diff --git a/Chart.yaml b/Chart.yaml
index 6d1e882..0c4fbfd 100644
--- a/Chart.yaml
+++ b/Chart.yaml
@@ -1,4 +1,4 @@
 apiVersion: v1
 name: pgdog
-version: v0.70
+version: v0.71
 appVersion: "0.1.47"
diff --git a/templates/config.yaml b/templates/config.yaml
index e1d9579..8b7c13a 100644
--- a/templates/config.yaml
+++ b/templates/config.yaml
@@ -357,9 +357,7 @@ data:
         [[query_parsers]]
         database = {{ .database | quote }}
         level = {{ .level | quote }}
-        {{- if hasKey . "engine" }}
-        engine = {{ .engine | quote }}
-        {{- end }}
+        engine = {{ .engine | default "pg_query_protobuf" | quote }}
         {{- end }}
 
         {{- range .Values.shardedSchemas }}
diff --git a/test/values-pgdog-config-extras.yaml b/test/values-pgdog-config-extras.yaml
index 5c9169c..7fe057f 100644
--- a/test/values-pgdog-config-extras.yaml
+++ b/test/values-pgdog-config-extras.yaml
@@ -67,3 +67,6 @@ queryParsers:
   - database: primary
     level: "off"
     engine: pg_query_raw
+  # engine omitted: should render the pg_query_protobuf default
+  - database: primary_mirror
+    level: "session_control_and_locks"
diff --git a/values.yaml b/values.yaml
index 8191d35..95345a4 100644
--- a/values.yaml
+++ b/values.yaml
@@ -228,7 +228,9 @@ users: []
 mirrors: []
 
 # queryParsers contains per-database query parser settings in pgdog.toml.
-# Each entry requires: database and level; engine is optional.
+# Each entry requires: database and level; engine is optional and
+# defaults to "pg_query_protobuf" (pgdog requires the field in
+# [[query_parsers]] entries and fails to start without it).
 # Example:
 # queryParsers:
 #   - database: "prod"