Document AU timesheet line creation best practice in tool descriptions

For AU payroll, timesheets should be created empty then lines added
individually via add-timesheet-line. Passing lines at creation time
creates separate rows per day in the Xero UI instead of consolidating
them by earnings rate.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: elliotchisholm

src/tools/create/create-payroll-timesheet.tool.ts

@@ -9,7 +9,8 @@ import { CreateXeroTool } from "../../helpers/create-xero-tool.js";
 const CreatePayrollTimesheetTool = CreateXeroTool(
   "create-timesheet",
   `Create a new payroll timesheet in Xero.
-Supports AU, NZ, and UK payroll regions. The organisation's region is auto-detected.`,
+Supports AU, NZ, and UK payroll regions. The organisation's region is auto-detected.
+IMPORTANT: For AU payroll, create the timesheet WITHOUT timesheetLines, then use add-timesheet-line to add lines one at a time. Passing lines at creation time creates separate rows per day in the UI instead of consolidating them by earnings rate.`,
   {
     payrollCalendarID: z.string().describe("The ID of the payroll calendar."),
     employeeID: z.string().describe("The ID of the employee."),

src/tools/update/update-payroll-timesheet-add-line.tool.ts

@@ -9,7 +9,8 @@ import { CreateXeroTool } from "../../helpers/create-xero-tool.js";
 const AddTimesheetLineTool = CreateXeroTool(
   "add-timesheet-line",
   `Add a new timesheet line to an existing payroll timesheet in Xero.
-Supports AU, NZ, and UK payroll regions. The organisation's region is auto-detected.`,
+Supports AU, NZ, and UK payroll regions. The organisation's region is auto-detected.
+For AU payroll, this is the recommended way to add hours. Lines added this way with the same earnings rate are consolidated into a single row in the UI. Add one line per day per earnings rate.`,
   {
     timesheetID: z.string().describe("The ID of the timesheet to update."),
     timesheetLine: z.object({