Sketchpad has two well-named, verb-prefixed tools (read_file, write_file) with clear, detailed descriptions (150+ chars each) that explain WHAT, WHEN, and consequences. Both tools have input schemas with typed parameters and descriptions. Tool annotations (readOnlyHint, destructiveHint, idempotentHint) are correctly applied. However, the tools lack documented output schemas, and error messages are generic strings rather than structured guidance. The server demonstrates good naming discipline and parameter clarity but falls short of A-grade polish in error recovery and response documentation.

• Document output schemas formally. For read_file: return {"content": string, "size_bytes": integer, "exists": boolean}. For write_file: return {"success": boolean, "size_bytes": integer, "mode": string, "message": string}.
• Replace generic error strings with structured error objects: {"error": string, "code": string, "retryable": boolean, "suggestion": string}. E.g., 'Sketchpad too large' → {"error": "Storage limit exceeded", "code": "STORAGE_LIMIT", "retryable": false, "suggestion": "Reduce content size or contact admin"}.
• Remove example values from parameter descriptions. Change 'append (default) adds to the end with a newline separator' to just 'Append mode adds to the end with a newline separator; replace overwrites the entire file.' Let the enum and default constraint speak.
• Add optional limit and offset parameters to read_file to support pagination: read_file(limit: int = 1000, offset: int = 0) → {"content": string, "total_size": int, "returned_size": int, "has_more": bool}.
• Add a dry_run parameter to write_file: write_file(content, mode, dry_run=false). When true, validate and return predicted size without writing. Agents can preview before committing.