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.
In an Agent Plugins host, the runtime is downloaded and cached under PLUGIN_DATA\runtime; release freshness is checked once per Copilot session. The optional global shim falls back to ~\.copilot\plugin-runtime\mcp-server-excel\excel-cli and checks for updates at most once every 24 hours.