diff --git a/joj3_config_generator/models/common.py b/joj3_config_generator/models/common.py
index 438f77d..061ecf1 100644
--- a/joj3_config_generator/models/common.py
+++ b/joj3_config_generator/models/common.py
@@ -3,6 +3,7 @@ from typing import Union
 import humanfriendly
 
 
+# FIXME: we don't need to compact for int
 class Memory(int):
     def __new__(cls, value: Union[str, int]) -> "Memory":
         if isinstance(value, str):
diff --git a/joj3_config_generator/models/task.py b/joj3_config_generator/models/task.py
index f3171d0..2b39cad 100644
--- a/joj3_config_generator/models/task.py
+++ b/joj3_config_generator/models/task.py
@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta
+from enum import StrEnum
 from pathlib import Path
 from typing import Any, Dict, List, Type
 
@@ -80,6 +81,18 @@ class Limit(BaseModel):
         raise ValueError("Must be a string")
 
 
+class Parser(StrEnum):
+    CLANG_TIDY = "clangtidy"
+    CPPCHECK = "cppcheck"
+    CPPLINT = "cpplint"
+    KEYWORD = "keyword"
+    RESULT_STATUS = "result-status"
+    RESULT_DETAIL = "result-detail"
+    DUMMY = "dummy"
+    FILE = "file"
+    DIFF = "diff"
+
+
 class Stage(BaseModel):
     name: str = ""  # Stage name
     env: List[str] = []
@@ -88,7 +101,7 @@ class Stage(BaseModel):
     in_: str = Field("", alias="in")
     out_: str = Field("", alias="out")
     score: int = 0
-    parsers: List[str] = []  # list of parsers
+    parsers: List[Parser] = []  # list of parsers
     limit: Limit = Limit()
     dummy: ParserDummy = ParserDummy()
     result_status: ParserDummy = Field(ParserDummy(), alias="result-status")
diff --git a/joj3_config_generator/processers/task.py b/joj3_config_generator/processers/task.py
index ddca853..d18b341 100644
--- a/joj3_config_generator/processers/task.py
+++ b/joj3_config_generator/processers/task.py
@@ -6,6 +6,7 @@ from typing import Any, Callable, Dict, List, Tuple
 from joj3_config_generator.models import result, task
 from joj3_config_generator.models.common import Memory, Time
 from joj3_config_generator.models.const import JOJ3_CONFIG_ROOT
+from joj3_config_generator.models.task import Parser as parser_enum
 
 
 def get_conf_stage(
@@ -32,7 +33,7 @@ def get_conf_stage(
         if parser in processed_dict:
             fn, parser_model = processed_dict[parser]
             fn(parser_model, conf_stage.parsers[idx])
-        elif parser == "diff":
+        elif parser == parser_enum.DIFF:
             fix_diff(
                 task_stage,
                 conf_stage.parsers[idx],
@@ -46,16 +47,18 @@ def get_conf_stage(
 
 def get_processed_dict(
     task_stage: task.Stage,
-) -> Dict[str, Tuple[Callable[[Any, result.Parser], None], Any]]:
-    processed_dict: Dict[str, Tuple[Callable[[Any, result.Parser], None], Any]] = {
-        "clangtidy": (fix_keyword, task_stage.clangtidy),
-        "keyword": (fix_keyword, task_stage.keyword),
-        "cppcheck": (fix_keyword, task_stage.cppcheck),
-        "cpplint": (fix_keyword, task_stage.cpplint),
-        "result-detail": (fix_result_detail, task_stage.result_detail),
-        "dummy": (fix_dummy, task_stage.dummy),
-        "result-status": (fix_dummy, task_stage.result_status),
-        "file": (fix_file, task_stage.file),
+) -> Dict[parser_enum, Tuple[Callable[[Any, result.Parser], None], Any]]:
+    processed_dict: Dict[
+        parser_enum, Tuple[Callable[[Any, result.Parser], None], Any]
+    ] = {
+        parser_enum.CLANG_TIDY: (fix_keyword, task_stage.clangtidy),
+        parser_enum.KEYWORD: (fix_keyword, task_stage.keyword),
+        parser_enum.CPPCHECK: (fix_keyword, task_stage.cppcheck),
+        parser_enum.CPPLINT: (fix_keyword, task_stage.cpplint),
+        parser_enum.RESULT_DETAIL: (fix_result_detail, task_stage.result_detail),
+        parser_enum.DUMMY: (fix_dummy, task_stage.dummy),
+        parser_enum.RESULT_STATUS: (fix_dummy, task_stage.result_status),
+        parser_enum.FILE: (fix_file, task_stage.file),
     }
     return processed_dict