XLSX Formula Checker

Connection availability

Open XLSX Formula Checker on Claude from the Claude directory.

The remote endpoint supports direct connections from compatible MCP clients. Add it using the steps below.

Connect your MCP client

Use this exact remote MCP endpoint:

In a client that supports custom remote MCP connections, add a connector named XLSX Formula Checker with this URL. This endpoint uses Streamable HTTP and no authentication, so it does not ask you to sign in to Workbook Tools or supply an API key. Your client and organization settings determine whether custom connections are available.

Start by asking your assistant to call xlsx_capabilities. Then supply a small workbook explicitly and ask it to inspect the workbook before calculating.

What you can check

• xlsx_capabilities: discover supported functions, tool inputs and limits.
• xlsx_inspect_workbook: inspect sheets and formula context in a supplied XLSX.
• xlsx_read_range: read a bounded cell range, including source formulas and saved results.
• xlsx_check_workbook: check formulas on a disposable copy, distinguish calculated errors from stored errors and missing caches, and report when validation cannot run. This does not certify business logic or cache freshness.
• xlsx_calculate_workbook: calculate selected outputs using supported formulas and distinguish new results from saved workbook caches.
• xlsx_run_scenario: replace selected literal inputs in memory and compare selected calculated outputs.

Calculation uses the same Rust workbook engine as the local editor. Its formula support is partial. The browser editor runs this shared engine as WebAssembly; the remote service runs it natively. Unsupported formulas or workbook features can prevent calculation; the tool reports the limitation. Macros and external data connections are not executed. Results are not a guarantee of Microsoft Excel parity.

Supply the workbook explicitly

Supply either an inline workbook with named sheets and explicit cell values/formulas, or a workbook_base64 argument containing standard base64-encoded XLSX bytes. A file name, local path, web link or assistant attachment reference is not enough. Opening a file in our local editor does not send it to this MCP.

For a small formula question, your assistant can build this fictional inline workbook directly from your supplied cells:

{
  "workbook": {
    "sheets": [
      {
        "name": "Forecast",
        "cells": [
          {
            "address": "B2",
            "value": 100
          },
          {
            "address": "B3",
            "value": 2
          },
          {
            "address": "B10",
            "formula": "=B2*B3"
          }
        ]
      }
    ]
  },
  "outputs": [
    {
      "sheet_index": 0,
      "address": "B10"
    }
  ]
}

Ask your assistant to pass that object to xlsx_calculate_workbook. Cells use A1 addresses; outputs and scenario edits use a zero-based sheet_index. Provide one workbook input type per call.

The remote service receives the supplied cells or workbook. It does not browse your device, fetch workbook URLs or automatically read assistant attachments. Keep confidential data out of examples unless you are authorized to share it. Workbook calls are stateless and do not save edited workbooks or change your original file.

Workbooks support the full Excel worksheet address grid: 1,048,576 rows and 16,384 columns, through XFD1048576. Sparse cells can use these addresses without filling the intervening grid.

Remote calls accept up to 64 MiB of compressed XLSX data, 512 MiB expanded, 1,024 sheets and 2,000,000 occupied cells. A range read returns at most 2,000 cells per page, including empty positions. Set offset and limit to page through any range in row order. Continue with pagination.next_offset until it is null. Calculation and scenarios accept up to 500 output addresses; scenarios change up to 500 existing literal input cells and cannot replace formula cells.

Inline formulas accept up to 8,192 characters; literal text accepts up to 32,767 UTF-16 units. Supply every referenced input explicitly, using value: null for an intentional blank. Inline formula references are limited to 2,000,000 input-cell occurrences in total.

The full address grid does not mean that every cell can be populated or calculated in one call. Formula evaluation has a 512 MiB calculation memory budget and a 30-second calculation deadline; the service also enforces process resource limits. Use xlsx_capabilities for the current engine details.

Optional AI formula help

When enabled, xlsx_formula_help accepts a question, formula and optional text context. Those explicit inputs go from our server to an external formula assistance service. See our privacy policy for its service providers and data handling. The server keeps our API credential secret; you do not provide a key. Workbook bytes are not automatically attached to AI help.

AI suggestions can be wrong and do not replace deterministic checks. AI help has separate availability and rate limits. See our privacy policy for the remote processing boundary.

Example questions

• “Inspect this explicitly supplied workbook and tell me which sheets and formula issues it contains.”
• “Calculate Forecast!B10, then compare it with the value saved in the file.”
• “What happens to Forecast!B10 if the existing literal input Forecast!B2 changes from 100 to 120?”

The MCP does not control Microsoft Excel, Microsoft 365 or OneDrive. It does not edit or save a local workbook. Operated by Shipit Software Limited. See Workbook Tools support.