diff --git a/src/codemodder/codetf/v2/codetf.py b/src/codemodder/codetf/v2/codetf.py
index 863fe527..c4920179 100644
--- a/src/codemodder/codetf/v2/codetf.py
+++ b/src/codemodder/codetf/v2/codetf.py
@@ -11,7 +11,7 @@
 from enum import Enum
 from typing import TYPE_CHECKING, Optional
 
-from pydantic import BaseModel, model_validator
+from pydantic import BaseModel, ConfigDict, model_validator
 
 from codemodder import __version__
 
@@ -21,9 +21,6 @@
 from ..common import Change as CommonChange
 from ..common import (
     CodeTFWriter,
-)
-from ..common import Finding as CommonFinding
-from ..common import (
     Rule,
 )
 
@@ -153,7 +150,12 @@ def validate_description(self):
         return self
 
 
-class Finding(CommonFinding):
+class Finding(BaseModel):
+    id: Optional[str] = None
+    rule: Rule
+
+    model_config = ConfigDict(frozen=True)
+
     def to_unfixed_finding(
         self,
         *,
@@ -172,7 +174,7 @@ def to_unfixed_finding(
     def with_rule(self, name: str, url: Optional[str]) -> Finding:
         return Finding(
             id=self.id,
-            rule=Rule(id=self.rule.id, name=name, url=url) if self.rule else None,
+            rule=Rule(id=self.rule.id, name=name, url=url),
         )
 
 
diff --git a/tests/test_codetf.py b/tests/test_codetf.py
index 5c9bab57..de59783b 100644
--- a/tests/test_codetf.py
+++ b/tests/test_codetf.py
@@ -6,7 +6,17 @@
 import requests
 from pydantic import ValidationError
 
-from codemodder.codetf import Change, ChangeSet, CodeTF, DiffSide, Reference, Result
+from codemodder.codetf import (
+    Change,
+    ChangeSet,
+    CodeTF,
+    DiffSide,
+    Finding,
+    Reference,
+    Result,
+    Rule,
+)
+from codemodder.codetf.v3.codetf import Finding as FindingV3
 
 
 @pytest.fixture(autouse=True)
@@ -167,3 +177,12 @@ def test_still_invalidates_bad_value(bad_value):
 
     with pytest.raises(ValidationError):
         Change.model_validate(json)
+
+
+def test_v2_finding_id_optional():
+    Finding(id=None, rule=Rule(id="foo", name="whatever"))
+
+
+def test_v3_finding_id_not_optional():
+    with pytest.raises(ValidationError):
+        FindingV3(id=None, rule=Rule(id="foo", name="whatever"))  # type: ignore[arg-type]