Architecture¶

Excel MCP Server uses Windows COM automation to control the actual Excel application — not just .xlsx files. Because it drives Excel's official COM API (Excel.Application), it can run live Excel operations — refresh Power Query, recalculate, refresh PivotTables and the Data Model, evaluate DAX, and run VBA or Python =PY() — and edit your existing workbooks with formulas, PivotTables, charts and macros left intact. You can watch Excel update in real time as the AI works.

Two equal entry points¶

The project ships both an MCP Server and a CLI. They are first-class, interchangeable entry points that share the same core, so every operation behaves identically no matter which you use:

• MCP Server hosts the service in-process — direct method calls, no pipe — which suits conversational, interactive AI clients.
• CLI (excelcli) talks to a background daemon over a named pipe, so sessions persist across invocations — ideal for scripted, high-throughput automation by coding agents.

flowchart TD
    A["AI assistants<br/>(Claude, Copilot, ChatGPT)"] -->|MCP protocol| B["MCP Server<br/>in-process service"]
    C["Coding agents<br/>(Copilot, Cursor, Windsurf)"] -->|excelcli| D["CLI<br/>named pipe → background daemon"]
    B --> E["Core Commands<br/>(shared codebase)"]
    D --> E
    E --> F["Excel COM API<br/>(Excel.Application)"]

Shared core, separate processes¶

Both entry points build on the same Core Commands codebase, so a feature added to one is automatically available to the other with the same parameters, defaults and validation. They run as separate processes, each managing its own Excel instance, and do not share live sessions with each other.

Ready to install? See the installation guide, or dive into the MCP Server and CLI references.