diff --git a/src/codemodder/codetf/common.py b/src/codemodder/codetf/common.py
index fa1086ec..7bfdee6d 100644
--- a/src/codemodder/codetf/common.py
+++ b/src/codemodder/codetf/common.py
@@ -84,3 +84,14 @@ def validate_description(self):
         if self.description is not None and not self.description:
             raise ValueError("description must not be empty")
         return self
+
+
+class Rating(BaseModel):
+    score: int
+    description: Optional[str] = None
+
+
+class FixQuality(BaseModel):
+    safetyRating: Rating
+    effectivenessRating: Rating
+    cleanlinessRating: Rating
diff --git a/src/codemodder/codetf/v2/codetf.py b/src/codemodder/codetf/v2/codetf.py
index c4920179..2528a747 100644
--- a/src/codemodder/codetf/v2/codetf.py
+++ b/src/codemodder/codetf/v2/codetf.py
@@ -21,6 +21,7 @@
 from ..common import Change as CommonChange
 from ..common import (
     CodeTFWriter,
+    FixQuality,
     Rule,
 )
 
@@ -104,17 +105,6 @@ class Strategy(Enum):
     deterministic = "deterministic"
 
 
-class Rating(BaseModel):
-    score: int
-    description: Optional[str] = None
-
-
-class FixQuality(BaseModel):
-    safetyRating: Rating
-    effectivenessRating: Rating
-    cleanlinessRating: Rating
-
-
 class ChangeSet(BaseModel):
     """A set of changes made to a file at `path`"""
 
diff --git a/src/codemodder/codetf/v3/codetf.py b/src/codemodder/codetf/v3/codetf.py
index 255b8cec..dc5ccff1 100644
--- a/src/codemodder/codetf/v3/codetf.py
+++ b/src/codemodder/codetf/v3/codetf.py
@@ -5,7 +5,7 @@
 
 from pydantic import BaseModel, model_validator
 
-from ..common import Change, CodeTFWriter, Finding
+from ..common import Change, CodeTFWriter, Finding, FixQuality
 from ..v2.codetf import Finding as V2Finding
 
 
@@ -41,14 +41,14 @@ class FixStatus(BaseModel):
     """Metadata describing fix outcome"""
 
     status: FixStatusType
-    reason: Optional[str]
-    details: Optional[str]
+    reason: Optional[str] = None
+    details: Optional[str] = None
 
 
 class ChangeSet(BaseModel):
     path: str
     diff: str
-    changes: list[Change]
+    changes: list[Change] = []
 
 
 class Reference(BaseModel):
@@ -88,27 +88,16 @@ class FixMetadata(BaseModel):
     summary: str
     # A detailed description of the fix
     description: str
-    references: list[Reference]
+    references: list[Reference] = []
     generation: GenerationMetadata
 
 
-class Rating(BaseModel):
-    score: int
-    description: Optional[str] = None
-
-
-class FixQuality(BaseModel):
-    safetyRating: Rating
-    effectivenessRating: Rating
-    cleanlinessRating: Rating
-
-
 class FixResult(BaseModel):
     """Result corresponding to a single finding"""
 
     finding: Finding | V2Finding
     fixStatus: FixStatus
-    changeSets: list[ChangeSet]
+    changeSets: list[ChangeSet] = []
     fixMetadata: Optional[FixMetadata] = None
     fixQuality: Optional[FixQuality] = None
     # A description of the reasoning process that led to the fix