diff --git a/backend/internal/handler/openai_gateway_handler.go b/backend/internal/handler/openai_gateway_handler.go
index 2da979b5..4f28459a 100644
--- a/backend/internal/handler/openai_gateway_handler.go
+++ b/backend/internal/handler/openai_gateway_handler.go
@@ -118,6 +118,20 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 	}
 
 	setOpsRequestContext(c, "", false, body)
+	sessionHashBody := body
+	if service.IsOpenAIResponsesCompactPathForTest(c) {
+		if compactSeed := strings.TrimSpace(gjson.GetBytes(body, "prompt_cache_key").String()); compactSeed != "" {
+			c.Set(service.OpenAICompactSessionSeedKeyForTest(), compactSeed)
+		}
+		normalizedCompactBody, normalizedCompact, compactErr := service.NormalizeOpenAICompactRequestBodyForTest(body)
+		if compactErr != nil {
+			h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to normalize compact request body")
+			return
+		}
+		if normalizedCompact {
+			body = normalizedCompactBody
+		}
+	}
 
 	// 校验请求体 JSON 合法性
 	if !gjson.ValidBytes(body) {
@@ -193,7 +207,7 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 	}
 
 	// Generate session hash (header first; fallback to prompt_cache_key)
-	sessionHash := h.gatewayService.GenerateSessionHash(c, body)
+	sessionHash := h.gatewayService.GenerateSessionHash(c, sessionHashBody)
 
 	maxAccountSwitches := h.maxAccountSwitches
 	switchCount := 0
diff --git a/backend/internal/server/routes/gateway.go b/backend/internal/server/routes/gateway.go
index 13f13320..0bee1e74 100644
--- a/backend/internal/server/routes/gateway.go
+++ b/backend/internal/server/routes/gateway.go
@@ -49,6 +49,7 @@ func RegisterGatewayRoutes(
 		gateway.GET("/usage", h.Gateway.Usage)
 		// OpenAI Responses API
 		gateway.POST("/responses", h.OpenAIGateway.Responses)
+		gateway.POST("/responses/*subpath", h.OpenAIGateway.Responses)
 		gateway.GET("/responses", h.OpenAIGateway.ResponsesWebSocket)
 		// 明确阻止旧协议入口：OpenAI 仅支持 Responses API，避免客户端误解为会自动路由到其它平台。
 		gateway.POST("/chat/completions", func(c *gin.Context) {
@@ -77,6 +78,7 @@ func RegisterGatewayRoutes(
 
 	// OpenAI Responses API（不带v1前缀的别名）
 	r.POST("/responses", bodyLimit, clientRequestID, opsErrorLogger, gin.HandlerFunc(apiKeyAuth), requireGroupAnthropic, h.OpenAIGateway.Responses)
+	r.POST("/responses/*subpath", bodyLimit, clientRequestID, opsErrorLogger, gin.HandlerFunc(apiKeyAuth), requireGroupAnthropic, h.OpenAIGateway.Responses)
 	r.GET("/responses", bodyLimit, clientRequestID, opsErrorLogger, gin.HandlerFunc(apiKeyAuth), requireGroupAnthropic, h.OpenAIGateway.ResponsesWebSocket)
 
