diff --git a/SLS_C/include/sls/bool.h b/SLS_C/include/sls/bool.h
new file mode 100644
index 0000000..0095647
--- /dev/null
+++ b/SLS_C/include/sls/bool.h
@@ -0,0 +1,14 @@
+// Kyler Olsen
+// YREA SLS
+// SLS Boolean Header
+// November 2025
+
+#ifndef SLS_BOOLEAN_H
+#define SLS_BOOLEAN_H
+
+typedef enum {
+    FALSE,
+    TRUE,
+} Boolean;
+
+#endif // SLS_BOOLEAN_H
diff --git a/SLS_C/include/sls/sls_errors.h b/SLS_C/include/sls/errors.h
similarity index 89%
rename from SLS_C/include/sls/sls_errors.h
rename to SLS_C/include/sls/errors.h
index 73d768f..6fdeda7 100644
--- a/SLS_C/include/sls/sls_errors.h
+++ b/SLS_C/include/sls/errors.h
@@ -7,11 +7,7 @@
 #define SLS_ERROR_H
 
 #include <stdint.h>
-
-typedef enum {
-    FALSE,
-    TRUE,
-} Boolean;
+#include <stddef.h>
 
 typedef struct {
     const char *message;
diff --git a/SLS_C/include/sls/lexer.h b/SLS_C/include/sls/lexer.h
index dcecdbc..e91d18b 100644
--- a/SLS_C/include/sls/lexer.h
+++ b/SLS_C/include/sls/lexer.h
@@ -8,7 +8,8 @@
 
 #include <stddef.h>
 
-#include "sls/sls_errors.h"
+#include "sls/bool.h"
+#include "sls/errors.h"
 
 extern const size_t TYPE_NAMES_SAFE_LENGTH;
 
diff --git a/SLS_C/include/sls/string.h b/SLS_C/include/sls/string.h
index 5362332..e068a0c 100644
--- a/SLS_C/include/sls/string.h
+++ b/SLS_C/include/sls/string.h
@@ -8,6 +8,8 @@
 
 #include <stddef.h>
 
+#include "bool.h"
+
 int isascii(unsigned char c);
 size_t strnlen(const char *s, size_t maxlen);
 
diff --git a/SLS_C/include/tests/lexer_test_helpers.h b/SLS_C/include/tests/lexer_test_helpers.h
index 8c3d200..4d41aa0 100644
--- a/SLS_C/include/tests/lexer_test_helpers.h
+++ b/SLS_C/include/tests/lexer_test_helpers.h
@@ -14,7 +14,8 @@
 #include <stdio.h>
 #include <math.h>
 
-#include "sls/sls_errors.h"
+#include "sls/errors.h"
+#include "sls/bool.h"
 #include "sls/lexer.h"
 #include "sls/string.h"
 #include "tests/lexer_test_helpers.h"
diff --git a/SLS_C/include/tests/tests.h b/SLS_C/include/tests/tests.h
index 5fcafc0..8d14217 100644
--- a/SLS_C/include/tests/tests.h
+++ b/SLS_C/include/tests/tests.h
@@ -8,7 +8,7 @@
 
 #include <stddef.h>
 
-#include "sls/sls_errors.h"
+#include "sls/errors.h"
 
 extern const char *TEST_FILE_NAME;
 
diff --git a/SLS_C/src/lexer.c b/SLS_C/src/lexer.c
index a748296..7eb8cc3 100644
--- a/SLS_C/src/lexer.c
+++ b/SLS_C/src/lexer.c
@@ -11,7 +11,8 @@
 #include <stdio.h>
 #include <math.h>
 
-#include "sls/sls_errors.h"
+#include "sls/errors.h"
+#include "sls/bool.h"
 #include "sls/lexer.h"
 #include "sls/string.h"
 
diff --git a/SLS_C/src/string.c b/SLS_C/src/string.c
index 0c195a1..b7a86e3 100644
--- a/SLS_C/src/string.c
+++ b/SLS_C/src/string.c
@@ -4,6 +4,7 @@
 // November 2025
 
 #include <stddef.h>
+#include <string.h>
 
 int isascii(unsigned char c) {
     return c < 128;
diff --git a/SLS_C/tests/lexer_test_helpers.c b/SLS_C/tests/lexer_test_helpers.c
index 03eba37..e200a56 100644
--- a/SLS_C/tests/lexer_test_helpers.c
+++ b/SLS_C/tests/lexer_test_helpers.c
@@ -9,7 +9,8 @@
 #include <stdio.h>
 #include <math.h>
 
-#include "sls/sls_errors.h"
+#include "sls/errors.h"
+#include "sls/bool.h"
 #include "sls/lexer.h"
 #include "sls/string.h"
 #include "tests/lexer_test_helpers.h"
diff --git a/SLS_C/tests/lexer_tests.c b/SLS_C/tests/lexer_tests.c
index fd2ab5a..fb22dd4 100644
--- a/SLS_C/tests/lexer_tests.c
+++ b/SLS_C/tests/lexer_tests.c
@@ -9,7 +9,7 @@
 #include <stdio.h>
 #include <math.h>
 
-#include "sls/sls_errors.h"
+#include "sls/errors.h"
 #include "sls/lexer.h"
 #include "sls/string.h"
 #include "tests/lexer_test_helpers.h"
diff --git a/SLS_C/tests/tests.c b/SLS_C/tests/tests.c
index 1962e78..d99d186 100644
--- a/SLS_C/tests/tests.c
+++ b/SLS_C/tests/tests.c
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <stdlib.h>
 
+#include "sls/errors.h"
 #include "tests/tests.h"
 
 const char *TEST_FILE_NAME = "TEST_FILE.SLS";
diff --git a/SLS_Tests/yaml_to_c_tests.py b/SLS_Tests/yaml_to_c_tests.py
index 9df7726..8b21ee8 100644
--- a/SLS_Tests/yaml_to_c_tests.py
+++ b/SLS_Tests/yaml_to_c_tests.py
@@ -16,7 +16,7 @@ file_headers = """\
 #include <stdio.h>
 #include <math.h>
 
-#include "sls/sls_errors.h"
+#include "sls/errors.h"
 #include "sls/lexer.h"
 #include "sls/string.h"
 #include "tests/lexer_test_helpers.h"