fix(zoho-desk): reject an empty update_ticket PATCH with a clear error

update_ticket built its PATCH body from optional fields via filterUndefined, so
a call with no fields set sent `{}` and surfaced an opaque Zoho failure. Guard
the body builder to throw an actionable "provide at least one field" error
before the request. Adds a test for the empty and populated body paths.

Author: mzxchandra

apps/sim/tools/zoho_desk/update_ticket.test.ts

@@ -0,0 +1,22 @@
+/**
+ * @vitest-environment node
+ */
+import { describe, expect, it } from 'vitest'
+import { zohoDeskUpdateTicketTool } from '@/tools/zoho_desk/update_ticket'
+
+describe('zohoDeskUpdateTicketTool request body', () => {
+  const base = { accessToken: 'tok', orgId: '700', ticketId: '123' }
+  const buildBody = zohoDeskUpdateTicketTool.request.body as (p: Record<string, unknown>) => unknown
+
+  it('throws when no updatable fields are provided', () => {
+    expect(() => buildBody(base)).toThrow(/no fields to update/i)
+  })
+
+  it('builds a body containing only the provided fields', () => {
+    expect(buildBody({ ...base, status: 'Closed' })).toEqual({ status: 'Closed' })
+    expect(buildBody({ ...base, priority: 'High', subject: 'Hi' })).toEqual({
+      priority: 'High',
+      subject: 'Hi',
+    })
+  })
+})

apps/sim/tools/zoho_desk/update_ticket.ts

@@ -101,8 +101,8 @@ export const zohoDeskUpdateTicketTool: ToolConfig<ZohoDeskUpdateTicketParams, Zo
     url: (params) => `${getZohoDeskApiBase(params)}/tickets/${encodeURIComponent(params.ticketId)}`,
     method: 'PATCH',
     headers: (params) => buildZohoDeskHeaders(params),
-    body: (params) =>
-      filterUndefined({
+    body: (params) => {
+      const body = filterUndefined({
         subject: params.subject,
         status: params.status,
         priority: params.priority,
@@ -112,7 +112,16 @@ export const zohoDeskUpdateTicketTool: ToolConfig<ZohoDeskUpdateTicketParams, Zo
         subCategory: params.subCategory,
         dueDate: params.dueDate,
         customFields: params.customFields,
-      }),
+      })
+      // Zoho rejects an empty PATCH; fail early with an actionable message
+      // instead of surfacing an opaque Zoho error for a no-op update.
+      if (Object.keys(body).length === 0) {
+        throw new Error(
+          'No fields to update. Provide at least one field to change (e.g. status, priority, or subject).'
+        )
+      }
+      return body
+    },
   },
 
   transformResponse: async (response) => {