diff --git a/script/lib_tests/clj_yaml_tests b/script/lib_tests/clj_yaml_tests
new file mode 100755
index 00000000..0a2ae371
--- /dev/null
+++ b/script/lib_tests/clj_yaml_tests
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+set -eo pipefail
+
+if [ "$BABASHKA_TEST_ENV" = "native" ]; then
+    BB_CMD="./bb"
+else
+    BB_CMD="lein bb"
+fi
+
+$BB_CMD -e "
+(require '[clojure.java.io :as io])
+(def test-file (io/file (System/getProperty \"java.io.tmpdir\") \"core_test.clj\"))
+(io/copy
+  (io/input-stream \"https://raw.githubusercontent.com/clj-commons/clj-yaml/master/test/clj_yaml/core_test.clj\")
+  test-file)
+(load-file test-file)
+(require '[clojure.test :as t])
+(let [{:keys [:test :pass :fail :error]} (t/run-tests 'clj-yaml.core-test)]
+  (when-not (pos? test)
+    (System/exit 1))
+  (System/exit (+ fail error)))
+"
diff --git a/script/run_lib_tests b/script/run_lib_tests
index 3130036b..49ac84db 100755
--- a/script/run_lib_tests
+++ b/script/run_lib_tests
@@ -12,3 +12,4 @@ script/lib_tests/babashka_curl_test
 script/lib_tests/cprop_test
 script/lib_tests/comb_test
 script/lib_tests/arrangement_test
+script/lib_tests/clj_yaml_test
diff --git a/src/babashka/impl/classes.clj b/src/babashka/impl/classes.clj
index 21a74071..57707e8a 100644
--- a/src/babashka/impl/classes.clj
+++ b/src/babashka/impl/classes.clj
@@ -112,7 +112,9 @@
           java.util.zip.InflaterInputStream
           java.util.zip.DeflaterInputStream
           java.util.zip.GZIPInputStream
-          java.util.zip.GZIPOutputStream]
+          java.util.zip.GZIPOutputStream
+          org.yaml.snakeyaml.error.YAMLException
+          ]
     :constructors [clojure.lang.Delay
                    clojure.lang.MapEntry
                    clojure.lang.LineNumberingPushbackReader
diff --git a/src/babashka/impl/yaml.clj b/src/babashka/impl/yaml.clj
index 1c1206c0..33ad7a4f 100644
--- a/src/babashka/impl/yaml.clj
+++ b/src/babashka/impl/yaml.clj
@@ -7,5 +7,7 @@
 (def yns (vars/->SciNamespace 'clj-yaml.core nil))
 
 (def yaml-namespace
-  {'generate-string (copy-var yaml/generate-string yns)
+  {'mark (copy-var yaml/mark yns)
+   'unmark (copy-var yaml/unmark yns)
+   'generate-string (copy-var yaml/generate-string yns)
    'parse-string (copy-var yaml/parse-string yns)})