diff --git a/lib/context_dev/internal/util.rb b/lib/context_dev/internal/util.rb
index 1c922103..154a8a65 100644
--- a/lib/context_dev/internal/util.rb
+++ b/lib/context_dev/internal/util.rb
@@ -501,7 +501,7 @@ def writable_enum(&blk)
       # @type [Regexp]
       JSON_CONTENT = %r{^application/(?:[a-zA-Z0-9.-]+\+)?json(?!l)}
       # @type [Regexp]
-      JSONL_CONTENT = %r{^application/(:?x-(?:n|l)djson)|(:?(?:x-)?jsonl)}
+      JSONL_CONTENT = %r{^application/(?:x-(?:n|l)djson|(?:x-)?jsonl)}
 
       class << self
         # @api private
diff --git a/test/context_dev/internal/util_test.rb b/test/context_dev/internal/util_test.rb
index 1dfca4d2..af0a8d03 100644
--- a/test/context_dev/internal/util_test.rb
+++ b/test/context_dev/internal/util_test.rb
@@ -673,3 +673,28 @@ def test_decode_sse
     end
   end
 end
+
+class ContextDev::Test::UtilJsonlContentTest < Minitest::Test
+  def test_jsonl_content_type
+    matched = [
+      "application/jsonl",
+      "application/x-jsonl",
+      "application/x-ndjson",
+      "application/x-ldjson"
+    ]
+    rejected = [
+      "text/jsonl",
+      "application/octet-stream; filename=data.jsonl",
+      "random_jsonl",
+      "text/plain"
+    ]
+
+    matched.each do |content_type|
+      assert_match(ContextDev::Internal::Util::JSONL_CONTENT, content_type)
+    end
+
+    rejected.each do |content_type|
+      refute_match(ContextDev::Internal::Util::JSONL_CONTENT, content_type)
+    end
+  end
+end