Excel Automation with excelcli

Preconditions

Windows host with Microsoft Excel installed (2016+)
Uses COM interop — does NOT work on macOS or Linux
Every command below invokes excelcli directly, so it must resolve on PATH. Installing the excel-cli plugin does not put it there — the global shim is opt-in. Run com.github.copilot\bin\install-global.ps1 from the installed plugin folder once (it writes excelcli.cmd / excelcli.ps1 into ~\.copilot\bin and adds that to your user PATH), or install the runtime independently via the standalone release zip or dotnet tool install --global Sbroenne.ExcelMcp.CLI. If excelcli is not found, report that and stop — do not guess at a path.
The runtime itself is downloaded and cached on first use under ~\.copilot\plugin-runtime\mcp-server-excel\excel-cli, so only the first invocation needs network access