diff --git a/apps/backend/services/orchestrator.py b/apps/backend/services/orchestrator.py
index f3d33e3..05bec3c 100755
--- a/apps/backend/services/orchestrator.py
+++ b/apps/backend/services/orchestrator.py
@@ -6,6 +6,8 @@
 from datetime import datetime
 from typing import Any, Dict, List, Optional
 
+import yaml
+
 from sqlalchemy.orm import Session
 
 from ...core.credential_service import CredentialService, StoredCredential
@@ -68,6 +70,9 @@ def generate_leaderboard(self, query: LeaderboardQuery, user_id: Optional[int] =
                 plan_metadata = self.planner_agent.create_evaluation_plan(
                     query.query, secure_models
                 )
+                plan_metadata = self._apply_user_sample_size(
+                    plan_metadata, query.sample_size
+                )
                 plan_metadata = self._attach_credential_references(
                     plan_metadata,
                     stored_credentials
@@ -408,6 +413,26 @@ def get_leaderboard_by_criteria(
             total_models=len(leaderboard_entries)
         )
 
+    @staticmethod
+    def _apply_user_sample_size(
+        plan_metadata: Dict[str, Any], sample_size: int
+    ) -> Dict[str, Any]:
+        if plan_metadata.get("config"):
+            plan_metadata["config"]["sample_size"] = sample_size
+
+        plan_yaml_raw = plan_metadata.get("plan_yaml", "")
+        if plan_yaml_raw:
+            plan_dict = yaml.safe_load(plan_yaml_raw)
+            if plan_dict.get("metadata"):
+                plan_dict["metadata"]["sample_size"] = sample_size
+            for ds in plan_dict.get("datasets", []):
+                ds["sample_size"] = sample_size
+            plan_metadata["plan_yaml"] = yaml.dump(
+                plan_dict, default_flow_style=False, allow_unicode=True
+            )
+
+        return plan_metadata
+
     def _default_plan_config(self) -> PlanConfig:
         """Create a safe default plan configuration."""
         return PlanConfig(