Excel MCP Server

Instructions

Implementation Reference

• src/handlers/file-operations.ts:171-238 (handler)

  The core handler function that implements the write_multi_sheet tool. It creates an Excel workbook with multiple sheets, adds data and headers to each sheet, applies formulas to specified cells, and writes the file to disk.
  async writeMultiSheet(args: ToolArgs): Promise<ToolResponse> { const { filePath, sheets, sheetReferences = true } = args; const ext = path.extname(filePath).toLowerCase(); const absolutePath = path.resolve(filePath); if (ext !== '.xlsx' && ext !== '.xls') { throw new Error('write_multi_sheet only works with Excel files (.xlsx or .xls)'); } const workbook = new ExcelJS.Workbook(); const sheetInfo: any[] = []; // First pass: Create all sheets with data for (const sheetDef of sheets) { const { name, data, headers, formulas } = sheetDef; // Prepare data with headers if provided const fullData = headers ? [headers, ...data] : data; // Create worksheet const worksheet = workbook.addWorksheet(name); // Add data to worksheet fullData.forEach((row: any[]) => { worksheet.addRow(row); }); // Apply formulas if provided if (formulas && Array.isArray(formulas)) { for (const formulaDef of formulas) { const { cell, formula } = formulaDef; // Set formula in worksheet const excelCell = worksheet.getCell(cell); // If the formula starts with =, remove it for ExcelJS const cleanFormula = formula.startsWith('=') ? formula.substring(1) : formula; excelCell.value = { formula: cleanFormula }; } } sheetInfo.push({ name, rowCount: fullData.length, columnCount: (fullData.length > 0 && fullData[0]) ? fullData[0].length : 0, formulaCount: formulas?.length || 0, }); } // Write the workbook await workbook.xlsx.writeFile(absolutePath); return { content: [ { type: 'text', text: JSON.stringify({ success: true, filePath: absolutePath, mode: 'multi-sheet-advanced', sheetsCreated: sheets.length, sheetReferences: sheetReferences, sheets: sheetInfo, totalFormulas: sheetInfo.reduce((sum, sheet) => sum + sheet.formulaCount, 0), }, null, 2), }, ], }; }
• src/index.ts:632-694 (schema)

  The input schema definition for the write_multi_sheet tool, specifying parameters like filePath, sheets (with data, headers, formulas), and sheetReferences.
  name: 'write_multi_sheet', description: 'Create a complex Excel file with multiple sheets, formulas, and inter-sheet references', inputSchema: { type: 'object', properties: { filePath: { type: 'string', description: 'Path for the new Excel file (must end with .xlsx or .xls)', }, sheets: { type: 'array', description: 'Array of sheet definitions', items: { type: 'object', properties: { name: { type: 'string', description: 'Sheet name', }, data: { type: 'array', description: 'Array of arrays representing rows of data', items: { type: 'array', }, }, headers: { type: 'array', description: 'Optional headers for the first row', items: { type: 'string', }, }, formulas: { type: 'array', description: 'Array of formula definitions', items: { type: 'object', properties: { cell: { type: 'string', description: 'Cell address in A1 notation (e.g., "A1", "B5")', }, formula: { type: 'string', description: 'Excel formula (e.g., "=SUM(A1:A10)", "=Sheet1!A1+Sheet2!B2")', }, }, required: ['cell', 'formula'], }, }, }, required: ['name', 'data'], }, }, sheetReferences: { type: 'boolean', description: 'Enable inter-sheet formula references (default: true)', }, }, required: ['filePath', 'sheets'], }, },
• src/index.ts:1247-1248 (registration)

  The switch case in the CallToolRequestSchema handler that routes calls to 'write_multi_sheet' to the FileOperationsHandler.writeMultiSheet method.
  case 'write_multi_sheet': return await this.fileOpsHandler.writeMultiSheet(toolArgs);
• src/index.ts:55-55 (registration)

  Instantiation of the FileOperationsHandler class instance used for file operations tools including write_multi_sheet.
  this.fileOpsHandler = new FileOperationsHandler();
• src/index.ts:15-15 (registration)

  Import of the FileOperationsHandler class containing the writeMultiSheet method.
  import { FileOperationsHandler } from './handlers/file-operations';