diff --git a/src/cliproxy/config/thinking-config.ts b/src/cliproxy/config/thinking-config.ts
index bf0dfa99..5afe0b3b 100644
--- a/src/cliproxy/config/thinking-config.ts
+++ b/src/cliproxy/config/thinking-config.ts
@@ -124,6 +124,15 @@ export function getThinkingValueForTier(
   if (providerOverride) {
     return providerOverride;
   }
+
+  // Codex effort aliases historically defaulted to xhigh/high/medium per tier.
+  // Preserve this behavior when settings are canonicalized (suffix-stripped).
+  if (provider === 'codex') {
+    if (tier === 'opus') return 'xhigh';
+    if (tier === 'sonnet') return 'high';
+    return 'medium';
+  }
+
   // Fall back to global tier default (with null guard, uses centralized defaults)
   return thinkingConfig.tier_defaults?.[tier] ?? DEFAULT_THINKING_TIER_DEFAULTS[tier];
 }
@@ -294,16 +303,6 @@ export function applyThinkingConfig(
         continue;
       }
 
-      // Validate/clamp tier thinking against this specific tier model capabilities.
-      const tierValidation = validateThinking(tierProvider, normalizedTierModel, tierThinkingValue);
-      if (tierValidation.warning && shouldShowWarnings(thinkingConfig)) {
-        console.warn(warn(tierValidation.warning));
-      }
-      tierThinkingValue = tierValidation.value;
-      if (isThinkingOffValue(tierThinkingValue)) {
-        continue;
-      }
-
       result[tierVar] = applyThinkingSuffixForProvider(model, tierThinkingValue, tierProvider);
     }
   }