diff --git a/src/style-spec/validate_mapbox_api_supported.js b/src/style-spec/validate_mapbox_api_supported.js
index 904d06f4be8..e51a99e812d 100644
--- a/src/style-spec/validate_mapbox_api_supported.js
+++ b/src/style-spec/validate_mapbox_api_supported.js
@@ -45,14 +45,14 @@ function getSourceErrors(source: Object, i: number): Array<?ValidationError> {
     errors.push(...getAllowedKeyErrors(source, sourceKeys, 'source'));
 
     /*
-     * "sprite" is optional. If present, valid examples:
+     * "source" is required. Valid examples:
      * mapbox://mapbox.abcd1234
      * mapbox://penny.abcd1234
      * mapbox://mapbox.abcd1234,penny.abcd1234
      */
     const sourceUrlPattern = /^mapbox:\/\/([^/]*)$/;
     if (!isValid(source.url, sourceUrlPattern)) {
-        errors.push(new ValidationError(`sources[${i}]`, source.url, 'Style must reference sources hosted by Mapbox'));
+        errors.push(new ValidationError(`sources[${i}]`, source.url, 'Source url must be a valid Mapbox tileset url'));
     }
 
     return errors;
@@ -105,7 +105,7 @@ function getRootErrors(style: Object, specKeys: Array<any>): Array<?ValidationEr
     errors.push(...allowedKeyErrors);
 
     if (style.version > SUPPORTED_SPEC_VERSION || style.version < SUPPORTED_SPEC_VERSION) {
-        errors.push(new ValidationError('version', style.version, `style version must be ${SUPPORTED_SPEC_VERSION}`));
+        errors.push(new ValidationError('version', style.version, `Style version must be ${SUPPORTED_SPEC_VERSION}`));
     }
 
     /*
diff --git a/test/unit/style-spec/fixture/non-mapbox-references.output-api-supported.json b/test/unit/style-spec/fixture/non-mapbox-references.output-api-supported.json
index 30dd9026f4f..051b31d31c0 100644
--- a/test/unit/style-spec/fixture/non-mapbox-references.output-api-supported.json
+++ b/test/unit/style-spec/fixture/non-mapbox-references.output-api-supported.json
@@ -8,11 +8,11 @@
     "line": 4
   },
   {
-    "message": "sources[0]: Style must reference sources hosted by Mapbox",
+    "message": "sources[0]: Source url must be a valid Mapbox tileset url",
     "line": 8
   },
   {
-    "message": "sources[1]: Style must reference sources hosted by Mapbox",
+    "message": "sources[1]: Source url must be a valid Mapbox tileset url",
     "line": 12
   }
 ]
\ No newline at end of file
diff --git a/test/unit/style-spec/fixture/root-properties.output-api-supported.json b/test/unit/style-spec/fixture/root-properties.output-api-supported.json
index 1e8a899bccb..a75dc3456ae 100644
--- a/test/unit/style-spec/fixture/root-properties.output-api-supported.json
+++ b/test/unit/style-spec/fixture/root-properties.output-api-supported.json
@@ -24,7 +24,7 @@
     "line": 3
   },
   {
-    "message": "version: style version must be 8",
+    "message": "version: Style version must be 8",
     "line": 2
   }
 ]
\ No newline at end of file
diff --git a/test/unit/style-spec/fixture/sources.output-api-supported.json b/test/unit/style-spec/fixture/sources.output-api-supported.json
index 010d8632725..7d1b02b8e87 100644
--- a/test/unit/style-spec/fixture/sources.output-api-supported.json
+++ b/test/unit/style-spec/fixture/sources.output-api-supported.json
@@ -44,7 +44,7 @@
     "line": 12
   },
   {
-    "message": "sources[2]: Style must reference sources hosted by Mapbox",
+    "message": "sources[2]: Source url must be a valid Mapbox tileset url",
     "line": 11
   },
   {
@@ -52,7 +52,7 @@
     "line": 17
   },
   {
-    "message": "sources[3]: Style must reference sources hosted by Mapbox",
+    "message": "sources[3]: Source url must be a valid Mapbox tileset url",
     "line": 16
   },
   {