CSV Editor

Instructions

Implementation Reference

• src/csv_editor/tools/transformations.py:634-690 (handler)

  Core handler function that executes the duplicate removal using pandas.DataFrame.drop_duplicates, updates the session dataframe, records the operation, and returns statistics on rows removed.

  async def remove_duplicates(
      session_id: str,
      subset: Optional[List[str]] = None,
      keep: str = "first",
      ctx: Context = None
  ) -> Dict[str, Any]:
      """
      Remove duplicate rows.
      
      Args:
          session_id: Session identifier
          subset: Column names to consider for duplicates (None for all)
          keep: Which duplicates to keep ('first', 'last', False to drop all)
          ctx: FastMCP context
          
      Returns:
          Dict with success status and duplicate info
      """
      try:
          manager = get_session_manager()
          session = manager.get_session(session_id)
          
          if not session or session.df is None:
              return {"success": False, "error": "Invalid session or no data loaded"}
          
          df = session.df
          rows_before = len(df)
          
          if subset:
              missing_cols = [col for col in subset if col not in df.columns]
              if missing_cols:
                  return {"success": False, "error": f"Columns not found: {missing_cols}"}
          
          # Convert keep parameter
          keep_param = keep if keep != "none" else False
          
          session.df = df.drop_duplicates(subset=subset, keep=keep_param).reset_index(drop=True)
          rows_after = len(session.df)
          
          session.record_operation(OperationType.REMOVE_DUPLICATES, {
              "subset": subset,
              "keep": keep,
              "rows_removed": rows_before - rows_after
          })
          
          return {
              "success": True,
              "rows_before": rows_before,
              "rows_after": rows_after,
              "duplicates_removed": rows_before - rows_after,
              "subset": subset,
              "keep": keep
          }
          
      except Exception as e:
          logger.error(f"Error removing duplicates: {str(e)}")
          return {"success": False, "error": str(e)}

• src/csv_editor/server.py:280-288 (registration)

  MCP tool registration decorator and wrapper function that delegates to the core implementation in transformations.py, defining the tool schema via type annotations.

  @mcp.tool
  async def remove_duplicates(
      session_id: str,
      subset: Optional[List[str]] = None,
      keep: str = "first",
      ctx: Context = None
  ) -> Dict[str, Any]:
      """Remove duplicate rows."""
      return await _remove_duplicates(session_id, subset, keep, ctx)

• src/csv_editor/models/data_models.py:38-38 (helper)

  OperationType enum value used to record the remove_duplicates operation in session history.

  REMOVE_DUPLICATES = "remove_duplicates"