Excel MCP Server skill for Windows workbook automation. Use when an assistant needs rich MCP tools to create, inspect, modify, format, or analyze Excel files. Supports Power Query (M), Data Model/DAX, PivotTables, Tables, Ranges, Charts, Slicers, formatting, screenshots, VBA macros, connections, and

Excel MCP Server Skill Provides 326 Excel operations via Model Context Protocol. The MCP Server hosts the ExcelMCP Service in process and calls it directly for low latency Excel automation. Tools are auto discovered this documents quirks, workflows, and gotchas. Workflow Checklist Step Tool Action When 1. Open file file open or create Always first 2. Create sheets worksheet create , rename If needed 3. Write data range set values Always (2D arrays) 4. Format range set number format After writing 5. Structure table create Convert data to tables 6. Save & close file close with save: true Always last Preconditions Windows host with Microsoft Excel installed (2016+) Use full Windows paths: C:\Users\Name\Documents\Report.xlsx Excel files must not be open in another Excel instance Calculation Mode Workflow (Batch Performance) Use calculation mode for bulk write performance optimization . When writing many values or formulas, disable auto recalc to avoid recalculating after every cell: Note: You do NOT need manual mode to read formulas range get formulas returns formula text regardless of calculation mode. CRITICAL: Execution Rules (MUST FOLLOW) Rule 1: NEVER Ask Clarifying Questions STOP. If you're about to ask "Which file?", "What table?", "Where should I put this?" DON'T. Bad (Asking) Good (Discovering) "Which Excel file should I use?" file(list) → use the open session "What's the table name?" table(list) → discover tables "Which sheet has the data?" worksheet(list) → check all sheets "Should I create a PivotTable?" YES create it on a new sheet You have tools to answer your own questions. USE THEM. Rule 2: Always End With a Text Summary NEVER end your turn with only a tool call. After completing all operations, always provide a brief text message confirming what was done. Silent tool call only responses are incomplete. Rule 3: Format Data Professionally Always apply number formats after setting values: Data Type Format Code Result USD $ , 0.00 $1,234.56 EUR € , 0.00 €1,234.56 Percent 0.00% 15.00% Date (ISO) yyyy mm dd 2025 01 22 Write format codes in US notation ( , grouping, . decimal) regardless of the machine's locale — Excel translates them. The rendered separators follow the user's Windows regional settings, so $ , 0.00 shows $1.234,56 on a German system. Don't "fix" that by swapping the separators in the format code; it would break on every other locale. Workflow: Step 3 is not optional. A column sized for 45678 is too narrow once that value renders as 2025 01 22 or $1,234.56 , and Excel displays instead of the number. Rule 4: Use Excel Tables (Not Plain Ranges) Always convert tabular data to Excel Tables: Why: Structured references, auto expand, required for Data Model/DAX. Rule 5: Session Lifecycle Pass that same value as session id on every session based follow up call. sessionId above is a local variable, not an MCP argument name. When reusing a session from file(list) , copy the matching entry's sessionId value into session id . Never guess or substitute a session. Unclosed sessions leave Excel processes running, locking files. Rule 6: Data Model Prerequisites DAX operations require tables in the Data Model: Rule 7: Power Query Development Lifecycle BEST PRACTICE: Test First Workflow Why evaluate first: Catches syntax errors and missing sources BEFORE creating permanent queries Better error messages than COM exceptions from create/update See actual data preview (columns + sample rows) No cleanup needed like a REPL for M code Skip only for trivial literal tables Common mistake: Creating/updating without evaluate → pollutes workbook with broken queries Rule 8: Targeted Updates Over Delete Rebuild Prefer : set values on specific range (e.g., A5:C5 for row 5) Avoid : Deleting and recreating entire structures Why: Preserves formatting, formulas, and references. Rule 9: Follow suggestedNextActions Error responses include actionable hints: Tool Selection Quick Reference Task Tool Key Action Create/open/save workbooks file open, create, close Write/read cell data range set values, get values Format cells range set number format Create tables from data table create Add table to Power Pivot table add to data model Create DAX formulas datamodel create measure Create PivotTables pivottable create, create from datamodel Filter with slicers slicer set slicer selection Create charts chart create from range Run what if analysis analysis goal seek, create scenario, create data table Control calculation mode calculation mode get mode, set mode, calculate Visual verification screenshot capture, capture sheet Reference Documentation See references/ for detailed guidance: [What if analysis and Solver limits](./references/analysis.md) [Core execution rules and LLM guidelines](./references/behavioral rules.md) [Common mistakes to avoid](./references/anti patterns.md) [Bulk write performance optimization](./references/calculation.md) [Data Model constraints and patterns](./references/workflows.md) [Charts and formatting](./references/chart.md) [Conditional formatting operations](./references/conditionalformat.md) [Dashboard and report best practices](./references/dashboard.md) [Data Model/DAX specifics](./references/datamodel.md) [DMV query reference for Data Model analysis](./references/dmv reference.md) [Excel agent mode and advanced automation](./references/excel agent mode.md) [Gotchas and known limits](./references/gotchas.md) [Power Query M code syntax reference](./references/m code syntax.md) [PivotTable operations](./references/pivottable.md) [Power Query specifics](./references/powerquery.md) [Range operations and number formats](./references/range.md) [Screenshot and visual verification](./references/screenshot.md) [Slicer operations](./references/slicer.md) [Table operations](./references/table.md) [Window and visibility operations](./references/window.md) [Worksheet operations](./references/worksheet.md)

excel-mcp