Single-tool server with a well-structured schema and reasonable descriptions. The tool name is action-oriented (create_code_image), the description is clear and contextual (118 chars, within 10-1024 range), and all parameters have types and descriptions. However, the schema lacks error handling guidance, output structure documentation, and several parameter descriptions are thin (e.g., 'theme' lacks guidance on when to use each theme). Parameter constraints are enforced via defaults rather than enums, which is a missed opportunity for LLM self-correction. The tool performs a single, idempotent write operation with side effects (disk I/O), but the description does not explicitly state this. No output schema is documented, forcing the LLM to infer the structure of the returned image and filepath. Security and permission gates are absent, the tool writes to a user-specified output directory with no validation. Overall, the definition is functional but falls short of production-grade polish expected in a B+ tier.

• Convert theme parameter to z.enum(['dracula', 'monokai', 'github', 'solarized-dark', 'solarized-light']) to enforce valid choices and prevent LLM hallucination.
• Document the output schema explicitly in the tool description: 'Returns an object with fields: content (array of image and text), where image is base64-encoded PNG. Also returns filepath on disk.' Optionally add a formal output schema annotation if the SDK supports it.
• Add numeric constraints to width, height, and padding: 'width in pixels (minimum 100, default 800)', 'height in pixels (minimum 100, optional for auto-height)', 'padding in pixels (minimum 0, default 52)'.
• Update tool description to explicitly state side effects: 'Generates a code snippet image with syntax highlighting and styling, then saves it to disk in the specified output directory. Returns the image as base64 PNG and the filepath.'
• Add language fallback documentation: 'Programming language for syntax highlighting (e.g., javascript, python, typescript). If unsupported, code is rendered without highlighting.'
• Implement path validation in the generateImage function: reject outputDir paths containing '..', validate they are within a safe sandbox, and return a clear error message if traversal is detected.
• Add error handling with recovery guidance: wrap the highlight.js and Playwright calls in try-catch blocks. Return errors like 'Failed to highlight code in language "xyz": not recognized by highlight.js. Try "plaintext" or omit the language parameter for auto-detection.' Similarly for Playwright failures.