Niblet MCP server has well-structured tool definitions with consistent naming (verb_noun pattern: niblet_search, niblet_materials, etc.) and comprehensive descriptions (100-150 chars each). All 6 tools have input schemas with typed parameters and descriptions. However, output schemas are not documented in the visible code, only input schemas are shown. Error handling is present (authenticationFailed, httpError functions) with actionable guidance, but tool descriptions lack dependency hints and prerequisites. Tool annotations (readOnlyHint, idempotentHint, openWorldHint) are declared but not visible in individual tool registrations. Parameters are well-described but lack explicit enums for categorical values (e.g., 'platform' in niblet_references could be an enum: iOS|Android|web).

• Document output schemas for all tools. For niblet_search, specify: { results: [{ id: string, title: string, category: string, license: string, url: string }], total: number, limit: number }. Include field descriptions and types.
• Convert categorical parameters to enums. Change 'platform' description to enum: ['iOS', 'Android', 'web', 'desktop'] and 'license' to enum: ['MIT', 'Apache-2.0', 'CC-BY-4.0', ...]. Prevents hallucinated values.
• Add dependency hints to tool descriptions. E.g., niblet_design_reference: 'Retrieve detailed information about a specific design reference. First call niblet_search() or niblet_references() to obtain a reference ID.'
• Add pagination parameters and document limits. Add 'offset' and 'limit' (default 10, max 50) to niblet_search, niblet_materials, niblet_references. State in descriptions: 'Returns up to 50 results per call. Use offset to paginate.'
• Verify tool annotations are applied per-tool in registration. Ensure each tool's definition includes readOnlyHint: true, idempotentHint: true, openWorldHint: true in the tool registration call to McpServer.tool().