Excel MCP Server (excel-mcp-rw)

High-Performance Read & Write Model Context Protocol (MCP) Server for Microsoft Excel on Windows.
Powered by Pandas, OpenPyXL, and Native Windows Microsoft Excel Automation (COM / PyWin32).

⚡ Why This Server?

Most Excel MCP servers are lightweight JavaScript wrappers that fail on real-world spreadsheets:

• ❌ They crash or exceed LLM context windows on large multi-megabyte files.

• ❌ They cannot calculate dynamic Excel formulas (=XLOOKUP, =FILTER(), dynamic arrays, complex nesting).

• ❌ They cannot refresh PivotTables or external database connections.

• ❌ They cannot run VBA macros (.xlsm) or export pixel-perfect PDFs.

excel-mcp-rw solves this with a Dual-Engine Architecture:

1. Engine 1: Fast Python Data Science Stack (pandas + openpyxl)

   • Instant metadata streaming without loading multi-GB spreadsheets into RAM.

   • Vectorized filtering (df.query()) and column statistics at compiled C-speed.

   • Bounded pagination so the model never blows its context window.

2. Engine 2: Native Microsoft Excel Engine (COM Automation via pywin32)

   • Uses real Windows Microsoft Excel to execute Application.CalculateFull().

   • Refreshes PivotTables and data connections (wb.RefreshAll()).

   • Native print-engine PDF export.

   • Runs VBA macros and inspects active workbooks open on the desktop.

Related MCP server: BachStudio Excel MCP Server

🛠️ Available Tools

📊 Data Analysis & Manipulation (pandas / openpyxl)

🔄 Multi-Key Reconciliation & Discrepancy Matching (pandas + RapidFuzz)

🪟 Native Windows Microsoft Excel Tools (COM / PyWin32)

📋 Best-Practice Agent Workflow for Reconciliations

When asking your AI assistant to compare or reconcile two workbooks (e.g. Purchase Orders vs SAP/ERP records):

1. Step 1: Pre-Flight Analysis
   The agent calls analyze_reconciliation_keys(file_1, file_2, join_keys=['PO_Number', 'SAP_Code']) to diagnose key overlap, formatting quirks, and duplicate keys.

2. Step 2: Diagnosis & Strategy Alignment
   The agent reports match percentage and any recommendations (e.g. "5 rows have whitespace differences; 2 rows need fuzzy matching").

3. Step 3: Execute & Generate 3-Tab Audit Workbook
   The agent runs reconcile_and_merge to produce:

   • 1_Reconciled_Matches: Exact matches + calculated price/qty differences.

   • 2_Probable_Fuzzy_Matches: Near matches flagged for human review with confidence %.

   • 3_Unmatched_Exceptions: Records missing in either file.

🚀 Quickstart & Installation

1. Clone & Install Dependencies

git clone https://github.com/indala/excel-mcp-rw.git
cd excel-mcp-rw
pip install -r requirements.txt

⚙️ Client Configurations

1. Claude Desktop

Add this to your %APPDATA%\Claude\claude_desktop_config.json:

{
  "mcpServers": {
    "excel": {
      "command": "python",
      "args": [
        "C:/path/to/excel-mcp-rw/src/excel_mcp/server.py"
      ]
    }
  }
}

2. Claude Code CLI

Add globally to your user scope:

claude mcp add -s user excel -- python C:/path/to/excel-mcp-rw/src/excel_mcp/server.py

3. Google Antigravity

Add to ~/.gemini/config/mcp_config.json:

{
  "mcpServers": {
    "excel": {
      "command": "python",
      "args": [
        "C:/path/to/excel-mcp-rw/src/excel_mcp/server.py"
      ]
    }
  }
}

4. Cursor / Windsurf

Add a new STDIO server in your MCP settings:

• Name: excel

• Type: command (or stdio)

• Command: python C:/path/to/excel-mcp-rw/src/excel_mcp/server.py

📝 Example Prompts

Once connected to your assistant, you can ask:

• "Give me an overview of all sheets in C:/reports/financials_q3.xlsx without loading the whole file."

• "Filter the Transactions sheet for Amount > 10000 and Status == 'Pending', and give me the top 20 rows."

• "What is the statistical distribution of the 'Salary' column in our employee database?"

• "Search for customer ID 'CUST-8492' across all sheets and tell me which row it appears on."

• "Recalculate all formulas in this sheet using native Excel and export it to PDF."

• "What Excel spreadsheet do I currently have open on my desktop?"

📄 License

This project is licensed under the MIT License.