diff --git a/src/built_in_functions/assert.rs b/src/built_in_functions/assert.rs
index 77ee769..e3f3b64 100644
--- a/src/built_in_functions/assert.rs
+++ b/src/built_in_functions/assert.rs
@@ -1,4 +1,4 @@
-use crate::{BuiltInFunction, Error, Result, Value};
+use crate::{BuiltInFunction, Error, Map, Result, Value};
 
 pub struct Assert;
 
@@ -7,7 +7,7 @@ impl BuiltInFunction for Assert {
         "assert"
     }
 
-    fn run(&self, arguments: &[Value]) -> Result<Value> {
+    fn run(&self, arguments: &[Value], _context: &Map) -> Result<Value> {
         for argument in arguments {
             if !argument.as_boolean()? {
                 return Err(Error::AssertFailed);
@@ -17,3 +17,27 @@ impl BuiltInFunction for Assert {
         Ok(Value::Empty)
     }
 }
+
+pub struct AssertEqual;
+
+impl BuiltInFunction for AssertEqual {
+    fn name(&self) -> &'static str {
+        "assert_equal"
+    }
+
+    fn run(&self, arguments: &[Value], _context: &Map) -> Result<Value> {
+        Error::expect_built_in_function_argument_amount(self, 2, arguments.len())?;
+
+        let left = arguments.get(0).unwrap();
+        let right = arguments.get(1).unwrap();
+
+        if left == right {
+            Ok(Value::Empty)
+        } else {
+            Err(Error::AssertEqualFailed {
+                expected: left.clone(),
+                actual: right.clone(),
+            })
+        }
+    }
+}
diff --git a/src/built_in_functions/mod.rs b/src/built_in_functions/mod.rs
index 28b2a31..ae50ff0 100644
--- a/src/built_in_functions/mod.rs
+++ b/src/built_in_functions/mod.rs
@@ -1,10 +1,13 @@
 use crate::{Map, Result, Value};
 
+mod assert;
 mod fs;
 mod output;
 mod r#type;
 
-pub const BUILT_IN_FUNCTIONS: [&dyn BuiltInFunction; 5] = [
+pub const BUILT_IN_FUNCTIONS: [&dyn BuiltInFunction; 7] = [
+    &assert::Assert,
+    &assert::AssertEqual,
     &fs::Read,
     &fs::Write,
     &fs::Append,
diff --git a/src/built_in_functions/type.rs b/src/built_in_functions/type.rs
index f9b3f80..2756aba 100644
--- a/src/built_in_functions/type.rs
+++ b/src/built_in_functions/type.rs
@@ -8,7 +8,7 @@ impl BuiltInFunction for Type {
     }
 
     fn run(&self, arguments: &[Value], context: &Map) -> Result<Value> {
-        Error::expect_function_argument_amount("type", 1, arguments.len())?;
+        Error::expect_built_in_function_argument_amount(self, 1, arguments.len())?;
 
         if arguments.len() == 1 {
             let type_definition = arguments.first().unwrap().r#type(context)?;
diff --git a/src/error.rs b/src/error.rs
index 4dc7b77..f0e81e7 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -5,7 +5,7 @@
 
 use tree_sitter::{Node, Point};
 
-use crate::{value::Value, Identifier, TypeDefinition};
+use crate::{value::Value, BuiltInFunction, Identifier, TypeDefinition};
 
 use std::{fmt, io, num::ParseFloatError, string::FromUtf8Error, sync::PoisonError, time};
 
@@ -166,8 +166,8 @@ impl Error {
         }
     }
 
-    pub fn expect_function_argument_amount(
-        tool_name: &'static str,
+    pub fn expect_built_in_function_argument_amount<F: BuiltInFunction>(
+        function: &F,
         expected: usize,
         actual: usize,
     ) -> Result<()> {
@@ -175,7 +175,7 @@ impl Error {
             Ok(())
         } else {
             Err(Error::ExpectedToolArgumentAmount {
-                tool_name,
+                tool_name: function.name(),
                 expected,
                 actual,
             })