Add LinearB AI review and description automations (#821)

Author: vim-zz

docs/downloads/gitstream-bb.cm

@@ -6,6 +6,26 @@ manifest:
 
 
 automations:
+  # Use LinearB's AI service to review the changes
+  linearb_ai_review:
+    if:
+      - {{ not pr.draft }}
+      - {{ not is.bot }}
+    run:
+      - action: code-review@v1
+        args:
+          approve_on_LGTM: {{ calc.safe_changes }}
+
+  # Use LinearB's AI service to add a description to the PR
+  linearb_ai_description:
+    if:
+      - {{ not pr.draft }}
+      - {{ not (is.bot_author or is.bot_branch) }}
+    run:
+      - action: describe-changes@v1
+        args:
+          concat_mode: append
+
   # Add a label indicating how long it will take to review the PR.
   estimated_time_to_review:
     if: