diff --git a/packages/core/platform/sources/mongodb-application.yaml b/packages/core/platform/sources/mongodb-application.yaml
index 67f7f25c6..8b30e2f29 100644
--- a/packages/core/platform/sources/mongodb-application.yaml
+++ b/packages/core/platform/sources/mongodb-application.yaml
@@ -15,6 +15,15 @@ spec:
         - cozystack.networking
         # cozystack-engine ships the ApplicationDefinition CRD rendered by the *-rd component below.
         - cozystack.cozystack-engine
+        # The mongodb chart renders kind: PerconaServerMongoDB from
+        # psmdb.percona.com/v1, so the operator that serves that CRD is a
+        # prerequisite of offering the app at all. Without this edge the
+        # mongodb-rd HelmRelease registers the ApplicationDefinition as soon as
+        # the engine is up, a tenant can create a MongoDB before the operator
+        # exists, and its HelmRelease fails with `no matches for kind
+        # "PerconaServerMongoDB"`. Same shape as every other operator-backed app
+        # here (postgres, mariadb, kafka, redis, etcd).
+        - cozystack.mongodb-operator
       libraries:
         - name: cozy-lib
           path: library/cozy-lib
diff --git a/packages/core/platform/tests/sources_mongodb_application_dependson_test.yaml b/packages/core/platform/tests/sources_mongodb_application_dependson_test.yaml
new file mode 100644
index 000000000..4cbbe0247
--- /dev/null
+++ b/packages/core/platform/tests/sources_mongodb_application_dependson_test.yaml
@@ -0,0 +1,31 @@
+suite: mongodb-application waits for the operator that serves its CRD
+# The mongodb chart (apps/mongodb) renders kind: PerconaServerMongoDB from
+# psmdb.percona.com/v1, so cozystack.mongodb-operator is a genuine prerequisite
+# of offering the app rather than a test-selection hint. Without this edge the
+# mongodb-rd HelmRelease registers the ApplicationDefinition as soon as
+# cozystack-engine is up, a tenant can create a MongoDB before the operator
+# exists, and its HelmRelease fails with `no matches for kind
+# "PerconaServerMongoDB"`.
+# The edge is also what makes the mongodb Chainsaw suite reachable from the
+# operator's own package, so a change to the operator selects that suite instead
+# of the whole run — see hack/select-e2e.sh's src_to_suites().
+templates:
+  - templates/sources.yaml
+release:
+  name: cozystack
+  namespace: cozy-system
+tests:
+  - it: mongodb-application dependsOn mongodb-operator alongside its baseline edges
+    documentSelector:
+      path: metadata.name
+      value: cozystack.mongodb-application
+    asserts:
+      - contains:
+          path: spec.variants[0].dependsOn
+          content: cozystack.mongodb-operator
+      - contains:
+          path: spec.variants[0].dependsOn
+          content: cozystack.networking
+      - contains:
+          path: spec.variants[0].dependsOn
+          content: cozystack.cozystack-engine