diff --git a/parser/src/cfg/mod.rs b/parser/src/cfg/mod.rs
index 403303183..793cd5d58 100644
--- a/parser/src/cfg/mod.rs
+++ b/parser/src/cfg/mod.rs
@@ -825,19 +825,33 @@ fn parse_layer_indexes(exprs: &[Spanned<Vec<SExpr>>], expected_len: usize) -> Re
         if layer_indexes.get(&layer_name).is_some() {
             bail_expr!(layer_expr, "duplicate layer name: {}", layer_name);
         }
-        // Check if user tried to map parentheses by using them directly - `(` and `)`
+        // Check if user tried to use parentheses directly - `(` and `)`
         // or escaped them like in kmonad - `\(` and `\)`.
         for subexpr in subexprs {
-            if subexpr.list(None).is_some_and(|l| {
-                l.is_empty()
-                    || l.len() == 1
-                        && l.first()
-                            .is_some_and(|s| s.atom(None).is_some_and(|atom| atom == "\\"))
-            }) {
-                bail_expr!(subexpr, "If you meant to map keys to `(` and `)`, you have to use `S-0` and `S-9` instead (for US layout).\nSee https://github.com/jtroo/kanata/issues/163 for context.",)
+            if let Some(list) = subexpr.list(None) {
+                if list.is_empty() {
+                    bail_expr!(
+                        subexpr,
+                        "You can't put parentheses in deflayer directly, because they are special characters for delimiting lists.\n\
+                         To get `(` and `)` in US layout, you should use `S-9` and `S-0` respectively.\n\
+                         For more context, see: https://github.com/jtroo/kanata/issues/459"
+                    )
+                }
+                if list.len() == 1
+                    && list
+                        .first()
+                        .is_some_and(|s| s.atom(None).is_some_and(|atom| atom == "\\"))
+                {
+                    bail_expr!(
+                        subexpr,
+                        "Escaping shifted characters with `\\` is currently not supported in kanata.\n\
+                         To get `(` and `)` in US layout, you should use `S-9` and `S-0` respectively.\n\
+                         For more context, see: https://github.com/jtroo/kanata/issues/163"
+                    )
+                }
             }
         }
-        let num_actions = expr.t.len() - 1;
+        let num_actions = expr.t.len() - 2;
         if num_actions != expected_len {
             bail_span!(
                 expr,
diff --git a/parser/src/cfg/tests.rs b/parser/src/cfg/tests.rs
index fa55ac4f6..a46ed9eba 100644
--- a/parser/src/cfg/tests.rs
+++ b/parser/src/cfg/tests.rs
@@ -1249,3 +1249,55 @@ fn parse_all_defcfg() {
     )
     .expect("succeeds");
 }
+
+#[test]
+fn using_parentheses_in_deflayer_directly_fails_with_custom_message() {
+    let _lk = match CFG_PARSE_LOCK.lock() {
+        Ok(guard) => guard,
+        Err(poisoned) => poisoned.into_inner(),
+    };
+    let mut s = ParsedState::default();
+    let source = r#"
+(defsrc a b)
+(deflayer base ( ))
+"#;
+    let err = parse_cfg_raw_string(
+        source,
+        &mut s,
+        &PathBuf::from("test"),
+        &mut FileContentProvider {
+            get_file_content_fn: &mut |_| unimplemented!(),
+        },
+        DEF_LOCAL_KEYS,
+    )
+    .expect_err("should err");
+    assert!(err
+        .msg
+        .contains("You can't put parentheses in deflayer directly"));
+}
+
+#[test]
+fn using_escaped_parentheses_in_deflayer_fails_with_custom_message() {
+    let _lk = match CFG_PARSE_LOCK.lock() {
+        Ok(guard) => guard,
+        Err(poisoned) => poisoned.into_inner(),
+    };
+    let mut s = ParsedState::default();
+    let source = r#"
+(defsrc a b)
+(deflayer base \( \))
+"#;
+    let err = parse_cfg_raw_string(
+        source,
+        &mut s,
+        &PathBuf::from("test"),
+        &mut FileContentProvider {
+            get_file_content_fn: &mut |_| unimplemented!(),
+        },
+        DEF_LOCAL_KEYS,
+    )
+    .expect_err("should err");
+    assert!(err
+        .msg
+        .contains("Escaping shifted characters with `\\` is currently not supported"));
+}