diff --git a/pkg/connector/provider/registry.go b/pkg/connector/provider/registry.go
index bd2b3ea09..925453e37 100644
--- a/pkg/connector/provider/registry.go
+++ b/pkg/connector/provider/registry.go
@@ -120,6 +120,14 @@ func (r *Registry) Register(reg *Registration) error {
 		return fmt.Errorf("cannot register connector provider %q: ManagedAPIKey is mutually exclusive with SupportsAPIKey and SupportsClientCredentials", reg.Provider)
 	}
 
+	// RequiresManagedResourceID only has meaning for a ManagedAPIKey provider:
+	// ManagedConnectorReady consults it exclusively on that path, so setting it
+	// on a non-managed provider is a silently ineffective flag. Reject it at
+	// startup rather than let the requirement quietly do nothing.
+	if reg.RequiresManagedResourceID && !reg.ManagedAPIKey {
+		return fmt.Errorf("cannot register connector provider %q: RequiresManagedResourceID requires ManagedAPIKey", reg.Provider)
+	}
+
 	// BuildTokenURLForDomain and BuildTokenURLForSite both build the token
 	// endpoint host, but from different sources (a callback param vs. the
 	// signed state). CompleteWithState checks them in order, so setting both
diff --git a/pkg/connector/provider/registry_test.go b/pkg/connector/provider/registry_test.go
index 2e30e184a..3725a182b 100644
--- a/pkg/connector/provider/registry_test.go
+++ b/pkg/connector/provider/registry_test.go
@@ -138,6 +138,19 @@ func TestRegistry_Register(t *testing.T) {
 		assert.Contains(t, err.Error(), "mutually exclusive")
 	})
 
+	t.Run("RequiresManagedResourceID requires ManagedAPIKey", func(t *testing.T) {
+		t.Parallel()
+
+		r := provider.NewRegistry()
+		err := r.Register(&provider.Registration{
+			Provider:                  coredata.ConnectorProviderSlack,
+			DisplayName:               "Slack",
+			RequiresManagedResourceID: true,
+		})
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "RequiresManagedResourceID requires ManagedAPIKey")
+	})
+
 	t.Run("duplicate registration", func(t *testing.T) {
 		t.Parallel()