The A2UI Catalog MCP server defines 4 tools with reasonable naming and descriptions, but has critical gaps in schema definition, parameter documentation, and error handling. Tool names follow verb-noun convention (list_, get_, validate_), which is positive. Descriptions are present but lack LLM-optimization specifics. Most critically: input schemas visible in tools.ts show only partial type information, the `AnthropicTool` interface declares `properties: Record<string, unknown>`, which means individual parameter types are not formally declared in the visible source. Parameter descriptions exist but are not comprehensive enough to guide LLM behavior. No output schemas are documented anywhere. Error handling is absent, no guidance on retryability, failure modes, or recovery steps. The tool set is READ_ONLY, which is safe but limits utility. Overall, this is a functional but underdeveloped tool suite typical of early-stage MCP servers.

• Formalize all parameter types in the schema object. Replace `Record<string, unknown>` with explicit property definitions including 'type', 'description', and 'enum' (where applicable). Example: {"component": {"type": "string", "description": "...", "enum": ["Button", "Card", ...]}}
• Document output schemas for each tool. For list_components, specify: 'Returns {"components": [{"name": string, "category": enum, "description": string}], "total": number, "limit": number}'
• Add pagination parameters to list_components: add optional 'limit' (default 20, max 100) and 'offset' (default 0) parameters, and return a 'total' count to enable pagination discovery.
• Enhance error descriptions. For validate_a2ui, specify expected error cases: 'Returns error if component does not exist (call list_components to see valid names), if props violate constraints, or if JSON is malformed (include suggestion for correction).'
• Remove example values from descriptions. Replace 'e.g., "Button", "Card", "TextField"' with an enum constraint in the schema. Replace 'e.g., "contact", "login"' with enum values in the intent parameter schema.
• Add a discovery note to get_component_schema: 'Call list_components first to discover available component names, then pass a name to this tool to get detailed prop schemas.'
• Document what validate_a2ui returns on success vs. failure. Specify the response structure: {"valid": boolean, "errors": [{"path": string, "message": string}]?, "suggestions": string[]?}'
• Declare tool safety attributes in tool definitions (if using MCP >=2026-07): add readOnlyHint: true and idempotentHint: true for all four tools (they are all read-only and safe to retry).