GridPath

Docs

GridPath docs.

GridPath is an MCP server that lets an agent edit the .xlsx and .xlsm files you already have, with a review step before anything is written. It runs wherever Node runs, evaluates formulas in process, and saves by patching the original file so charts, pivots, macros and everything else come back byte-identical.

Quick start

One line in Claude Code:

claude mcp add gridpath -- npx -y gridpath mcp --review-required

Then ask the agent to change a workbook. It reads the file, writes the change as a pending batch, and hands you a local review link. Open it, look at every changed cell before and after, reject what you don't want, and save.

Claude CodeOne command, works in every project. Claude DesktopDownload a bundle, no terminal needed. CursorOne-click install or a line in mcp.json. CodexThree lines in config.toml.

How it works

  1. Open. The first call on a file parses it into an in-process calculation engine, a fork of IronCalc compiled to WebAssembly. No Excel, no LibreOffice, no Python.
  2. Read. The agent orients with describe_workbook and find_rows, filters data with query_rows, and reads exact cells with read_range. Values are evaluated, so the agent sees what Excel would show.
  3. Write. Every write tool lands as a pending batch in memory and returns a readback of what it wrote, plus a review_url. The file on disk is untouched.
  4. Review. The review page shows the workbook with changed cells highlighted and before/after for each one. Accept or reject per batch or per cell.
  5. Save. save_workbook diffs the model against the file as loaded and patches only the zip parts an edit touched. Everything else is copied through unchanged.

Guides

Review before saveBatches, the review page, review-required mode, save and save-as. Reading a workbookThe four read tools and the order to call them. Writing cells and formulasset_cell, set_range, copy_range, and what the readback tells you. run_scriptSandboxed JavaScript for loop-shaped edits, one batch. Formatting and layoutNumber formats, fills, widths, freezes, merges, notes, names. Rows, columns and sheetsInsert, delete, create, rename, and what shifts.

Reference

Other hosts

Gemini CLI, Windsurf, VS Code and any other MCP host that speaks stdio use the same command and arguments in that host's MCP settings:

{ "mcpServers": { "gridpath": { "command": "npx", "args": ["-y", "gridpath", "mcp", "--review-required"] } } }

Requirements

  • Node 20 or newer, on macOS, Windows or Linux. The Claude Desktop bundle ships its own Node.
  • Files: .xlsx and .xlsm. Macros, pivots, charts and add-in data are preserved, not edited.

Source is public at github.com/pixelsmasher13/gridpath under FSL-1.1-Apache-2.0. GridPath is also a desktop app with the same engine and review and its own agent built in.

Found a mistake? Open an issue or email support@gridpath.dev.