Blueprint: descriptions + descriptive errors (#43899)

homeassistant/components/automation/blueprints/motion_light.yaml

@@ -1,5 +1,6 @@
 blueprint:
   name: Motion-activated Light
+  description: Turn on a light when motion is detected.
   domain: automation
   source_url: https://github.com/home-assistant/core/blob/dev/homeassistant/components/automation/blueprints/motion_light.yaml
   input:
@@ -17,7 +18,7 @@ blueprint:
             domain: light
     no_motion_wait:
       name: Wait time
-      description: Time to wait until the light should be turned off.
+      description: Time to leave the light on after last motion is detected.
       default: 120
       selector:
         number:

homeassistant/components/automation/blueprints/notify_leaving_zone.yaml

@@ -1,5 +1,6 @@
 blueprint:
-  name: Send notification when a person leaves a zone
+  name: Zone Notification
+  description: Send a notification to a device when a person leaves a specific zone.
   domain: automation
   source_url: https://github.com/home-assistant/core/blob/dev/homeassistant/components/automation/blueprints/notify_leaving_zone.yaml
   input:
@@ -26,6 +27,7 @@ trigger:
 
 variables:
   zone_entity: !input zone_entity
+  # This is the state of the person when it's in this zone.
   zone_state: "{{ states[zone_entity].name }}"
   person_entity: !input person_entity
   person_name: "{{ states[person_entity].name }}"

homeassistant/components/blueprint/importer.py

@@ -124,7 +124,9 @@ def _extract_blueprint_from_community_topic(
         break
 
     if blueprint is None:
-        raise HomeAssistantError("No valid blueprint found in the topic")
+        raise HomeAssistantError(
+            "No valid blueprint found in the topic. Blueprint syntax blocks need to be marked as YAML or no syntax."
+        )
 
     return ImportedBlueprint(
         f'{post["username"]}/{topic["slug"]}', block_content, blueprint
@@ -204,7 +206,9 @@ async def fetch_blueprint_from_github_gist_url(
         break
 
     if blueprint is None:
-        raise HomeAssistantError("No valid blueprint found in the gist")
+        raise HomeAssistantError(
+            "No valid blueprint found in the gist. The blueprint file needs to end with '.yaml'"
+        )
 
     return ImportedBlueprint(
         f"{gist['owner']['login']}/{filename[:-5]}", content, blueprint