diff --git a/app/Actions/CreateBucketAction.php b/app/Actions/CreateBucketAction.php
index 0397bb7..e19771f 100644
--- a/app/Actions/CreateBucketAction.php
+++ b/app/Actions/CreateBucketAction.php
@@ -77,12 +77,10 @@ public function execute(
      */
     private function validateTypeConstraints(BucketTypeEnum $type, BucketAllocationTypeEnum $allocationType): void
     {
-        if ($type === BucketTypeEnum::OVERFLOW && $allocationType !== BucketAllocationTypeEnum::UNLIMITED) {
-            throw new InvalidArgumentException('Overflow buckets must use unlimited allocation type');
-        }
-
-        if ($type !== BucketTypeEnum::OVERFLOW && $allocationType === BucketAllocationTypeEnum::UNLIMITED) {
-            throw new InvalidArgumentException('Only overflow buckets can use unlimited allocation type');
+        $allowedTypes = $type->getAllowedAllocationTypes();
+        if (! in_array($allocationType, $allowedTypes, true)) {
+            $allowed = implode(', ', array_map(fn ($t) => $t->value, $allowedTypes));
+            throw new InvalidArgumentException("Invalid allocation type for {$type->value} bucket. Allowed: {$allowed}");
         }
     }
 
diff --git a/app/Enums/BucketTypeEnum.php b/app/Enums/BucketTypeEnum.php
index d7bcc84..4c1e891 100644
--- a/app/Enums/BucketTypeEnum.php
+++ b/app/Enums/BucketTypeEnum.php
@@ -21,4 +21,17 @@ public static function values(): array
     {
         return array_column(self::cases(), 'value');
     }
+
+    /**
+     * Get valid allocation types for this bucket type.
+     *
+     * @return BucketAllocationTypeEnum[]
+     */
+    public function getAllowedAllocationTypes(): array
+    {
+        return match ($this) {
+            self::NEED, self::WANT => [BucketAllocationTypeEnum::FIXED_LIMIT, BucketAllocationTypeEnum::PERCENTAGE],
+            self::OVERFLOW => [BucketAllocationTypeEnum::UNLIMITED],
+        };
+    }
 }
diff --git a/app/Http/Controllers/BucketController.php b/app/Http/Controllers/BucketController.php
index 19c2b45..e5f9997 100644
--- a/app/Http/Controllers/BucketController.php
+++ b/app/Http/Controllers/BucketController.php
@@ -178,17 +178,13 @@ private function validateBucketTypeConstraints(
         Scenario $scenario,
         ?Bucket $excludeBucket = null
     ): ?JsonResponse {
-        if ($type === BucketTypeEnum::OVERFLOW && $allocationType !== BucketAllocationTypeEnum::UNLIMITED) {
-            return response()->json([
-                'message' => 'Validation failed.',
-                'errors' => ['allocation_type' => ['Overflow buckets must use unlimited allocation type.']],
-            ], 422);
-        }
+        $allowedTypes = $type->getAllowedAllocationTypes();
+        if (! in_array($allocationType, $allowedTypes, true)) {
+            $allowed = implode(', ', array_map(fn ($t) => $t->getLabel(), $allowedTypes));
 
-        if ($type !== BucketTypeEnum::OVERFLOW && $allocationType === BucketAllocationTypeEnum::UNLIMITED) {
             return response()->json([
                 'message' => 'Validation failed.',
-                'errors' => ['allocation_type' => ['Only overflow buckets can use unlimited allocation type.']],
+                'errors' => ['allocation_type' => ["{$type->getLabel()} buckets only support: {$allowed}."]],
             ], 422);
         }
 
diff --git a/app/Models/Bucket.php b/app/Models/Bucket.php
index fadb215..216c9c2 100644
--- a/app/Models/Bucket.php
+++ b/app/Models/Bucket.php
@@ -139,25 +139,6 @@ public function getFormattedAllocationValue(): string
         return $this->allocation_type->formatValue($this->allocation_value);
     }
 
