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xlwings Excel MCP Server

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
Behavior2/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. While it mentions the tool's action (unmerging cells) and performance considerations, it doesn't address important behavioral aspects like: whether this operation is destructive (likely yes, but not stated), what happens to data in previously merged cells, error conditions, or authentication requirements. The description provides basic operational context but misses key behavioral traits.

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?

The description is perfectly structured and front-loaded: a clear purpose statement followed by organized parameter documentation with practical notes. Every sentence earns its place - the first states the action, the Args section documents parameters efficiently, and the Note provides crucial usage guidance without redundancy.

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?

Given this is a mutation tool with no annotations but with an output schema, the description provides adequate operational context but could be more complete. It covers the basic action and parameters well, but lacks information about the mutation's effects, error handling, and relationship to sibling tools. The presence of an output schema means return values are documented elsewhere, but behavioral aspects remain under-specified.

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?

With 0% schema description coverage, the description compensates well by explaining all 5 parameters in the 'Args' section, including their purposes and usage guidance (session_id preferred, filepath deprecated). It adds meaningful context beyond the bare parameter names in the schema, though it could provide more detail about cell range formatting or sheet name constraints.

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?

The description clearly states the specific action ('unmerge') and target resource ('a range of cells'), distinguishing it from sibling tools like 'merge_cells' (which does the opposite) and other Excel manipulation tools. It provides a precise verb+resource combination that leaves no ambiguity about the tool's function.

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

Usage Guidelines4/5

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

The description provides clear context about parameter usage (preferring session_id over deprecated filepath for better performance), but doesn't explicitly state when to use this tool versus alternatives like 'merge_cells' or other cell manipulation tools. It offers practical guidance on parameter selection but lacks sibling tool differentiation.

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

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