DataBeak

Instructions

# Rename multiple columns
rename_columns(ctx, {
    "FirstName": "first_name",
    "LastName": "last_name",
    "EmailAddress": "email"
})

Implementation Reference

• src/databeak/servers/column_server.py:204-245 (handler)

  The main handler function for the 'rename_columns' tool. Validates that old column names exist in the DataFrame, renames columns using pandas df.rename(columns=mapping), updates the session DataFrame, and returns a RenameColumnsResult.

  async def rename_columns(
      ctx: Annotated[Context, Field(description="FastMCP context for session access")],
      mapping: Annotated[
          dict[str, str],
          Field(description="Dictionary mapping old column names to new names"),
      ],
  ) -> RenameColumnsResult:
      """Rename columns in the dataframe.
  
      Returns:
          Dict with rename details
  
      Examples:
          # Using dictionary mapping
          rename_columns(ctx, {"old_col1": "new_col1", "old_col2": "new_col2"})
  
          # Rename multiple columns
          rename_columns(ctx, {
              "FirstName": "first_name",
              "LastName": "last_name",
              "EmailAddress": "email"
          })
  
      """
      # Get session_id from FastMCP context
      session_id = ctx.session_id
      session, df = get_session_data(session_id)
  
      # Validate columns exist
      missing_cols = [col for col in mapping if col not in df.columns]
      if missing_cols:
          raise ColumnNotFoundError(missing_cols[0], df.columns.tolist())
  
      # Apply renaming
      session.df = df.rename(columns=mapping)
      # No longer recording operations (simplified MCP architecture)
  
      return RenameColumnsResult(
          renamed=mapping,
          columns=list(mapping.values()),
      )

• src/databeak/servers/column_server.py:115-122 (schema)

  Pydantic model defining the output schema for the rename_columns tool, including the rename mapping and final column list.

  class RenameColumnsResult(BaseToolResponse):
      """Result of renaming columns."""
  
      model_config = ConfigDict(extra="forbid")
  
      renamed: dict[str, str] = Field(description="Mapping of old names to new names")
      columns: list[str] = Field(description="List of final column names")

• src/databeak/servers/column_server.py:654-654 (registration)

  Registers the rename_columns handler function as an MCP tool named 'rename_columns' on the FastMCP column_server instance.

  column_server.tool(name="rename_columns")(rename_columns)