diff --git a/backend/internal/service/account_test_prompt.go b/backend/internal/service/account_test_prompt.go
index fb21a3db9666..567a4007d4f9 100644
--- a/backend/internal/service/account_test_prompt.go
+++ b/backend/internal/service/account_test_prompt.go
@@ -20,6 +20,14 @@ func accountTextTestOutputLimit(prompts ...string) int {
 }
 
 const accountTestPromptContextKey = "account_test_user_prompt"
+const accountTestScheduledDefaultsContextKey = "account_test_scheduled_defaults"
+
+func resolveAntigravityTestPrompt(prompts ...string) string {
+	if len(prompts) == 0 {
+		return "."
+	}
+	return resolveAccountTestPrompt(prompts...)
+}
 
 func ValidateAccountTextTestPrompt(prompt, model, mode string) error {
 	switch strings.ToLower(strings.TrimSpace(mode)) {
diff --git a/backend/internal/service/account_test_prompt_test.go b/backend/internal/service/account_test_prompt_test.go
index 1d4f2d7140b9..633ea6940f7b 100644
--- a/backend/internal/service/account_test_prompt_test.go
+++ b/backend/internal/service/account_test_prompt_test.go
@@ -40,6 +40,37 @@ func TestAccountTestPromptBuildersPreserveUserText(t *testing.T) {
 	}
 }
 
+func TestAccountTestPromptAntigravityScheduledDefaults(t *testing.T) {
+	svc := &AntigravityGatewayService{}
+	for _, tc := range []struct {
+		name, model string
+		build       func(string, string, ...string) ([]byte, error)
+	}{
+		{"gemini", "gemini-3.1-pro", svc.buildGeminiTestRequest},
+		{"claude", "claude-sonnet-4-6", svc.buildClaudeTestRequest},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			for _, input := range []struct {
+				name    string
+				prompts []string
+				want    string
+				limit   int64
+			}{
+				{"scheduled", nil, ".", 1},
+				{"blank manual", []string{""}, "hi", 1},
+				{"custom manual", []string{"custom question"}, "custom question", 1024},
+			} {
+				t.Run(input.name, func(t *testing.T) {
+					raw, err := tc.build("project", tc.model, input.prompts...)
+					require.NoError(t, err)
+					require.Equal(t, input.want, gjson.GetBytes(raw, "request.contents.0.parts.0.text").String())
+					require.Equal(t, input.limit, gjson.GetBytes(raw, "request.generationConfig.maxOutputTokens").Int())
+				})
+			}
+		})
+	}
+}
+
 func TestAccountTestPromptAdaptiveAndOpenCodeFinalRequests(t *testing.T) {
 	prompt := "  preserve 用户原文\n"
 	account := adaptiveCNAccountTestAccount(991, PlatformDeepseek)
diff --git a/backend/internal/service/account_test_service.go b/backend/internal/service/account_test_service.go
index 89a9a02520c2..4388c9ac83f6 100644
--- a/backend/internal/service/account_test_service.go
+++ b/backend/internal/service/account_test_service.go
@@ -2495,7 +2495,11 @@ func (s *AccountTestService) testAntigravityAccountConnection(c *gin.Context, ac
 	s.sendEvent(c, TestEvent{Type: "test_start", Model: testModelID})
 
