render-mcp demonstrates solid definition quality with consistent tool naming, descriptions, and input schemas. All 6 tools follow verb_noun naming conventions (render_*). Every tool has a non-empty description (range: 87 - 179 chars, within the 10 - 1024 baseline). Input schemas are properly defined using Zod with type constraints and descriptions for all parameters. However, output schemas are not documented in the source code, and error handling guidance is absent, typical gaps that prevent this from reaching the 80+ range. The render_pdf_smart tool is notably sophisticated, offering multiple modes (hybrid/render/text) with clear descriptions of the token-efficiency trade-offs. Tool annotations (readOnlyHint, openWorldHint) are applied appropriately to all tools, showing good attention to agentic patterns.

• Document the return type for each tool. Example: 'render_image returns {data: base64_string (PNG), media_type: "image/png", size_bytes: number}'. Add this to tool descriptions or create a separate API documentation file.
• Add error handling examples and recovery guidance to tool descriptions. E.g., render_pdf: 'If the file is not found or unreadable, returns an error with the absolute path that was checked. If pdftoppm is not installed, returns installation instructions.'
• Validate and document path handling. State in descriptions: 'path must be an absolute path on the server filesystem. Relative paths and path traversal (../) are rejected.' Consider adding a note about sandboxing if applicable.
• Clarify mutual exclusivity for html/path and svg/path parameters. Update descriptions: 'Exactly one of html or path must be provided. If both are present, html takes precedence. If neither is provided, returns an error.'
• For render_pdf_smart, document page limits and approximate token cost. Example: 'Returns up to 10,000 tokens of text and images. For PDFs >100 pages, use the pages parameter to request specific ranges.'
• Add idempotentHint annotations to all tools where applicable (all 6 appear to be read-only and side-effect-free, so they are implicitly idempotent, make this explicit in tool metadata).
• Create a handler test suite (src/handlers/*.test.ts) to document expected outputs and error cases. This will be visible in the repo and serve as de-facto API documentation.