Excel
Excel is a community MCP server from negokaz that lets an assistant read and edit real .xlsx workbooks over stdio: describe the sheets, read a range, write cells, copy a sheet, create a table, apply formatting. It runs through npx, touches files on your disk directly, and needs no account, no API key and no cloud service.
How we started it
npx -y @negokaz/excel-mcp-serverUse it if your spreadsheets already live as files on the machine the agent runs on. Six tools, all of them things a person actually does to a workbook, and the whole tools/list costs ~1,406 tokens (chars/4 estimate, measured 2026-08-19), which is cheap for write access to a binary format nobody wants to parse by hand. The cost is the version we booted: 0.12.0-SNAPSHOT-1ff4340, a snapshot build handing an LLM write access to files it cannot undo. Keep it away from anything you have not committed or copied first.
Use it if
Skip it if
The bill for your context window
| Tool | Est. tokens | Described? | Required params |
|---|---|---|---|
| excel_format_range | ~614 | yes (54 chars) | 4 |
| excel_write_to_sheet | ~229 | yes (31 chars) | 5 |
| excel_read_sheet | ~184 | yes (45 chars) | 2 |
| excel_create_table | ~152 | yes (33 chars) | 3 |
| excel_copy_sheet | ~134 | yes (34 chars) | 3 |
| excel_describe_sheets | ~92 | yes (50 chars) | 1 |
At ~1,406 estimated tokens for six tools, the tax here is proportionate: you are paying roughly one short page of context for read plus write plus formatting on a format the model otherwise cannot open. The weight is lopsided, though. excel_format_range alone accounts for ~614 of those tokens, more than six times what excel_describe_sheets costs at ~92, because its schema has to enumerate every styling knob. If you only ever read and write values, that formatting schema is the one thing worth trimming from your tool list.
Setup reality
About as light as MCP setup gets. The command is npx -y @negokaz/excel-mcp-server, transport is stdio, and when we started it the harness passed a clean env with no secrets and it came up anyway: no envHints appeared in stderr, no key, no token, no login. What you do have to think about is the working directory and file paths, since every tool addresses a workbook by path, and the process runs with whatever filesystem rights you gave it. Run it as a user that can only reach the directory holding the spreadsheets you meant to expose.
Questions people ask
Does the excel MCP server need Microsoft Excel installed?
No. It reads and writes the .xlsx file itself, so it works on a headless Linux box with no Office install and no Microsoft account. It also means it never touches workbooks stored in OneDrive or SharePoint unless those files are synced down to local disk first.
Can it break my spreadsheet?
Yes, in the ordinary way any program with write access can. The write and format tools edit the file in place, and nothing in the protocol offers a rollback. Point it at a copy, or keep the workbook under version control, and you get the upside without the bad afternoon.
Which tools does it expose?
Six: excel_describe_sheets, excel_read_sheet, excel_write_to_sheet, excel_create_table, excel_copy_sheet and excel_format_range. That covers inspecting a workbook, moving values in and out, and styling ranges. Formula evaluation and chart editing are not in that list.
Other files servers we started
| Server | Vendor | Boots | Context tax |
|---|---|---|---|
| Filesystem | Anthropic (reference) | ✓ | ~3,243 tokens |
| Google Drive (archived) | Anthropic (archived) | ✗ | ~0 tokens |
How this page is made: the server is spawned as an unprivileged user with a clean environment and no credentials, then asked for its tools, resources and prompts over stdio. Token figures are estimates at four characters per token, not a tokenizer count. One run, one machine. Corrections: contact the desk.