CSV MCP Server

Instructions

Update a specific cell in the CSV file.

Args:
    filename: Name of the CSV file to update
    row_index: Zero-based index of the row to update
    column: Name of the column to update
    value: New value for the cell

Returns:
    Dictionary with update results

Implementation Reference

• csv_mcp_server/server.py:85-107 (handler)

  MCP tool handler for 'update_csv'. Registers the tool and delegates execution to CSVManager.update_csv, with error handling. The function signature defines the input schema.

  @mcp.tool()
  def update_csv(
      filename: str,
      row_index: int,
      column: str,
      value: Any
  ) -> Dict[str, Any]:
      """
      Update a specific cell in the CSV file.
      
      Args:
          filename: Name of the CSV file to update
          row_index: Zero-based index of the row to update
          column: Name of the column to update
          value: New value for the cell
      
      Returns:
          Dictionary with update results
      """
      try:
          return csv_manager.update_csv(filename, row_index, column, value)
      except Exception as e:
          return {"success": False, "error": str(e)}

• csv_mcp_server/csv_manager.py:189-226 (helper)

  Core implementation of CSV update logic in CSVManager class. Handles file path resolution, backup creation, pandas DataFrame loading, cell update, saving, validation, and returns detailed results.

  def update_csv(self, filename: str, row_index: int, column: str, value: Any) -> Dict[str, Any]:
      """Update a specific cell in the CSV file."""
      filepath = self._get_file_path(filename)
      
      if not filepath.exists():
          raise FileNotFoundError(f"CSV file '{filename}' not found")
      
      # Create backup
      self._create_backup(filepath)
      
      try:
          df = pd.read_csv(filepath)
          
          if row_index >= len(df):
              raise IndexError(f"Row index {row_index} out of range (max: {len(df)-1})")
          
          if column not in df.columns:
              raise ValueError(f"Column '{column}' not found in CSV")
          
          old_value = df.loc[row_index, column]
          df.loc[row_index, column] = value
          
          df.to_csv(filepath, index=False)
          self._validate_file_size(filepath)
          
          logger.info(f"Updated CSV file: {filepath}")
          return {
              "success": True,
              "filename": filename,
              "row_index": row_index,
              "column": column,
              "old_value": old_value,
              "new_value": value
          }
      except Exception as e:
          logger.error(f"Failed to update CSV: {e}")
          raise

• csv_mcp_server/server.py:85-85 (registration)

  The @mcp.tool() decorator registers the update_csv function as an MCP tool.

  @mcp.tool()