diff --git a/spec/components/commons/query.yaml b/spec/components/commons/query.yaml
index c0f8513..4b78ca3 100644
--- a/spec/components/commons/query.yaml
+++ b/spec/components/commons/query.yaml
@@ -226,7 +226,7 @@ components:
           $ref: "#/components/schemas/PriceField"
         type: array
     q:
-      description: "Mutually exclusive with 'coordinates' parameter! Query string, can be location name or IATA code. For IATA the query parameter looks like this: 'q=iata:jfk'"
+      description: "Mutually exclusive with 'coordinates' parameter! Query string, can be location name or IATA code. For IATA the query parameter looks like this: 'q=iata:jfk'. Must contain at least one letter or number and must not exceed 150 characters; special characters are ignored. Queries not meeting these rules are rejected with a 400 response."
       examples:
         search_by_IATA:
           summary: Search by IATA airport codes.
diff --git a/spec/paths/tours.yaml b/spec/paths/tours.yaml
index 32aab4b..c870002 100644
--- a/spec/paths/tours.yaml
+++ b/spec/paths/tours.yaml
@@ -45,7 +45,7 @@ paths:
                         items:
                           $ref: "../components/schema/tour.yaml#/components/schemas/Tour"
         400:
-          description: Missing Parameters
+          description: Missing or invalid parameters, e.g. a 'q' value that contains no letters or numbers or exceeds 150 characters.
         500:
           description: Server error