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hyunjae-labs

xlwings Excel MCP Server

by hyunjae-labs

unmerge_cells

Split merged Excel cells into individual cells to restore independent formatting and data entry. Specify the worksheet and cell range to separate previously combined cells.

Instructions

Unmerge a range of cells.

Args:
    sheet_name: Name of worksheet
    start_cell: Starting cell
    end_cell: Ending cell
    session_id: Session ID from open_workbook (preferred)
    filepath: Path to Excel file (legacy, deprecated)
    
Note: Use session_id for better performance. filepath parameter is deprecated.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
sheet_nameYes
start_cellYes
end_cellYes
session_idNo
filepathNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes

Implementation Reference

  • MCP tool handler for 'unmerge_cells'. Dispatches to session-based or legacy filepath-based unmerge implementations in range_xlw.py.
    @mcp.tool()
    def unmerge_cells(
        sheet_name: str,
        start_cell: str,
        end_cell: str,
        session_id: Optional[str] = None,
        filepath: Optional[str] = None
    ) -> str:
        """
        Unmerge a range of cells.
        
        Args:
            sheet_name: Name of worksheet
            start_cell: Starting cell
            end_cell: Ending cell
            session_id: Session ID from open_workbook (preferred)
            filepath: Path to Excel file (legacy, deprecated)
            
        Note: Use session_id for better performance. filepath parameter is deprecated.
        """
        try:
            # Support both new (session_id) and old (filepath) API
            if session_id:
                # New API: use session
                session = SESSION_MANAGER.get_session(session_id)
                if not session:
                    return ERROR_TEMPLATES['SESSION_NOT_FOUND'].format(
                        session_id=session_id, 
                        ttl=10  # Default TTL is 10 minutes (600 seconds)
                    )
                
                with session.lock:
                    from xlwings_mcp.xlwings_impl.range_xlw import unmerge_cells_xlw_with_wb
                    result = unmerge_cells_xlw_with_wb(session.workbook, sheet_name, start_cell, end_cell)
            elif filepath:
                # Legacy API: backwards compatibility
                logger.warning("Using deprecated filepath parameter. Please use session_id instead.")
                full_path = get_excel_path(filepath)
                from xlwings_mcp.xlwings_impl.range_xlw import unmerge_cells_xlw
                result = unmerge_cells_xlw(full_path, sheet_name, start_cell, end_cell)
            else:
                return ERROR_TEMPLATES['PARAMETER_MISSING'].format(
                    param1='session_id',
                    param2='filepath'
                )
            
            return result.get("message", "Cells unmerged successfully") if "error" not in result else f"Error: {result['error']}"
        except (ValidationError, SheetError) as e:
            return f"Error: {str(e)}"
        except Exception as e:
            logger.error(f"Error unmerging cells: {e}")
            raise
  • Legacy filepath-based implementation of cell unmerging using xlwings. Opens workbook, checks range, unmerges, saves and closes.
    def unmerge_cells_xlw(filepath: str, sheet_name: str, start_cell: str, end_cell: str) -> Dict[str, Any]:
        """
        Unmerge cells in Excel using xlwings.
        
        Args:
            filepath: Path to Excel file
            sheet_name: Name of worksheet
            start_cell: Top-left cell of merge range
            end_cell: Bottom-right cell of merge range
            
        Returns:
            Dict with success message or error
        """
        app = None
        wb = None
    
        # Initialize COM for thread safety (Windows)
        _com_initialize()
    
        try:
            logger.info(f"Unmerging cells {start_cell}:{end_cell} in {sheet_name}")
            
            # Check if file exists
            if not os.path.exists(filepath):
                return {"error": f"File not found: {filepath}"}
            
            # Open Excel app and workbook
            app = xw.App(visible=False, add_book=False)
            wb = app.books.open(filepath)
            
            # Check if sheet exists
            sheet_names = [s.name for s in wb.sheets]
            if sheet_name not in sheet_names:
                return {"error": f"Sheet '{sheet_name}' not found"}
            
            sheet = wb.sheets[sheet_name]
            
            # Get the range to unmerge
            unmerge_range = sheet.range(f"{start_cell}:{end_cell}")
            
            # Check if range is merged
            if not unmerge_range.merge_cells:
                return {"error": f"Range {start_cell}:{end_cell} is not merged"}
            
            # Unmerge the cells
            unmerge_range.unmerge()
            
            # Save the workbook
            wb.save()
            
            logger.info(f"✅ Successfully unmerged cells {start_cell}:{end_cell}")
            return {
                "message": f"Successfully unmerged cells {start_cell}:{end_cell}",
                "range": f"{start_cell}:{end_cell}",
                "sheet": sheet_name
            }
            
        except Exception as e:
            logger.error(f"❌ Error unmerging cells: {str(e)}")
            return {"error": str(e)}
            
        finally:
            if wb:
                wb.close()
            if app:
                app.quit()
  • Session-optimized variant of unmerge_cells that uses existing open workbook object for efficiency.
    def unmerge_cells_xlw_with_wb(wb, sheet_name: str, start_cell: str, end_cell: str) -> Dict[str, Any]:
        """
        Session-based cell unmerging using existing workbook object.
        
        Args:
            wb: Workbook object from session
            sheet_name: Name of worksheet
            start_cell: Top-left cell of merge range
            end_cell: Bottom-right cell of merge range
            
        Returns:
            Dict with success message or error
        """
        try:
            logger.info(f"🔓 Unmerging cells {start_cell}:{end_cell} in {sheet_name}")
            
            # Check if sheet exists
            sheet_names = [s.name for s in wb.sheets]
            if sheet_name not in sheet_names:
                return {"error": f"Sheet '{sheet_name}' not found"}
            
            sheet = wb.sheets[sheet_name]
            
            # Get the range to unmerge
            unmerge_range = sheet.range(f"{start_cell}:{end_cell}")
            
            # Check if range is merged
            if not unmerge_range.merge_cells:
                return {"error": f"Range {start_cell}:{end_cell} is not merged"}
            
            # Unmerge the cells
            unmerge_range.unmerge()
            
            # Save the workbook
            wb.save()
            
            logger.info(f"✅ Successfully unmerged cells {start_cell}:{end_cell}")
            return {
                "message": f"Successfully unmerged cells {start_cell}:{end_cell}",
                "range": f"{start_cell}:{end_cell}",
                "sheet": sheet_name
            }
            
        except Exception as e:
            logger.error(f"❌ Error unmerging cells: {str(e)}")
            return {"error": str(e)}
  • Higher-level wrapper around unmerge_cells_xlw in sheet.py module.
    def unmerge_range(filepath: str, sheet_name: str, start_cell: str, end_cell: str) -> Dict[str, Any]:
        """Unmerge a range of cells."""
        result = unmerge_cells_xlw(filepath, sheet_name, start_cell, end_cell)
        if "error" in result:
            raise SheetError(result["error"])
        return result

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed5 schema fields changed
    • addedInput schema / properties / filepath / anyOf
      Added value: +[
      +  {
      +    "type": "string"
      +  },
      +  {
      +    "type": "null"
      +  }
      +]
    • addedInput schema / properties / filepath / default
      Added value: +null
    • removedInput schema / properties / filepath / type
      Removed value: -"string"
    • addedInput schema / properties / session_id
      Added value: +{
      +  "anyOf": [
      +    {
      +      "type": "string"
      +    },
      +    {
      +      "type": "null"
      +    }
      +  ],
      +  "default": null,
      +  "title": "Session Id"
      +}
    • changedInput schema / required
      Previous value: -[
      -  "filepath",
      -  "sheet_name",
      -  "start_cell",
      -  "end_cell"
      -]New value: +[
      +  "sheet_name",
      +  "start_cell",
      +  "end_cell"
      +]
  2. First observed

TDQS

A3.5/5.0
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided. Description lacks details on behavioral traits such as what happens if cells are not merged, whether it modifies the workbook, or required permissions. Minimal disclosure beyond the action.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Extremely concise: one-line purpose, parameter list, and a note. No redundant text. Front-loaded with the action.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers purpose and parameter purposes, but lacks behavioral context, error conditions, or what happens on success. Output schema exists but not detailed in description. Adequate for a simple mutation tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Adds meaning beyond the schema by listing parameters with brief explanations and a note about preferring session_id. However, does not specify cell reference format (e.g., 'A1' style). Schema coverage is 0%, so description compensates well.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states 'Unmerge a range of cells', providing a specific verb and resource. It naturally distinguishes from sibling tool 'merge_cells'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool vs alternatives. Only provides parameter preference advice (session_id over filepath), not tool selection context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.