 	// Antigravity 模型列表
diff --git a/backend/internal/server/routes/gateway_test.go b/backend/internal/server/routes/gateway_test.go
new file mode 100644
index 00000000..00edd31b
--- /dev/null
+++ b/backend/internal/server/routes/gateway_test.go
@@ -0,0 +1,51 @@
+package routes
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/handler"
+	servermiddleware "github.com/Wei-Shaw/sub2api/internal/server/middleware"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func newGatewayRoutesTestRouter() *gin.Engine {
+	gin.SetMode(gin.TestMode)
+	router := gin.New()
+
+	RegisterGatewayRoutes(
+		router,
+		&handler.Handlers{
+			Gateway:       &handler.GatewayHandler{},
+			OpenAIGateway: &handler.OpenAIGatewayHandler{},
+			SoraGateway:   &handler.SoraGatewayHandler{},
+		},
+		servermiddleware.APIKeyAuthMiddleware(func(c *gin.Context) {
+			c.Next()
+		}),
+		nil,
+		nil,
+		nil,
+		nil,
+		&config.Config{},
+	)
+
+	return router
+}
+
+func TestGatewayRoutesOpenAIResponsesCompactPathIsRegistered(t *testing.T) {
+	router := newGatewayRoutesTestRouter()
+
+	for _, path := range []string{"/v1/responses/compact", "/responses/compact"} {
+		req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(`{"model":"gpt-5"}`))
+		req.Header.Set("Content-Type", "application/json")
+		w := httptest.NewRecorder()
+
+		router.ServeHTTP(w, req)
+		require.NotEqual(t, http.StatusNotFound, w.Code, "path=%s should hit OpenAI responses handler", path)
+	}
+}
diff --git a/backend/internal/service/openai_codex_transform.go b/backend/internal/service/openai_codex_transform.go
index 9bc48cf6..9a983b0d 100644
--- a/backend/internal/service/openai_codex_transform.go
+++ b/backend/internal/service/openai_codex_transform.go
@@ -77,7 +77,7 @@ type codexTransformResult struct {
 	PromptCacheKey  string
 }
 
-func applyCodexOAuthTransform(reqBody map[string]any, isCodexCLI bool) codexTransformResult {
+func applyCodexOAuthTransform(reqBody map[string]any, isCodexCLI bool, isCompact bool) codexTransformResult {
 	result := codexTransformResult{}
 	// 工具续链需求会影响存储策略与 input 过滤逻辑。
 	needsToolContinuation := NeedsToolContinuation(reqBody)
@@ -95,15 +95,26 @@ func applyCodexOAuthTransform(reqBody map[string]any, isCodexCLI bool) codexTran
 		result.NormalizedModel = normalizedModel
 	}
 
-	// OAuth 走 ChatGPT internal API 时，store 必须为 false；显式 true 也会强制覆盖。
-	// 避免上游返回 "Store must be set to false"。
-	if v, ok := reqBody["store"].(bool); !ok || v {
-		reqBody["store"] = false
-		result.Modified = true
-	}
-	if v, ok := reqBody["stream"].(bool); !ok || !v {
-		reqBody["stream"] = true
-		result.Modified = true
+	if isCompact {
+		if _, ok := reqBody["store"]; ok {
+			delete(reqBody, "store")
+			result.Modified = true
+		}
+		if _, ok := reqBody["stream"]; ok {
+			delete(reqBody, "stream")
+			result.Modified = true
+		}
+	} else {
+		// OAuth 走 ChatGPT internal API 时，store 必须为 false；显式 true 也会强制覆盖。
+		// 避免上游返回 "Store must be set to false"。
+		if v, ok := reqBody["store"].(bool); !ok || v {
+			reqBody["store"] = false
+			result.Modified = true
+		}
+		if v, ok := reqBody["stream"].(bool); !ok || !v {
+			reqBody["stream"] = true
+			result.Modified = true
+		}
 	}
 
 	// Strip parameters unsupported by codex models via the Responses API.
diff --git a/backend/internal/service/openai_codex_transform_test.go b/backend/internal/service/openai_codex_transform_test.go
index 7ee4bbc8..dd8dd07c 100644
--- a/backend/internal/service/openai_codex_transform_test.go
+++ b/backend/internal/service/openai_codex_transform_test.go
@@ -18,7 +18,7 @@ func TestApplyCodexOAuthTransform_ToolContinuationPreservesInput(t *testing.T) {
 		"tool_choice": "auto",
 	}
 
-	applyCodexOAuthTransform(reqBody, false)
+	applyCodexOAuthTransform(reqBody, false, false)
 
