diff --git a/app/swagger.yml b/app/swagger.yml
index cdbbb2a..3d1c372 100644
--- a/app/swagger.yml
+++ b/app/swagger.yml
@@ -137,6 +137,9 @@ paths:
                     This is the actual reading taken from the specified
                     light meter, at the time specified in this response
                     body (I.E. JSON object).
+        400:
+          description: >-
+            The light-meter Id. specified in invalid.
 
   /readings/all/{light_meter}:
     get:
@@ -188,6 +191,9 @@ paths:
                     This is the actual reading taken from the specified
                     light meter, at the time specified in this response
                     body (I.E. JSON object).
+        400:
+          description: >-
+            The light-meter Id. specified in invalid.
 
   /readings/all:
     get:
@@ -326,6 +332,9 @@ paths:
                 type: string
                 example: on
                 description: The current status of the device.
+        400:
+          description: >-
+            The device Id. specified in invalid.
 
   /status/all/{device}:
     get:
@@ -376,6 +385,9 @@ paths:
                 example: off
                 description: >-
                   The status of the device after the change occurred.
+        400:
+          description: >-
+            The device Id. specified in invalid.
 
   /status/all:
     get: