The server defines 7 tools with clear verb-noun naming (list_, read_, write_, describe_, export_, current_). All tools have descriptions (avg ~120 chars, within baseline 34-392). Input schemas are present with type declarations. However, parameter descriptions are sparse or missing entirely, most parameters lack explanatory text beyond the type. Output schemas are undocumented; the code shows text() and failure() helpers but no formal schema definitions for tool responses. Error handling is basic (isError flag + text message) without recovery guidance or categorization. The workbook hash collision-detection pattern in write_workbook is sophisticated but underdocumented for LLM reasoning.

• Document output schemas for all tools. Define what fields each tool returns, their types, and structure. E.g., list_workbooks should return {workbooks: [{id: string, path: string}], total: number}. Use JSON Schema or TypeScript interfaces in comments.
• Add parameter descriptions to every input. For 'id' param, explain: 'Workbook identifier (directory name under sheets/). Call list_workbooks to discover valid IDs.' For 'sheet', add: 'Sheet name as shown on its tab. Call describe_workbook to list available sheets.'
• Enhance error messages with recovery guidance. Instead of failure(error), return {isError: true, message: error.message, suggestion: 'Try calling list_workbooks() to verify the workbook ID exists.', retryable: true/false}.
• Document the hash collision-detection pattern. Add to write_workbook description: 'If hash does not match (concurrent edit detected), the write is refused. Re-read the workbook with read_workbook, merge changes, and retry.'
• Add descriptions to enum values. For export_workbook format param: 'Output format: xlsx (live formulas, base64-encoded), csv (first sheet only, computed values), or html (rendered view, text).'
• Consider adding a discovery tool or enriching describe_workbook to return cell references and named ranges, so LLMs can construct read_sheet calls without trial-and-error.