diff --git a/lexer/annotations.py b/lexer/annotations.py
index f72f81a..3ee18af 100644
--- a/lexer/annotations.py
+++ b/lexer/annotations.py
@@ -1,4 +1,5 @@
 from lexer.base import Lexer
+from lexer.keyword import ANNOTATION_KEYWORDS
 from lexer.token import TokenType
 
 
@@ -86,7 +87,10 @@ class AnnotationLexer(Lexer):
         """
         while self.peek().isalnum() or self.peek() == "_":
             self.advance()
-        self.add_token(TokenType.IDENTIFIER)
+        
+        lexeme: str = self.source[self.start : self.idx]
+        token_type: TokenType = ANNOTATION_KEYWORDS.get(lexeme, TokenType.IDENTIFIER)
+        self.add_token(token_type)
 
     def scan_comment(self):
         """Scan the rest of a comment and add it as a token
diff --git a/lexer/keyword.py b/lexer/keyword.py
index a4f03cf..b66f21a 100644
--- a/lexer/keyword.py
+++ b/lexer/keyword.py
@@ -1,9 +1,16 @@
 from lexer.token import TokenType
 
-KEYWORDS: dict[str, TokenType] = {
+ANNOTATION_KEYWORDS: dict[str, TokenType] = {
+    "True": TokenType.TRUE,
+    "False": TokenType.FALSE,
+    "None": TokenType.NONE,
+}
+
+MIDAS_KEYWORDS: dict[str, TokenType] = {
     "type": TokenType.TYPE,
     "op": TokenType.OP,
     "constraint": TokenType.CONSTRAINT,
     "true": TokenType.TRUE,
     "false": TokenType.FALSE,
+    "none": TokenType.NONE,
 }
diff --git a/lexer/midas.py b/lexer/midas.py
index 86bfafe..42d8e6b 100644
--- a/lexer/midas.py
+++ b/lexer/midas.py
@@ -1,5 +1,5 @@
 from lexer.base import Lexer
-from lexer.keyword import KEYWORDS
+from lexer.keyword import MIDAS_KEYWORDS
 from lexer.token import TokenType
 
 
@@ -102,7 +102,7 @@ class MidasLexer(Lexer):
             self.advance()
 
         lexeme: str = self.source[self.start : self.idx]
-        token_type: TokenType = KEYWORDS.get(lexeme, TokenType.IDENTIFIER)
+        token_type: TokenType = MIDAS_KEYWORDS.get(lexeme, TokenType.IDENTIFIER)
         self.add_token(token_type)
 
     def scan_comment(self):