 	// 未显式设置 store=true，默认为 false。
 	store, ok := reqBody["store"].(bool)
@@ -53,7 +53,7 @@ func TestApplyCodexOAuthTransform_ExplicitStoreFalsePreserved(t *testing.T) {
 		"tool_choice": "auto",
 	}
 
-	applyCodexOAuthTransform(reqBody, false)
+	applyCodexOAuthTransform(reqBody, false, false)
 
 	store, ok := reqBody["store"].(bool)
 	require.True(t, ok)
@@ -72,13 +72,29 @@ func TestApplyCodexOAuthTransform_ExplicitStoreTrueForcedFalse(t *testing.T) {
 		"tool_choice": "auto",
 	}
 
-	applyCodexOAuthTransform(reqBody, false)
+	applyCodexOAuthTransform(reqBody, false, false)
 
 	store, ok := reqBody["store"].(bool)
 	require.True(t, ok)
 	require.False(t, store)
 }
 
+func TestApplyCodexOAuthTransform_CompactForcesNonStreaming(t *testing.T) {
+	reqBody := map[string]any{
+		"model":  "gpt-5.1-codex",
+		"store":  true,
+		"stream": true,
+	}
+
+	result := applyCodexOAuthTransform(reqBody, true, true)
+
+	_, hasStore := reqBody["store"]
+	require.False(t, hasStore)
+	_, hasStream := reqBody["stream"]
+	require.False(t, hasStream)
+	require.True(t, result.Modified)
+}
+
 func TestApplyCodexOAuthTransform_NonContinuationDefaultsStoreFalseAndStripsIDs(t *testing.T) {
 	// 非续链场景：未设置 store 时默认 false，并移除 input 中的 id。
 
@@ -89,7 +105,7 @@ func TestApplyCodexOAuthTransform_NonContinuationDefaultsStoreFalseAndStripsIDs(
 		},
 	}
 
-	applyCodexOAuthTransform(reqBody, false)
+	applyCodexOAuthTransform(reqBody, false, false)
 
 	store, ok := reqBody["store"].(bool)
 	require.True(t, ok)
@@ -138,7 +154,7 @@ func TestApplyCodexOAuthTransform_NormalizeCodexTools_PreservesResponsesFunction
 		},
 	}
 
-	applyCodexOAuthTransform(reqBody, false)
+	applyCodexOAuthTransform(reqBody, false, false)
 
 	tools, ok := reqBody["tools"].([]any)
 	require.True(t, ok)
@@ -158,7 +174,7 @@ func TestApplyCodexOAuthTransform_EmptyInput(t *testing.T) {
 		"input": []any{},
 	}
 
-	applyCodexOAuthTransform(reqBody, false)
+	applyCodexOAuthTransform(reqBody, false, false)
 
 	input, ok := reqBody["input"].([]any)
 	require.True(t, ok)
@@ -193,7 +209,7 @@ func TestApplyCodexOAuthTransform_CodexCLI_PreservesExistingInstructions(t *test
 		"instructions": "existing instructions",
 	}
 
-	result := applyCodexOAuthTransform(reqBody, true) // isCodexCLI=true
+	result := applyCodexOAuthTransform(reqBody, true, false) // isCodexCLI=true
 
 	instructions, ok := reqBody["instructions"].(string)
 	require.True(t, ok)
@@ -210,7 +226,7 @@ func TestApplyCodexOAuthTransform_CodexCLI_SuppliesDefaultWhenEmpty(t *testing.T
 		// 没有 instructions 字段
 	}
 
-	result := applyCodexOAuthTransform(reqBody, true) // isCodexCLI=true
+	result := applyCodexOAuthTransform(reqBody, true, false) // isCodexCLI=true
 
 	instructions, ok := reqBody["instructions"].(string)
 	require.True(t, ok)
@@ -226,7 +242,7 @@ func TestApplyCodexOAuthTransform_NonCodexCLI_OverridesInstructions(t *testing.T
 		"instructions": "old instructions",
 	}
 
