diff --git a/internal/util/thinking.go b/internal/util/thinking.go
index bcf92c5b..37200980 100644
--- a/internal/util/thinking.go
+++ b/internal/util/thinking.go
@@ -113,45 +113,3 @@ func defaultReasoningLevel(levels []string) string {
 	}
 	return ""
 }
-
-// standardReasoningEfforts defines the canonical set of reasoning effort levels.
-// This serves as the single source of truth for valid effort values.
-var standardReasoningEfforts = []string{"none", "auto", "minimal", "low", "medium", "high", "xhigh"}
-
-// IsValidReasoningEffort checks if the given effort string is a valid reasoning effort level.
-// This is a registry-independent check against the standard effort levels.
-func IsValidReasoningEffort(effort string) bool {
-	if effort == "" {
-		return false
-	}
-	lowered := strings.ToLower(strings.TrimSpace(effort))
-	for _, e := range standardReasoningEfforts {
-		if e == lowered {
-			return true
-		}
-	}
-	return false
-}
-
-// NormalizeReasoningEffort normalizes a reasoning effort string to its canonical form.
-// It first tries registry-based normalization if a model is provided, then falls back
-// to the standard effort levels. Returns empty string and false if invalid.
-func NormalizeReasoningEffort(model, effort string) (string, bool) {
-	if effort == "" {
-		return "", false
-	}
-	lowered := strings.ToLower(strings.TrimSpace(effort))
-
-	if model != "" {
-		if normalized, ok := NormalizeReasoningEffortLevel(model, effort); ok {
-			return normalized, true
-		}
-	}
-
-	for _, e := range standardReasoningEfforts {
-		if e == lowered {
-			return e, true
-		}
-	}
-	return "", false
-}
diff --git a/internal/util/thinking_suffix.go b/internal/util/thinking_suffix.go
index 1a1a8715..c2d806ad 100644
--- a/internal/util/thinking_suffix.go
+++ b/internal/util/thinking_suffix.go
@@ -58,11 +58,14 @@ func NormalizeThinkingModel(modelName string) (string, map[string]any) {
 					baseModel = modelName[:idx]
 					budgetOverride = &parsed
 					matched = true
-				} else if IsValidReasoningEffort(value) {
+				} else {
 					baseModel = modelName[:idx]
-					effort := strings.ToLower(strings.TrimSpace(value))
-					reasoningEffort = &effort
-					matched = true
+					if normalized, ok := NormalizeReasoningEffortLevel(baseModel, value); ok {
+						reasoningEffort = &normalized
+						matched = true
+					} else {
+						baseModel = modelName
+					}
 				}
 			}
 		} else if strings.HasSuffix(lower, "-thinking") {
@@ -186,9 +189,7 @@ func ReasoningEffortFromMetadata(metadata map[string]any) (string, bool) {
 		return "", false
 	}
 	if effort != nil && *effort != "" {
-		if IsValidReasoningEffort(*effort) {
-			return strings.ToLower(strings.TrimSpace(*effort)), true
-		}
+		return strings.ToLower(strings.TrimSpace(*effort)), true
 	}
 	if budget != nil {
 		switch *budget {
@@ -210,9 +211,9 @@ func ThinkingEffortToBudget(model, effort string) (int, bool) {
 	if effort == "" {
 		return 0, false
 	}
-	normalized, ok := NormalizeReasoningEffort(model, effort)
+	normalized, ok := NormalizeReasoningEffortLevel(model, effort)
 	if !ok {
-		return 0, false
+		normalized = strings.ToLower(strings.TrimSpace(effort))
 	}
 	switch normalized {
 	case "none":