diff --git a/ipn/ipnlocal/local.go b/ipn/ipnlocal/local.go
index 048bb1219..55730489e 100644
--- a/ipn/ipnlocal/local.go
+++ b/ipn/ipnlocal/local.go
@@ -2071,6 +2071,14 @@ func mutationsAreWorthyOfTellingIPNBus(muts []netmap.NodeMutation) bool {
 //
 // b.mu must be held.
 func (b *LocalBackend) resolveAutoExitNodeLocked(prefs *ipn.Prefs) (prefsChanged bool) {
+	// As of 2025-07-08, the only supported auto exit node expression is [ipn.AnyExitNode].
+	//
+	// However, to maintain forward compatibility with future auto exit node expressions,
+	// we treat any non-empty AutoExitNode as [ipn.AnyExitNode].
+	//
+	// If and when we support additional auto exit node expressions, this method should be updated
+	// to handle them appropriately, while still falling back to [ipn.AnyExitNode] or a more appropriate
+	// default for unknown (or partially supported) expressions.
 	if !prefs.AutoExitNode.IsSet() {
 		return false
 	}
diff --git a/ipn/ipnlocal/local_test.go b/ipn/ipnlocal/local_test.go
index 73bae7ede..e70e5ad2a 100644
--- a/ipn/ipnlocal/local_test.go
+++ b/ipn/ipnlocal/local_test.go
@@ -1002,6 +1002,23 @@ func TestConfigureExitNode(t *testing.T) {
 				AutoExitNode: "foo",
 			},
 		},
+		{
+			name: "auto-foo-via-edit-prefs", // set auto exit node via EditPrefs with an unknown/unsupported expression
+			prefs: ipn.Prefs{
+				ControlURL: controlURL,
+			},
+			netMap: clientNetmap,
+			report: report,
+			changePrefs: &ipn.MaskedPrefs{
+				Prefs:           ipn.Prefs{AutoExitNode: "foo"},
+				AutoExitNodeSet: true,
+			},
+			wantPrefs: ipn.Prefs{
+				ControlURL:   controlURL,
+				ExitNodeID:   exitNode1.StableID(), // unknown exit node expressions should work as "any"
+				AutoExitNode: "foo",
+			},
+		},
 		{
 			name: "auto-any-via-policy/toggle-off", // cannot toggle off the exit node if it was set via syspolicy
 			prefs: ipn.Prefs{