diff --git a/cirq-core/cirq/__init__.py b/cirq-core/cirq/__init__.py
index 21fd3885910..2e5d1a9d96f 100644
--- a/cirq-core/cirq/__init__.py
+++ b/cirq-core/cirq/__init__.py
@@ -541,6 +541,7 @@
     SupportsExplicitQidShape,
     SupportsExplicitNumQubits,
     SupportsJSON,
+    SupportsKraus,
     SupportsMeasurementKey,
     SupportsMixture,
     SupportsParameterization,
diff --git a/cirq-core/cirq/protocols/json_test_data/spec.py b/cirq-core/cirq/protocols/json_test_data/spec.py
index e15ee68cb6a..ce01b7b6766 100644
--- a/cirq-core/cirq/protocols/json_test_data/spec.py
+++ b/cirq-core/cirq/protocols/json_test_data/spec.py
@@ -143,6 +143,7 @@
         'SupportsExplicitNumQubits',
         'SupportsExplicitQidShape',
         'SupportsJSON',
+        'SupportsKraus',
         'SupportsMeasurementKey',
         'SupportsMixture',
         'SupportsParameterization',