-    /**
-     * Validation rules for bucket creation/update.
-     */
-    public static function validationRules($scenarioId = null): array
-    {
-        $rules = [
-            'name' => 'required|string|max:255',
-            'allocation_type' => 'required|in:'.implode(',', BucketAllocationTypeEnum::values()),
-            'priority' => 'required|integer|min:1',
-        ];
-
-        // Add scenario-specific priority uniqueness if scenario ID provided
-        if ($scenarioId) {
-            $rules['priority'] .= '|unique:buckets,priority,NULL,id,scenario_id,'.$scenarioId;
-        }
-
-        return $rules;
-    }
-
     /**
      * Get allocation value validation rules based on type.
      */
diff --git a/tests/Unit/Actions/CreateBucketActionTest.php b/tests/Unit/Actions/CreateBucketActionTest.php
index 2c86fa5..aac2d0c 100644
--- a/tests/Unit/Actions/CreateBucketActionTest.php
+++ b/tests/Unit/Actions/CreateBucketActionTest.php
@@ -127,7 +127,7 @@ public function test_default_type_is_need(): void
     public function test_overflow_bucket_must_use_unlimited_allocation(): void
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Overflow buckets must use unlimited allocation type');
+        $this->expectExceptionMessage('Invalid allocation type for overflow bucket. Allowed: unlimited');
 
         $this->action->execute(
             $this->scenario,
@@ -141,7 +141,7 @@ public function test_overflow_bucket_must_use_unlimited_allocation(): void
     public function test_non_overflow_bucket_cannot_use_unlimited_allocation(): void
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Only overflow buckets can use unlimited allocation type');
+        $this->expectExceptionMessage('Invalid allocation type for need bucket. Allowed: fixed_limit, percentage');
 
         $this->action->execute(
             $this->scenario,
@@ -174,7 +174,7 @@ public function test_cannot_create_second_overflow_bucket(): void
     public function test_want_bucket_cannot_use_unlimited_allocation(): void
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Only overflow buckets can use unlimited allocation type');
+        $this->expectExceptionMessage('Invalid allocation type for want bucket. Allowed: fixed_limit, percentage');
 
         $this->action->execute(
             $this->scenario,
diff --git a/tests/Unit/Enums/BucketTypeEnumTest.php b/tests/Unit/Enums/BucketTypeEnumTest.php
index a777808..142ad18 100644
--- a/tests/Unit/Enums/BucketTypeEnumTest.php
+++ b/tests/Unit/Enums/BucketTypeEnumTest.php
@@ -2,6 +2,7 @@
 
 namespace Tests\Unit\Enums;
 
+use App\Enums\BucketAllocationTypeEnum;
 use App\Enums\BucketTypeEnum;
 use PHPUnit\Framework\TestCase;
 
@@ -30,4 +31,30 @@ public function test_values_returns_all_string_values(): void
         $this->assertContains('want', $values);
         $this->assertContains('overflow', $values);
     }
+
+    public function test_need_allows_fixed_limit_and_percentage(): void
+    {
+        $allowed = BucketTypeEnum::NEED->getAllowedAllocationTypes();
+
+        $this->assertCount(2, $allowed);
+        $this->assertContains(BucketAllocationTypeEnum::FIXED_LIMIT, $allowed);
+        $this->assertContains(BucketAllocationTypeEnum::PERCENTAGE, $allowed);
+    }
+
+    public function test_want_allows_fixed_limit_and_percentage(): void
+    {
+        $allowed = BucketTypeEnum::WANT->getAllowedAllocationTypes();
+
+        $this->assertCount(2, $allowed);
+        $this->assertContains(BucketAllocationTypeEnum::FIXED_LIMIT, $allowed);
+        $this->assertContains(BucketAllocationTypeEnum::PERCENTAGE, $allowed);
+    }
+
+    public function test_overflow_only_allows_unlimited(): void
+    {
+        $allowed = BucketTypeEnum::OVERFLOW->getAllowedAllocationTypes();
+
+        $this->assertCount(1, $allowed);
+        $this->assertContains(BucketAllocationTypeEnum::UNLIMITED, $allowed);
+    }
 }