 	// 调用 AntigravityGatewayService.TestConnection（复用协议转换逻辑）
-	result, err := s.antigravityGatewayService.TestConnection(ctx, account, testModelID, c.GetString(accountTestPromptContextKey))
+	prompts := []string{c.GetString(accountTestPromptContextKey)}
+	if c.GetBool(accountTestScheduledDefaultsContextKey) {
+		prompts = nil
+	}
+	result, err := s.antigravityGatewayService.TestConnection(ctx, account, testModelID, prompts...)
 	if err != nil {
 		return s.sendErrorAndEnd(c, err.Error())
 	}
@@ -3372,7 +3376,12 @@ func (s *AccountTestService) runTestBackground(ctx context.Context, accountID in
 	ginCtx, _ := gin.CreateTestContext(httptest.NewRecorder())
 	ginCtx.Request = (&http.Request{}).WithContext(ctx)
 	ginCtx.Set("account_test_event_collector", collector)
-	testErr := s.TestAccountConnection(ginCtx, accountID, modelID, resolveAccountTestPrompt(prompts...), AccountTestModeDefault, AccountTestOptions{requireSupportedModel: requireSupported})
+	ginCtx.Set(accountTestScheduledDefaultsContextKey, !requireSupported)
+	prompt := ""
+	if len(prompts) > 0 {
+		prompt = prompts[0]
+	}
+	testErr := s.TestAccountConnection(ginCtx, accountID, modelID, prompt, AccountTestModeDefault, AccountTestOptions{requireSupportedModel: requireSupported})
 	if testErr == nil {
 		testErr = ctx.Err()
 	}
diff --git a/backend/internal/service/antigravity_gateway_service.go b/backend/internal/service/antigravity_gateway_service.go
index 8861d3542d65..48da7efe77f1 100644
--- a/backend/internal/service/antigravity_gateway_service.go
+++ b/backend/internal/service/antigravity_gateway_service.go
@@ -457,7 +457,7 @@ func (s *AntigravityGatewayService) buildGeminiTestRequest(projectID, model stri
 			{
 				"role": "user",
 				"parts": []map[string]any{
-					{"text": resolveAccountTestPrompt(prompts...)},
+					{"text": resolveAntigravityTestPrompt(prompts...)},
 				},
 			},
 		},
@@ -478,7 +478,7 @@ func (s *AntigravityGatewayService) buildGeminiTestRequest(projectID, model stri
 // buildClaudeTestRequest 构建 Claude 格式测试请求并转换为 Gemini 格式
 // 使用最小 token 消耗：输入 "." + MaxTokens: 1
 func (s *AntigravityGatewayService) buildClaudeTestRequest(projectID, mappedModel string, prompts ...string) ([]byte, error) {
-	content, err := json.Marshal(resolveAccountTestPrompt(prompts...))
+	content, err := json.Marshal(resolveAntigravityTestPrompt(prompts...))
 	if err != nil {
 		return nil, err
 	}
diff --git a/backend/internal/service/codex_ticket_lifecycle.go b/backend/internal/service/codex_ticket_lifecycle.go
index 08020e8feeaf..cb9b93ffd282 100644
--- a/backend/internal/service/codex_ticket_lifecycle.go
+++ b/backend/internal/service/codex_ticket_lifecycle.go
@@ -112,6 +112,8 @@ func CodexTicketFailure(code string) CodexTicketResult {
 		"ticket_proxy_protocol": "代理协议握手失败，请核对HTTP或SOCKS协议",
 		"ticket_proxy_dns":      "代理主机DNS解析失败",
 		"ticket_proxy_connect":  "代理连接被拒绝或CONNECT失败",
+		"ticket_proxy_eof":      "连接被对端提前关闭（EOF）",
+		"ticket_proxy_reset":    "连接被对端重置",
 		"ticket_proxy_tls":      "代理TLS证书验证失败，请测试代理连接",
 	}
 	message, ok := messages[code]
diff --git a/backend/internal/service/codex_ticket_proxy.go b/backend/internal/service/codex_ticket_proxy.go
index 5586db127099..a9247f4fa566 100644
--- a/backend/internal/service/codex_ticket_proxy.go
+++ b/backend/internal/service/codex_ticket_proxy.go
@@ -8,6 +8,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"net/http/httptrace"
@@ -42,6 +43,7 @@ type CodexTicketProxyStage struct {
 }
 
