GridPath

Let AI edit the Excel files you already have: faster, for fewer tokens, and you get them back intact.

GridPath is an engine for editing real .xlsx files. Give it to your coding agent and the same edit takes a fraction of the time and tokens, because the agent calls spreadsheet tools instead of writing and debugging scripts:

• Faster and cheaper. An in-process calculation engine and purpose-built tools (workbook map, row search, structural edits) replace the write-a-script, run-it, recalculate-somewhere-else loop.

• Intact. A surgical saver rewrites only the parts an edit touched; charts, pivots, VBA, add-in data and everything else come back byte-identical.

• Reviewed. You see every changed cell, before and after, and nothing is written until you accept.

Claude Code (Sonnet 5.5) on a real 1.4 MB, 55,000-formula analyst model, same prompt with and without GridPath:

Both lanes got every edit right. The difference is time, tokens, and seeing the diff before it's saved. Full runs, including the ones we lose, are in the evals repo.

It comes as two front doors on the same engine:

Source-available under the FSL-1.1-Apache-2.0; each release becomes Apache 2.0 after two years.

MCP server

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

Your agent edits the real .xlsx through GridPath's tools (describe, find, read, write, run_script, structure ops). Every change returns a readback and a review link: changed cells before/after, accept or reject per batch, save. Nothing is written until you save; with --review-required only the review page can save. No Python, no LibreOffice, no Excel needed. Details, host config snippets and the tool list: packages/gridpath/README.md.

Related MCP server: Excel MCP Server

Desktop app

Open a .xlsx, type what you want, review the diff, accept it. Multiple workbooks side by side, each with its own agent; other files attachable as read-only references. Your file never leaves your machine, and it works with the Claude or ChatGPT subscription you already pay for.

Download GridPath

What the app does

• Multi-workbook — Workbooks side by side, each with its own agent. Attach others as read-only references.

• Reversible changes — Diff-first edits. Accept, reject or use ⌘Z. Nothing saves until you say so.

• Spreadsheet-native harness — With the same model, GridPath ran 3.9–14× faster in our benchmarks and used 95–96% fewer output tokens on edit tasks.

• Workbook fidelity — Surgical saves rewrite only what changed; charts, pivots, formatting, VBA and plugin data stay intact.

• Formula-first — Writes formulas, not pasted numbers, so models stay live.

• Local-first — Your .xlsx stays on disk. Only your prompt and the cells the agent needs go to Claude or OpenAI.

How it compares

Best-effort comparison as of September 2026. The "preserves" and "diff" rows for coding agents are measured, not inferred — see the benchmark repo. On the August 2026 models a headless coding agent silently dropped parts of a workbook in 2 of 5 edit runs; on Sonnet 5.5 (September 2026) it preserved every part in all of our runs by choosing XML surgery on its own. GridPath preserves them by construction, not by the model's judgment on the day.

Project status

Under active development. Editing existing workbooks — the case above — is the strongest path and the one under continuous benchmark. Building large multi-sheet models from scratch works but is improving; the benchmark repo publishes those results too, including the ones we lose.

Source availability and license

Source-available under the Functional Source License, Version 1.1, with Apache 2.0 Future License (FSL-1.1-Apache-2.0):

• You can read, fork, modify, run and redistribute the source for any non-competing use, including commercially.

• You can't ship it, or a substantially similar fork, as a paid product competing with GridPath.

• In two years every release re-licenses to Apache 2.0, no restrictions.

If you want to use GridPath in a way the FSL doesn't permit, get in touch.

Build from source

Requires Node 20+, Rust stable via rustup, and your platform's Tauri prerequisites.

npm install
npm run tauri dev

npm run tauri build produces a local unsigned build. On first launch, connect Claude with OAuth or an API key, or use the ChatGPT sign-in flow. Credentials stay in the local SQLite database.

Architecture

GridPath uses Tauri 2 with a Rust core, React and TypeScript, a vendored IronCalc fork (MIT/Apache-2.0), and SQLite. The surgical .xlsx patcher is in src-tauri/src/engine/workbook/xlsx_patch/, the agent loop in src-tauri/src/engine/spreadsheet_agent/, and the benchmark harness in eval/.