diff --git a/docs/spec.yaml b/docs/spec.yaml
index 8e6094c..0f9347d 100644
--- a/docs/spec.yaml
+++ b/docs/spec.yaml
@@ -105,12 +105,12 @@ resources:
               max_length: 100
           - name: "taxabilityCode"
             type: "string"
-            format: "date"
+            format: "number"
             required: false
             location: "query"
-            description: "Historical date for rates (YYYY-MM format)"
+            description: "Taxability Code (product or service code)"
             validation:
-              pattern: "^[0-9]{4}-[0-9]{2}$"
+              pattern: "^[0-9]+$"
           - name: "countryCode"
             type: "string"
             required: false