graph-excel-mcp
MCP server for reading and editing Excel workbooks on SharePoint, OneDrive or Teams through Microsoft Graph, without a browser. It is written in TypeScript, has no runtime dependencies, and runs on Node 18 or later.
It is built for workbooks that several people edit at once:
- Every write starts as a dry run.
- Before writing, it checks the cells' current content against the version you read, so it won't overwrite someone else's edit.
- After writing, it reads the cells back to confirm the change.
Install
Claude Code / any MCP host (stdio):
claude mcp add --scope user graph-excel -- npx -y graph-excel-mcp
{ "mcpServers": { "graph-excel": { "command": "npx", "args": ["-y", "graph-excel-mcp"] } } }
Claude Desktop extension: download graph-excel-mcp-<version>.mcpb from the latest release and open it.
Claude plugin (Cowork, Claude Code): install the plugin/ folder of this repo. It contains the server and a graph-excel skill.
Sign in
Call the login_status tool, or run npx graph-excel-mcp login, then enter the code it shows at https://login.microsoft.com/device. The refresh token is saved in ~/.graph-excel/token.json with mode 600. Set GRAPH_EXCEL_HOME to keep it somewhere else.
Sign-in uses the Microsoft Graph PowerShell public client with the delegated scope Files.ReadWrite.All, so you don't need to register an app. If your tenant blocks user consent, an admin has to approve that client once.
Workbook aliases
Instead of pasting the SharePoint URL every time, you can add aliases to ~/.graph-excel/workbooks.json (see workbooks.example.json). The resolve tool returns the driveId and itemId you need for an alias.
Tools
| Tool | What it does |
|---|---|
login_status | Checks the token, or starts a device code login |
resolve | Returns drive/item ids, last modified, and the sheets with their used ranges |
read_range | Returns values plus a sha256: hash per cell, and fills on request |
write_values | Writes blocks of values with a base check (expected) and read-back verification |
append_update | Adds or replaces a 「-----update-----」 section under a cell's existing text, keeping the original part byte-identical, and can fill the row with a color |
set_fill | Sets or clears the fill color of one or more ranges in a single batch |
Notes
- Every call runs inside a workbook session. Sessionless calls on large workbooks can time out with a 504 even though the write was applied.
- Line breaks are sent as
\n, which Excel stores as\r\n. If you write\r\ndirectly, the cell ends up with a stray_x000D_.
Development
Development needs Node 22.18 or later, which runs the .ts sources directly.
| Command | What it does |
|---|---|
npm run mcp / npm run login | Runs the server or the terminal sign-in from src/ |
npm run typecheck | Runs tsc in strict mode with no emit |
npm test | Runs offline tests: range parsing, update composition, and the MCP handshake on src/ and dist/ |
npm run build | Compiles src/ to dist/, which is what npm, the .mcpb and the plugin run |
npm run pack | Builds, then writes build/*.mcpb (gitignored) and plugin/ (committed) |
Layout:
| Path | Contents |
|---|---|
src/graph.ts | Auth and the Graph client |
src/excel.ts | Workbook operations |
src/mcp.ts | Tools and the JSON-RPC server |
src/cli.ts | Entry point |
Release
Bump version in package.json, run npm run pack, commit, then push a matching tag:
git tag v0.3.1 && git push origin v0.3.1
The Publish workflow runs the tests, publishes to npm through trusted publishing (no token or OTP; provenance attached) and creates a GitHub release with the .mcpb attached.
License
MIT