Office Addin MCP server

office-addin-mcp

Drive Excel, Word, Outlook, PowerPoint, and OneNote add-ins from any MCP client — through one Go binary that speaks the Model Context Protocol over stdio.

office-addin-mcp attaches to the WebView2 runtime that Office uses to host Office.js add-ins, then exposes a high-level tool surface to LLM clients. Instead of teaching the model how to chain 15 raw Office.js primitives, the server ships one tool call per workflow.

See the latest release · CHANGELOG.md · PLAN-workflow-surface.md.

Highlights

• Workflow tools, not primitives. excel.tabulateRegion, word.applyEdits, outlook.draftReply, powerpoint.rebuildSlideFromOutline, onenote.appendToPage, and excel.summarizeWorkbook each compress what used to be 5–20 calls into one Office.js batch (one CDP round-trip).
• Server-side query DSL. excel.query / outlook.query / powerpoint.query / onenote.query run filter / project / groupBy / agg / limit inside the host so a 100k-row workbook returns a 5-row answer.
• Persistent document context cache. *.discover tools snapshot workbook / document / mailbox / deck / notebook structure to %LOCALAPPDATA%\office-addin-mcp\doccache.json so repeat discovery calls cost zero CDP round-trips.
• MCP Resources with live subscriptions. Reference Office state by URI — office://excel/Book1/Sheet1!A1:D20, office://word//bookmark/, office://outlook/inbox, office://pp//slide, office://onenote/// — and subscribe to notifications/resources/updated when contents change.
• Macro record & replay. macro.recordstart → run any sequence of tools → macro.recordstop writes a JSON macro to disk. On next launch the server registers each macro as a callable macro. tool.
• Auto-diagnostics on Office.js errors. ItemNotFound, address parse failures, slide-index errors, and compose-vs-read mismatches are enriched in the failure envelope with availablesheets, nearestnamesuggestions, parsedaddress, slidecount, itemmode, and a recoveryHint — so the model can self-correct without a second round-trip.
• Self-healing CDP connection. If Excel closes unexpectedly, the server detects the dead connection on the next tool call, stops the stale sideload registration, relaunches Excel (including the dev server if needed), resets the session pool, and retries the original operation — no agent intervention required. Only activates when the server owns the launch (via --launch-addin or a prior addin.launch call); attaching to an external --browser-url endpoint is never disturbed.
• Progress notifications on long operations. addin.launch, addin.ensureRunning, and macro replay stream MCP $/progress notifications at each phase boundary (dev-server start, sideload, CDP-ready wait, step execution) so clients can show a live status bar instead of a silent spinner.
• Cross-host orchestration. office.embed reads a range from Excel and inserts it onto a PowerPoint slide in one call.
• Page automation fallback. page. / pages. / inspect. / interact. cover screenshot, snapshot, click, fill, type, hover, navigate, evaluate, wait, console log, network log — same primitives against headless Chrome on macOS/Linux.
• Per-host runScript escape hatch. excel.runScript, word.runScript, outlook.runScript, powerpoint.runScript, onenote.runScript run arbitrary .run callbacks when the workflow surface isn't enough.

Requirements

Shortened. The full README is on GitHub.