 type CodexTicketProxyTestResult struct {
+	FailureDetail          string                  `json:"failure_detail,omitempty"`
 	Success                bool                    `json:"success"`
 	NetworkReachable       bool                    `json:"network_reachable"`
 	Protocol               string                  `json:"protocol"`
@@ -327,6 +329,7 @@ func (s *OpenAIGatewayService) prepareCodexTicketProxy(ctx context.Context, raw
 	if err != nil {
 		result.Code = codexTicketTransportFailureCode(err)
 		result.Message = CodexTicketFailure(result.Code).Message
+		result.FailureDetail = codexTicketProxyFailureDetail(err, normal)
 		if strings.HasPrefix(u.Scheme, "socks") && errors.Is(err, context.DeadlineExceeded) {
 			result.ProtocolSuggestion = "尝试确认该端口是否为HTTP CONNECT代理"
 		}
@@ -382,6 +385,7 @@ func (s *OpenAIGatewayService) TestCodexTicketProxy(ctx context.Context, raw str
 				result.Success = false
 				result.Code = codexTicketTransportFailureCode(followErr)
 				result.Message = CodexTicketFailure(result.Code).Message
+				result.FailureDetail = codexTicketProxyFailureDetail(followErr, normalized)
 				result.Stages = append(result.Stages, CodexTicketProxyStage{Name: "pinned_connection", Success: false, DurationMS: time.Since(started).Milliseconds(), Message: result.Message})
 				return result, nil
 			}
@@ -428,9 +432,28 @@ func codexTicketTransportFailureCode(err error) string {
 	if strings.Contains(t, "connection refused") || strings.Contains(t, "connect rejected") {
 		return "ticket_proxy_connect"
 	}
+	if errors.Is(err, io.EOF) || errors.Is(err, io.ErrUnexpectedEOF) {
+		return "ticket_proxy_eof"
+	}
+	if strings.Contains(t, "connection reset") || strings.Contains(t, "forcibly closed") {
+		return "ticket_proxy_reset"
+	}
 	return "ticket_transport"
 }
 
+func codexTicketProxyFailureDetail(err error, proxyURL string) string {
+	secrets := []string{proxyURL}
+	if parsed, parseErr := url.Parse(proxyURL); parseErr == nil && parsed.User != nil {
+		password, _ := parsed.User.Password()
+		secrets = append(secrets, parsed.User.Username(), password)
+	}
+	text := []rune(codexTicketSafeUpstreamMessage(err.Error(), secrets...))
+	if len(text) > 256 {
+		text = text[:256]
+	}
+	return string(text)
+}
+
 var ticketSensitiveValuePattern = regexp.MustCompile(`(?i)(?:bearer\s+\S+|(?:https?|socks5h?)://\S+|eyJ[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+|sk-[A-Za-z0-9_-]+|gAAAAA[A-Za-z0-9_=-]+)`)
 
