diff --git a/src/abstract_tree/tool.rs b/src/abstract_tree/tool.rs
index 5c5f983..8f6d91e 100644
--- a/src/abstract_tree/tool.rs
+++ b/src/abstract_tree/tool.rs
@@ -14,6 +14,8 @@ pub enum Tool {
     Read,
     Help,
 
+    Length,
+
     Raw,
     Sh,
     Bash,
@@ -38,6 +40,8 @@ impl Tool {
             "assert_equal" => Tool::AssertEqual,
             "output" => Tool::Output,
 
+            "length" => Tool::Length,
+
             "raw" => Tool::Raw,
             "sh" => Tool::Sh,
             "bash" => Tool::Bash,
@@ -118,6 +122,29 @@ impl Tool {
 
                 Value::Empty
             }
+            Tool::Length => {
+                if values.len() != 1 {
+                    return Err(Error::ExpectedToolArgumentAmount {
+                        tool_name: "len",
+                        expected: 1,
+                        actual: values.len(),
+                    });
+                }
+
+                let length = if let Ok(list) = values[0].as_list() {
+                    list.len()
+                } else if let Ok(map) = values[0].as_map() {
+                    map.len()
+                } else if let Ok(table) = values[0].as_table() {
+                    table.len()
+                } else if let Ok(string) = values[0].as_string() {
+                    string.chars().count()
+                } else {
+                    1
+                };
+
+                Value::Integer(length as i64)
+            }
             Tool::Read => {
                 if values.len() != 1 {
                     return Err(Error::ExpectedToolArgumentAmount {
diff --git a/tree-sitter-dust b/tree-sitter-dust
index cf22950..9ec43a9 160000
--- a/tree-sitter-dust
+++ b/tree-sitter-dust
@@ -1 +1 @@
-Subproject commit cf22950b7ee6f40c7840b6af4d7b2dda69f4965b
+Subproject commit 9ec43a98418f395a668c59a79b0832e563d9f0e4