docs: list Plain API key permissions for support ticketing

assistant/configure.mdx

@@ -43,6 +43,14 @@
 
 Select **Direct support ticketing** to have the assistant file support requests as tickets in Plain or Zendesk instead of sending them by email.
 
+If you use Plain, create a Plain API key with these permissions before you connect:
+
+- `customer:create`
+- `customer:edit`
+- `customer:read`
+- `thread:create`
+- `thread:read`
+
 1. In the Response Handling section, select **Direct support ticketing** as the support option.
 2. Select a **Ticketing platform**: **Plain** or **Zendesk**.
 3. On the platform card, click **Connect** and follow the authorization prompts.
@@ -51,7 +59,7 @@
 
 When the assistant detects a support question, it shows the in-chat contact form. Mintlify creates a ticket in your connected platform from the submission. The ticket includes the user's contact details and message, plus up to the first three messages of the assistant conversation. If the conversation is longer, the ticket links to the full conversation in your dashboard.
 
-If the Plain API key lacks a permission that ticketing needs, the platform card shows **Scopes misconfigured**. Click **Configure** to see the missing scopes, then add them to the API key in Plain.
+If the Plain API key is missing any of the required permissions, the platform card shows **Scopes misconfigured**. Click **Configure** to see the missing scopes, then add them to the API key in Plain.
 
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