diff --git a/llmcore.py b/llmcore.py
index 660f244e4..438e58d8d 100644
--- a/llmcore.py
+++ b/llmcore.py
@@ -588,7 +588,7 @@ def _apply_claude_thinking(self, payload):
                     thinking["budget_tokens"] = self.thinking_budget_tokens; payload["thinking"] = thinking
             else: payload["thinking"] = thinking
         if self.reasoning_effort:
-            effort = {'low': 'low', 'medium': 'medium', 'high': 'high', 'xhigh': 'max'}.get(self.reasoning_effort)
+            effort = {'low': 'low', 'medium': 'medium', 'high': 'high', 'xhigh': 'max', 'max': 'max'}.get(self.reasoning_effort)
             if effort: payload["output_config"] = {"effort": effort}
             else: print(f"[WARN] reasoning_effort {self.reasoning_effort!r} is unsupported for Claude output_config.effort, ignored.")
     def ask(self, prompt):