xlsx-tools-mcp

An MCP server for reading and writing Excel (.xlsx) files with high accuracy, while preserving the file’s existing structure, styles, and formulas.

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Overview

xlsx-tools-mcp exposes 29 Model Context Protocol (MCP) tools that give an LLM agent accurate, structure-preserving read and write access to Excel .xlsx files. It runs as a standard stdio MCP server: you install it and register it with an MCP client (Claude Code, OpenCode, etc.), and the client’s agent can list sheets, read cell ranges, search values, aggregate data, write cells/formulas, manage sheets/rows/columns, apply styles, and force formula recalculation.

It is built around the principle that editing an existing workbook should not destroy what it doesn’t touch.

Features

• Structure-preserving writes via openpyxl — writes load the existing workbook and save it back, preserving styles, merged cells, comments, and any aspect the edit doesn’t touch.
• Never-stale formula results via LibreOffice recalculation — openpyxl writes formula strings but never evaluates them. After every value/formula write the server runs a headless LibreOffice pass to recompute real results, then returns errors_found — any Excel error values (#REF!, #DIV/0!, #N/A, …) produced by the recalculation.
• Fast reads via python-calamine — a Rust-backed parser for accurate, fast type inference, with an automatic openpyxl fallback when you need formulas/styles/comments or when calamine can’t parse the file.
• pandas-based grouping/aggregation & querying — aggregate_sheet and query_sheet perform operations without destroying source structure, equipped with AST expression validation to block code injection.
• Native Excel objects — create formal Excel Tables (create_table) with autofilter and styles, and native charts (create_chart for bar, line, pie, scatter).
• Sheet lifecycle & formatting — rename sheets (rename_sheet), duplicate sheets with styles intact (copy_sheet), clear ranges (clear_range), and auto-fit column widths (autofit_columns).
• Cross-platform reliability (Windows, macOS, Linux) — case-insensitive path confinement, comma or semicolon ; environment delimiters, safe atomic file replacement with transient lock retry (WinError 32 / antivirus defense), and silent headless recalculation without window flicker.