diff --git a/backend/internal/service/account.go b/backend/internal/service/account.go
index 6ac185dc..50fdac88 100644
--- a/backend/internal/service/account.go
+++ b/backend/internal/service/account.go
@@ -373,7 +373,11 @@ func (a *Account) GetModelMapping() map[string]string {
 		}
 		if len(result) > 0 {
 			if a.Platform == domain.PlatformAntigravity {
-				ensureAntigravityDefaultPassthrough(result, "gemini-3-flash")
+				ensureAntigravityDefaultPassthroughs(result, []string{
+					"gemini-3-flash",
+					"gemini-3.1-pro-high",
+					"gemini-3.1-pro-low",
+				})
 			}
 			return result
 		}
@@ -400,6 +404,12 @@ func ensureAntigravityDefaultPassthrough(mapping map[string]string, model string
 	mapping[model] = model
 }
 
+func ensureAntigravityDefaultPassthroughs(mapping map[string]string, models []string) {
+	for _, model := range models {
+		ensureAntigravityDefaultPassthrough(mapping, model)
+	}
+}
+
 // IsModelSupported 检查模型是否在 model_mapping 中（支持通配符）
 // 如果未配置 mapping，返回 true（允许所有模型）
 func (a *Account) IsModelSupported(requestedModel string) bool {
diff --git a/backend/internal/service/account_wildcard_test.go b/backend/internal/service/account_wildcard_test.go
index c78ce554..6a9acc68 100644
--- a/backend/internal/service/account_wildcard_test.go
+++ b/backend/internal/service/account_wildcard_test.go
@@ -268,7 +268,7 @@ func TestAccountGetMappedModel(t *testing.T) {
 	}
 }
 
-func TestAccountGetModelMapping_AntigravityEnsuresGemini3FlashPassthrough(t *testing.T) {
+func TestAccountGetModelMapping_AntigravityEnsuresGeminiDefaultPassthroughs(t *testing.T) {
 	account := &Account{
 		Platform: PlatformAntigravity,
 		Credentials: map[string]any{
@@ -282,6 +282,12 @@ func TestAccountGetModelMapping_AntigravityEnsuresGemini3FlashPassthrough(t *tes
 	if mapping["gemini-3-flash"] != "gemini-3-flash" {
 		t.Fatalf("expected gemini-3-flash passthrough to be auto-filled, got: %q", mapping["gemini-3-flash"])
 	}
+	if mapping["gemini-3.1-pro-high"] != "gemini-3.1-pro-high" {
+		t.Fatalf("expected gemini-3.1-pro-high passthrough to be auto-filled, got: %q", mapping["gemini-3.1-pro-high"])
+	}
+	if mapping["gemini-3.1-pro-low"] != "gemini-3.1-pro-low" {
+		t.Fatalf("expected gemini-3.1-pro-low passthrough to be auto-filled, got: %q", mapping["gemini-3.1-pro-low"])
+	}
 }
 
 func TestAccountGetModelMapping_AntigravityRespectsWildcardOverride(t *testing.T) {
@@ -298,6 +304,12 @@ func TestAccountGetModelMapping_AntigravityRespectsWildcardOverride(t *testing.T
 	if _, exists := mapping["gemini-3-flash"]; exists {
 		t.Fatalf("did not expect explicit gemini-3-flash passthrough when wildcard already exists")
 	}
+	if _, exists := mapping["gemini-3.1-pro-high"]; exists {
+		t.Fatalf("did not expect explicit gemini-3.1-pro-high passthrough when wildcard already exists")
+	}
+	if _, exists := mapping["gemini-3.1-pro-low"]; exists {
+		t.Fatalf("did not expect explicit gemini-3.1-pro-low passthrough when wildcard already exists")
+	}
 	if mapped := account.GetMappedModel("gemini-3-flash"); mapped != "gemini-3.1-pro-high" {
 		t.Fatalf("expected wildcard mapping to stay effective, got: %q", mapped)
 	}