diff --git a/scripts/pr-review.py b/scripts/pr-review.py
index a175d20..55fba73 100644
--- a/scripts/pr-review.py
+++ b/scripts/pr-review.py
@@ -47,11 +47,13 @@
 DEFAULT_MODEL_DEEP = "gpt-5.6-terra"
 DEFAULT_TEMPERATURE = 0.2
 DEFAULT_MAX_COMPLETION_TOKENS = 8192
-DEEP_MAX_COMPLETION_TOKENS = 25000
+# max_completion_tokens is shared by reasoning and visible output. At xhigh
+# effort, 25000 was consumed by reasoning alone and produced an empty review.
+DEEP_MAX_COMPLETION_TOKENS = 64000
 DEFAULT_LLM_TIMEOUT_SECONDS = 120
 DEEP_LLM_TIMEOUT_SECONDS = 300
 FAST_REASONING_EFFORT = "low"
-DEEP_REASONING_EFFORT = "medium"
+DEEP_REASONING_EFFORT = "xhigh"
 
 
 class LLMReviewError(RuntimeError):
diff --git a/tests/test_pr_review_routing.py b/tests/test_pr_review_routing.py
index c207a5a..a8f534b 100644
--- a/tests/test_pr_review_routing.py
+++ b/tests/test_pr_review_routing.py
@@ -40,7 +40,7 @@ def test_model_defaults_and_mode_routing(self):
             self.assertEqual(module.model_for_mode("docs"), "gpt-5.6-luna")
             self.assertEqual(module.model_for_mode("deep"), "gpt-5.6-terra")
             self.assertEqual(module.FAST_REASONING_EFFORT, "low")
-            self.assertEqual(module.DEEP_REASONING_EFFORT, "medium")
+            self.assertEqual(module.DEEP_REASONING_EFFORT, "xhigh")
 
     def test_gpt_5_6_payloads_pin_the_requested_reasoning_effort(self):
         module = load_pr_review_module()
@@ -56,13 +56,15 @@ def test_gpt_5_6_payloads_pin_the_requested_reasoning_effort(self):
             "system prompt",
             "diff",
             reasoning_effort=module.DEEP_REASONING_EFFORT,
+            max_completion_tokens=module.DEEP_MAX_COMPLETION_TOKENS,
         )
 
         self.assertEqual(ordinary_payload["model"], "gpt-5.6-luna")
         self.assertEqual(ordinary_payload["reasoning_effort"], "low")
         self.assertEqual(ordinary_payload["max_completion_tokens"], 8192)
         self.assertEqual(deep_payload["model"], "gpt-5.6-terra")
-        self.assertEqual(deep_payload["reasoning_effort"], "medium")
+        self.assertEqual(deep_payload["reasoning_effort"], "xhigh")
+        self.assertEqual(deep_payload["max_completion_tokens"], 64000)
 
     def test_model_repository_variable_overrides(self):
         module = load_pr_review_module()