-	result := applyCodexOAuthTransform(reqBody, false) // isCodexCLI=false
+	result := applyCodexOAuthTransform(reqBody, false, false) // isCodexCLI=false
 
 	instructions, ok := reqBody["instructions"].(string)
 	require.True(t, ok)
diff --git a/backend/internal/service/openai_gateway_service.go b/backend/internal/service/openai_gateway_service.go
index 9970fc19..25c7680e 100644
--- a/backend/internal/service/openai_gateway_service.go
+++ b/backend/internal/service/openai_gateway_service.go
@@ -25,6 +25,7 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/util/responseheaders"
 	"github.com/Wei-Shaw/sub2api/internal/util/urlvalidator"
 	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 	"go.uber.org/zap"
@@ -49,6 +50,8 @@ const (
 	openAIWSRetryBackoffInitialDefault = 120 * time.Millisecond
 	openAIWSRetryBackoffMaxDefault     = 2 * time.Second
 	openAIWSRetryJitterRatioDefault    = 0.2
+	openAICompactSessionSeedKey        = "openai_compact_session_seed"
+	codexCLIVersion                    = "0.104.0"
 )
 
 // OpenAI allowed headers whitelist (for non-passthrough).
@@ -1614,7 +1617,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 	}
 
 	if account.Type == AccountTypeOAuth {
-		codexResult := applyCodexOAuthTransform(reqBody, isCodexCLI)
+		codexResult := applyCodexOAuthTransform(reqBody, isCodexCLI, isOpenAIResponsesCompactPath(c))
 		if codexResult.Modified {
 			bodyModified = true
 			disablePatch()
@@ -2046,14 +2049,14 @@ func (s *OpenAIGatewayService) forwardOpenAIPassthrough(
 			return nil, fmt.Errorf("openai passthrough rejected before upstream: %s", rejectReason)
 		}
 
-		normalizedBody, normalized, err := normalizeOpenAIPassthroughOAuthBody(body)
+		normalizedBody, normalized, err := normalizeOpenAIPassthroughOAuthBody(body, isOpenAIResponsesCompactPath(c))
 		if err != nil {
 			return nil, err
 		}
 		if normalized {
 			body = normalizedBody
-			reqStream = true
 		}
+		reqStream = gjson.GetBytes(body, "stream").Bool()
 	}
 
 	logger.LegacyPrintf("service.openai_gateway",
@@ -2218,6 +2221,7 @@ func (s *OpenAIGatewayService) buildUpstreamRequestOpenAIPassthrough(
 			targetURL = buildOpenAIResponsesURL(validatedURL)
 		}
 	}
+	targetURL = appendOpenAIResponsesRequestPathSuffix(targetURL, openAIResponsesRequestPathSuffix(c))
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, targetURL, bytes.NewReader(body))
 	if err != nil {
@@ -2251,7 +2255,15 @@ func (s *OpenAIGatewayService) buildUpstreamRequestOpenAIPassthrough(
 		if chatgptAccountID := account.GetChatGPTAccountID(); chatgptAccountID != "" {
 			req.Header.Set("chatgpt-account-id", chatgptAccountID)
 		}
-		if req.Header.Get("accept") == "" {
+		if isOpenAIResponsesCompactPath(c) {
+			req.Header.Set("accept", "application/json")
+			if req.Header.Get("version") == "" {
+				req.Header.Set("version", codexCLIVersion)
+			}
+			if req.Header.Get("session_id") == "" {
+				req.Header.Set("session_id", resolveOpenAICompactSessionID(c))
+			}
+		} else if req.Header.Get("accept") == "" {
 			req.Header.Set("accept", "text/event-stream")
 		}
 		if req.Header.Get("OpenAI-Beta") == "" {
@@ -2598,6 +2610,7 @@ func (s *OpenAIGatewayService) buildUpstreamRequest(ctx context.Context, c *gin.
 	default:
 		targetURL = openaiPlatformAPIURL
 	}
+	targetURL = appendOpenAIResponsesRequestPathSuffix(targetURL, openAIResponsesRequestPathSuffix(c))
 
