. This enables LLMs to plan chaining.
• Shorten search_resources description from ~280 chars to ~120 chars. Move operator and format details ('Felder: any, title, creator...') into the query parameter description itself, where they are directly actionable.
• Add explicit error handling section to tool descriptions where applicable. E.g. 'Errors: 404 if resource not found (try search_resources to find the ID); 429 if rate limited (retry after 60s); 400 if query syntax is invalid (see query parameter format rules).'
• Document list_resource_types and list_archives response structure. E.g. 'Returns: {types: [{key: string, label: string}]} for resource types; {archives: [{key: string, name: string}]} for archives.'
• Consider adding a 'recovery hints' parameter or inline note for search tools. E.g. 'If no results found, try broadening the query or removing filters. Use list_resource_types to see available resource types before filtering.'
• Add per-parameter min/max and constraint documentation to search_resources query param. The format 'Feld,Operator,Wert' with AND/OR/NOT operators is powerful but needs examples closer to the parameter definition, not the tool description.

Inferred effective spec: 2025-06-18+.

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