diff --git a/app/services/refractor_boost.py b/app/services/refractor_boost.py
index 37d6ec1..321c34c 100644
--- a/app/services/refractor_boost.py
+++ b/app/services/refractor_boost.py
@@ -282,12 +282,12 @@ def apply_pitcher_boost(ratings_dict: dict, tb_budget: float = 1.5) -> dict:
 
 def compute_variant_hash(
     player_id: int,
-    evolution_tier: int,
+    refractor_tier: int,
     cosmetics: list[str] | None = None,
 ) -> int:
     """Compute a stable, deterministic variant identifier for a boosted card.
 
-    Hashes the combination of player_id, evolution_tier, and an optional sorted
+    Hashes the combination of player_id, refractor_tier, and an optional sorted
     list of cosmetic identifiers to produce a compact integer suitable for use
     as a database variant key.  The result is derived from the first 8 hex
     characters of a SHA-256 digest, so collisions are extremely unlikely in
@@ -298,7 +298,7 @@ def compute_variant_hash(
 
     Args:
         player_id: Player primary key.
-        evolution_tier: Refractor tier (0–4) the card has reached.
+        refractor_tier: Refractor tier (0–4) the card has reached.
         cosmetics: Optional list of cosmetic tag strings (e.g. special art
             identifiers).  Order is normalised — callers need not sort.
 
@@ -307,7 +307,7 @@ def compute_variant_hash(
     """
     inputs = {
         "player_id": player_id,
-        "evolution_tier": evolution_tier,
+        "refractor_tier": refractor_tier,
         "cosmetics": sorted(cosmetics or []),
     }
     raw = hashlib.sha256(json.dumps(inputs, sort_keys=True).encode()).hexdigest()
diff --git a/tests/test_refractor_boost.py b/tests/test_refractor_boost.py
index f7506f4..3c5e97a 100644
--- a/tests/test_refractor_boost.py
+++ b/tests/test_refractor_boost.py
@@ -809,7 +809,7 @@ class TestVariantHash:
     """
 
     def test_deterministic(self):
-        """Same (player_id, evolution_tier, cosmetics) inputs produce the
+        """Same (player_id, refractor_tier, cosmetics) inputs produce the
         same hash on every call.
 
         What: Call compute_variant_hash 20 times with the same arguments and
@@ -827,8 +827,8 @@ class TestVariantHash:
     def test_different_tiers_different_hash(self):
         """Tier 1 and tier 2 for the same player produce different hashes.
 
-        What: Compare compute_variant_hash(player_id=1, evolution_tier=1)
-        vs compute_variant_hash(player_id=1, evolution_tier=2).
+        What: Compare compute_variant_hash(player_id=1, refractor_tier=1)
+        vs compute_variant_hash(player_id=1, refractor_tier=2).
 
         Why: Each Refractor tier represents a distinct card version.  If two
         tiers produced the same hash, the DB unique-key constraint on variant
@@ -841,8 +841,8 @@ class TestVariantHash:
     def test_different_players_different_hash(self):
         """Same tier for different players produces different hashes.
 
-        What: Compare compute_variant_hash(player_id=10, evolution_tier=1)
-        vs compute_variant_hash(player_id=11, evolution_tier=1).
+        What: Compare compute_variant_hash(player_id=10, refractor_tier=1)
+        vs compute_variant_hash(player_id=11, refractor_tier=1).
 
         Why: Each player's Refractor card is a distinct asset.  If two players
         at the same tier shared a hash, their boosted variants could not be