 	req, err := http.NewRequestWithContext(ctx, "POST", targetURL, bytes.NewReader(body))
 	if err != nil {
@@ -2634,7 +2647,17 @@ func (s *OpenAIGatewayService) buildUpstreamRequest(ctx context.Context, c *gin.
 		} else {
 			req.Header.Set("originator", "opencode")
 		}
-		req.Header.Set("accept", "text/event-stream")
+		if isOpenAIResponsesCompactPath(c) {
+			req.Header.Set("accept", "application/json")
+			if req.Header.Get("version") == "" {
+				req.Header.Set("version", codexCLIVersion)
+			}
+			if req.Header.Get("session_id") == "" {
+				req.Header.Set("session_id", resolveOpenAICompactSessionID(c))
+			}
+		} else {
+			req.Header.Set("accept", "text/event-stream")
+		}
 		if promptCacheKey != "" {
 			req.Header.Set("conversation_id", promptCacheKey)
 			req.Header.Set("session_id", promptCacheKey)
@@ -3425,6 +3448,95 @@ func buildOpenAIResponsesURL(base string) string {
 	return normalized + "/v1/responses"
 }
 
+func IsOpenAIResponsesCompactPathForTest(c *gin.Context) bool {
+	return isOpenAIResponsesCompactPath(c)
+}
+
+func OpenAICompactSessionSeedKeyForTest() string {
+	return openAICompactSessionSeedKey
+}
+
+func NormalizeOpenAICompactRequestBodyForTest(body []byte) ([]byte, bool, error) {
+	return normalizeOpenAICompactRequestBody(body)
+}
+
+func isOpenAIResponsesCompactPath(c *gin.Context) bool {
+	suffix := strings.TrimSpace(openAIResponsesRequestPathSuffix(c))
+	return suffix == "/compact" || strings.HasPrefix(suffix, "/compact/")
+}
+
+func normalizeOpenAICompactRequestBody(body []byte) ([]byte, bool, error) {
+	if len(body) == 0 {
+		return body, false, nil
+	}
+
+	normalized := []byte(`{}`)
+	for _, field := range []string{"model", "input", "instructions", "previous_response_id"} {
+		value := gjson.GetBytes(body, field)
+		if !value.Exists() {
+			continue
+		}
+		next, err := sjson.SetRawBytes(normalized, field, []byte(value.Raw))
+		if err != nil {
+			return body, false, fmt.Errorf("normalize compact body %s: %w", field, err)
+		}
+		normalized = next
+	}
+
+	if bytes.Equal(bytes.TrimSpace(body), bytes.TrimSpace(normalized)) {
+		return body, false, nil
+	}
+	return normalized, true, nil
+}
+
+func resolveOpenAICompactSessionID(c *gin.Context) string {
+	if c != nil {
+		if sessionID := strings.TrimSpace(c.GetHeader("session_id")); sessionID != "" {
+			return sessionID
+		}
+		if conversationID := strings.TrimSpace(c.GetHeader("conversation_id")); conversationID != "" {
+			return conversationID
+		}
+		if seed, ok := c.Get(openAICompactSessionSeedKey); ok {
+			if seedStr, ok := seed.(string); ok && strings.TrimSpace(seedStr) != "" {
+				return strings.TrimSpace(seedStr)
+			}
+		}
+	}
+	return uuid.NewString()
+}
+
+func openAIResponsesRequestPathSuffix(c *gin.Context) string {
+	if c == nil || c.Request == nil || c.Request.URL == nil {
+		return ""
+	}
+	normalizedPath := strings.TrimRight(strings.TrimSpace(c.Request.URL.Path), "/")
+	if normalizedPath == "" {
+		return ""
+	}
+	idx := strings.LastIndex(normalizedPath, "/responses")
+	if idx < 0 {
+		return ""
+	}
+	suffix := normalizedPath[idx+len("/responses"):]
+	if suffix == "" || suffix == "/" {
+		return ""
+	}
+	if !strings.HasPrefix(suffix, "/") {
+		return ""
+	}
+	return suffix
+}
+
+func appendOpenAIResponsesRequestPathSuffix(baseURL, suffix string) string {
+	trimmedBase := strings.TrimRight(strings.TrimSpace(baseURL), "/")
+	trimmedSuffix := strings.TrimSpace(suffix)
+	if trimmedBase == "" || trimmedSuffix == "" {
+		return trimmedBase
+	}
+	return trimmedBase + trimmedSuffix
+}
+
 func (s *OpenAIGatewayService) replaceModelInResponseBody(body []byte, fromModel, toModel string) []byte {
 	// 使用 gjson/sjson 精确替换 model 字段，避免全量 JSON 反序列化
 	if m := gjson.GetBytes(body, "model"); m.Exists() && m.Str == fromModel {
@@ -3805,8 +3917,8 @@ func extractOpenAIRequestMetaFromBody(body []byte) (model string, stream bool, p
 }
 