 func codexTicketSafeUpstreamMessage(raw string, secretValues ...string) string {
diff --git a/backend/internal/service/codex_ticket_proxy_test.go b/backend/internal/service/codex_ticket_proxy_test.go
index e523e51247f3..adbe005acf04 100644
--- a/backend/internal/service/codex_ticket_proxy_test.go
+++ b/backend/internal/service/codex_ticket_proxy_test.go
@@ -7,6 +7,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
+	"errors"
 	"io"
 	"math/big"
 	"net"
@@ -196,3 +197,15 @@ func TestCodexTicketProxyAuthenticationFailureAndErrorRedaction(t *testing.T) {
 	require.NotContains(t, msg, "secret-value")
 	require.False(t, strings.Contains(msg, "gAAAAA"))
 }
+
+func TestCodexTicketProxyDisconnectCauseIsRedacted(t *testing.T) {
+	proxyURL := "http://diagnostic-user:diagnostic-password@proxy.example.com:8080"
+	err := &url.Error{Op: "Head", URL: proxyURL, Err: io.EOF}
+	require.Equal(t, "ticket_proxy_eof", codexTicketTransportFailureCode(err))
+	detail := codexTicketProxyFailureDetail(err, proxyURL)
+	require.Contains(t, detail, "EOF")
+	require.NotContains(t, detail, "diagnostic-user")
+	require.NotContains(t, detail, "diagnostic-password")
+	require.Equal(t, "ticket_proxy_reset", codexTicketTransportFailureCode(errors.New("read: connection reset by peer")))
+	require.LessOrEqual(t, len([]rune(codexTicketProxyFailureDetail(errors.New(strings.Repeat("failure ", 100)), proxyURL))), 256)
+}
diff --git a/frontend/src/api/admin/codexTickets.ts b/frontend/src/api/admin/codexTickets.ts
index 50890d86d19e..5443188f28cd 100644
--- a/frontend/src/api/admin/codexTickets.ts
+++ b/frontend/src/api/admin/codexTickets.ts
@@ -7,6 +7,7 @@ export interface TicketResult {
   duration_ms?: number; expires_at?: string; fingerprint?: string
 }
 export interface ProxyTestResult {
+  failure_detail?: string
   success: boolean; network_reachable: boolean; protocol: string; http_status?: number; code: string; message: string
   stages: Array<{ name: string; success: boolean; duration_ms: number; message?: string }>
   certificate_trust?: string; certificate_fingerprint?: string; protocol_suggestion?: string
diff --git a/frontend/src/components/admin/CodexTicketProxyEditor.vue b/frontend/src/components/admin/CodexTicketProxyEditor.vue
index 5be42492160e..d2378ab16b45 100644
--- a/frontend/src/components/admin/CodexTicketProxyEditor.vue
+++ b/frontend/src/components/admin/CodexTicketProxyEditor.vue
@@ -14,6 +14,7 @@
     <p v-if="error" role="alert" class="text-red-600 text-sm">{{ error }}</p>
     <div v-if="result" role="status" class="space-y-1 border p-3 text-sm">
       <p :class="result.success ? 'text-emerald-600' : 'text-amber-600'">{{ result.message }}</p>
+      <p v-if="result.failure_detail" class="break-words text-red-600">{{ result.failure_detail }}</p>
       <p v-for="(stage, index) in result.stages" :key="index">{{ t('admin.accounts.ticketProxy.stages.' + stage.name) }} · {{ stage.success ? '✓' : '✗' }} {{ stage.message }} {{ stage.duration_ms }} ms</p>
       <p v-if="result.certificate_trust">{{ t('admin.accounts.ticketProxy.trust') }}: {{ result.certificate_trust }} {{ result.certificate_fingerprint }}</p>
       <p v-if="result.protocol_suggestion">{{ result.protocol_suggestion }}</p>
diff --git a/frontend/src/components/admin/__tests__/CodexTicketProxyEditor.spec.ts b/frontend/src/components/admin/__tests__/CodexTicketProxyEditor.spec.ts
index 25d5dc3f5702..b8a5123e0a49 100644
--- a/frontend/src/components/admin/__tests__/CodexTicketProxyEditor.spec.ts
+++ b/frontend/src/components/admin/__tests__/CodexTicketProxyEditor.spec.ts
@@ -27,4 +27,11 @@ describe('draft ticket proxy editor', () => {
     expect(wrapper.get('[role="alert"]').text()).toContain('duplicate_field')
     wrapper.unmount()
   })
+  it('shows the safe transport cause supplied by the server', async () => {
+    const wrapper = mount(CodexTicketProxyEditor, { props: { modelValue: 'http://proxy.example.com:8080' } })
+    mocks.testProxy.mockResolvedValue({ success: false, network_reachable: false, code: 'ticket_proxy_eof', message: 'Connection closed', failure_detail: 'Head [redacted]: EOF', stages: [] })
+    await wrapper.findAll('button').find(b => b.text().endsWith('.test'))!.trigger('click'); await flushPromises()
+    expect(wrapper.get('[role="status"]').text()).toContain('Head [redacted]: EOF')
+    wrapper.unmount()
+  })
 })