Add external_references to conversation schema (Preview)

Documents the external_references array on the conversation and
conversation_list_item schemas for the Preview API.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: hrp

descriptions/0/api.intercom.io.yaml

@@ -29214,6 +29214,16 @@ components:
           type: object
           nullable: true
           description: The channel through which the conversation was initiated and its current channel.
+        external_references:
+          type: array
+          description: References linking this conversation to records in an external helpdesk or CRM system. Populated for Fin Standalone workspaces synced from an external platform; an empty array otherwise. Sorted alphabetically by `type` and capped at 20 entries.
+          items:
+            "$ref": "#/components/schemas/conversation_external_reference"
+          example:
+            - type: zendesk_ticket
+              id: '3633338'
+            - type: zendesk_sunshine_conversation
+              id: abc-def-uuid
         monitor_evaluations:
           type: array
           description: QA monitor evaluations that flagged this conversation. Only included when `include_monitors=true` is passed as a query parameter.
@@ -29357,6 +29367,16 @@ components:
           type: object
           nullable: true
           description: The channel through which the conversation was initiated and its current channel.
+        external_references:
+          type: array
+          description: References linking this conversation to records in an external helpdesk or CRM system. Populated for Fin Standalone workspaces synced from an external platform; an empty array otherwise. Sorted alphabetically by `type` and capped at 20 entries.
+          items:
+            "$ref": "#/components/schemas/conversation_external_reference"
+          example:
+            - type: zendesk_ticket
+              id: '3633338'
+            - type: zendesk_sunshine_conversation
+              id: abc-def-uuid
         monitor_evaluations:
           type: array
           description: QA monitor evaluations that flagged this conversation. Only included when `include_monitors=true` is passed as a query parameter.
@@ -29540,6 +29560,29 @@ components:
           nullable: true
           description: The current channel of the conversation. May differ from `initial` if the conversation was migrated between channels. Returns `null` if channel data is unavailable.
           example: messenger
+    conversation_external_reference:
+      title: Conversation External Reference
+      type: object
+      description: A reference linking a conversation to a record in an external helpdesk or CRM system, surfaced for Fin Standalone workspaces.
+      properties:
+        type:
+          type: string
+          description: The type of external system the reference points to.
+          enum:
+            - zendesk_ticket
+            - zendesk_sunshine_conversation
+            - salesforce_case
+            - salesforce_in_app_message_conversation
+            - freshdesk_ticket
+            - freshchat_conversation
+            - hubspot_conversation
+            - custom_helpdesk_conversation
+            - api_conversation
+          example: zendesk_ticket
+        id:
+          type: string
+          description: The identifier of the record in the external system. Always serialized as a string, since some external IDs exceed 32-bit integer range.
+          example: '3633338'
     conversation_attachment_files:
       title: Conversation attachment files
       type: object