 // normalizeOpenAIPassthroughOAuthBody 将透传 OAuth 请求体收敛为旧链路关键行为：
-// 1) store=false 2) stream=true
-func normalizeOpenAIPassthroughOAuthBody(body []byte) ([]byte, bool, error) {
+// 1) store=false 2) 非 compact 保持 stream=true；compact 强制 stream=false
+func normalizeOpenAIPassthroughOAuthBody(body []byte, compact bool) ([]byte, bool, error) {
 	if len(body) == 0 {
 		return body, false, nil
 	}
@@ -3814,22 +3926,40 @@ func normalizeOpenAIPassthroughOAuthBody(body []byte) ([]byte, bool, error) {
 	normalized := body
 	changed := false
 
-	if store := gjson.GetBytes(normalized, "store"); !store.Exists() || store.Type != gjson.False {
-		next, err := sjson.SetBytes(normalized, "store", false)
-		if err != nil {
-			return body, false, fmt.Errorf("normalize passthrough body store=false: %w", err)
+	if compact {
+		if store := gjson.GetBytes(normalized, "store"); store.Exists() {
+			next, err := sjson.DeleteBytes(normalized, "store")
+			if err != nil {
+				return body, false, fmt.Errorf("normalize passthrough body delete store: %w", err)
+			}
+			normalized = next
+			changed = true
 		}
-		normalized = next
-		changed = true
-	}
-
-	if stream := gjson.GetBytes(normalized, "stream"); !stream.Exists() || stream.Type != gjson.True {
-		next, err := sjson.SetBytes(normalized, "stream", true)
-		if err != nil {
-			return body, false, fmt.Errorf("normalize passthrough body stream=true: %w", err)
+		if stream := gjson.GetBytes(normalized, "stream"); stream.Exists() {
+			next, err := sjson.DeleteBytes(normalized, "stream")
+			if err != nil {
+				return body, false, fmt.Errorf("normalize passthrough body delete stream: %w", err)
+			}
+			normalized = next
+			changed = true
+		}
+	} else {
+		if store := gjson.GetBytes(normalized, "store"); !store.Exists() || store.Type != gjson.False {
+			next, err := sjson.SetBytes(normalized, "store", false)
+			if err != nil {
+				return body, false, fmt.Errorf("normalize passthrough body store=false: %w", err)
+			}
+			normalized = next
+			changed = true
+		}
+		if stream := gjson.GetBytes(normalized, "stream"); !stream.Exists() || stream.Type != gjson.True {
+			next, err := sjson.SetBytes(normalized, "stream", true)
+			if err != nil {
+				return body, false, fmt.Errorf("normalize passthrough body stream=true: %w", err)
+			}
+			normalized = next
+			changed = true
 		}
-		normalized = next
-		changed = true
 	}
 
