fix(examples): honor disabled sdk cost gate

Author: YAO-001

examples/optimization/eval_optimize_loop/run_pipeline.py

@@ -594,11 +594,12 @@ def _sdk_gate_decision(
             f"accept: validation improvement {improvement:.3f} meets threshold {min_improvement:.3f}"
         )
 
-    if total_cost > max_cost:
-        accepted = False
-        reasons.append(f"reject: total SDK cost {total_cost:.3f} exceeds budget {max_cost:.3f}")
-    else:
-        reasons.append(f"accept: total SDK cost {total_cost:.3f} is within budget {max_cost:.3f}")
+    if max_cost is not None:
+        if total_cost > max_cost:
+            accepted = False
+            reasons.append(f"reject: total SDK cost {total_cost:.3f} exceeds budget {max_cost:.3f}")
+        else:
+            reasons.append(f"accept: total SDK cost {total_cost:.3f} is within budget {max_cost:.3f}")
 
     if accepted:
         reasons.append("accept: SDK aggregate gate passed")

examples/optimization/eval_optimize_loop/tests/test_sdk_backend.py

@@ -14,6 +14,7 @@
 from examples.optimization.eval_optimize_loop.run_pipeline import DEFAULT_TRAIN
 from examples.optimization.eval_optimize_loop.run_pipeline import DEFAULT_VAL
 from examples.optimization.eval_optimize_loop.run_pipeline import _parse_target_prompt_paths
+from examples.optimization.eval_optimize_loop.run_pipeline import _sdk_gate_decision
 from examples.optimization.eval_optimize_loop.run_pipeline import run_pipeline
 
 
@@ -551,6 +552,26 @@ def test_run_pipeline_mode_sdk_custom_gate_rejects_cost_over_budget(tmp_path: Pa
     assert any("cost" in reason for reason in decision.reasons)
 
 
+def test_sdk_gate_decision_skips_disabled_cost_gate_but_keeps_quality_threshold():
+    decision = _sdk_gate_decision(
+        candidate_id="sdk_best",
+        sdk_summary={
+            "status": "SUCCEEDED",
+            "pass_rate_improvement": 0.005,
+            "total_llm_cost": 1000.0,
+        },
+        gate_config={
+            "min_val_score_improvement": 0.01,
+            "max_total_cost": None,
+        },
+    )
+
+    assert decision.accepted is False
+    assert any("validation improvement" in reason for reason in decision.reasons)
+    assert not any("cost" in reason for reason in decision.reasons)
+    assert decision.total_run_cost == 1000.0
+
+
 @pytest.mark.parametrize(
     ("field_name", "field_value"),
     [