 	return normalized, changed, nil
diff --git a/backend/internal/service/openai_gateway_service_test.go b/backend/internal/service/openai_gateway_service_test.go
index 8fc29e75..3c90f9e7 100644
--- a/backend/internal/service/openai_gateway_service_test.go
+++ b/backend/internal/service/openai_gateway_service_test.go
@@ -1248,6 +1248,90 @@ func TestOpenAIValidateUpstreamBaseURLEnabledEnforcesAllowlist(t *testing.T) {
 	}
 }
 
+func TestOpenAIResponsesRequestPathSuffix(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+
+	tests := []struct {
+		name string
+		path string
+		want string
+	}{
+		{name: "exact v1 responses", path: "/v1/responses", want: ""},
+		{name: "compact v1 responses", path: "/v1/responses/compact", want: "/compact"},
+		{name: "compact alias responses", path: "/responses/compact/", want: "/compact"},
+		{name: "nested suffix", path: "/openai/v1/responses/compact/detail", want: "/compact/detail"},
+		{name: "unrelated path", path: "/v1/chat/completions", want: ""},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			c.Request = httptest.NewRequest(http.MethodPost, tt.path, nil)
+			require.Equal(t, tt.want, openAIResponsesRequestPathSuffix(c))
+		})
+	}
+}
+
+func TestOpenAIBuildUpstreamRequestOpenAIPassthroughPreservesCompactPath(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses/compact", bytes.NewReader([]byte(`{"model":"gpt-5"}`)))
+
+	svc := &OpenAIGatewayService{}
+	account := &Account{Type: AccountTypeOAuth}
+
+	req, err := svc.buildUpstreamRequestOpenAIPassthrough(c.Request.Context(), c, account, []byte(`{"model":"gpt-5"}`), "token")
+	require.NoError(t, err)
+	require.Equal(t, chatgptCodexURL+"/compact", req.URL.String())
+	require.Equal(t, "application/json", req.Header.Get("Accept"))
+	require.Equal(t, codexCLIVersion, req.Header.Get("Version"))
+	require.NotEmpty(t, req.Header.Get("Session_Id"))
+}
+
+func TestOpenAIBuildUpstreamRequestCompactForcesJSONAcceptForOAuth(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses/compact", bytes.NewReader([]byte(`{"model":"gpt-5"}`)))
+
+	svc := &OpenAIGatewayService{}
+	account := &Account{
+		Type:        AccountTypeOAuth,
+		Credentials: map[string]any{"chatgpt_account_id": "chatgpt-acc"},
+	}
+
+	req, err := svc.buildUpstreamRequest(c.Request.Context(), c, account, []byte(`{"model":"gpt-5"}`), "token", false, "", true)
+	require.NoError(t, err)
+	require.Equal(t, chatgptCodexURL+"/compact", req.URL.String())
+	require.Equal(t, "application/json", req.Header.Get("Accept"))
+	require.Equal(t, codexCLIVersion, req.Header.Get("Version"))
+	require.NotEmpty(t, req.Header.Get("Session_Id"))
+}
+
+func TestOpenAIBuildUpstreamRequestPreservesCompactPathForAPIKeyBaseURL(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/responses/compact", bytes.NewReader([]byte(`{"model":"gpt-5"}`)))
+
+	svc := &OpenAIGatewayService{cfg: &config.Config{
+		Security: config.SecurityConfig{
+			URLAllowlist: config.URLAllowlistConfig{Enabled: false},
+		},
+	}}
+	account := &Account{
+		Type:        AccountTypeAPIKey,
+		Platform:    PlatformOpenAI,
+		Credentials: map[string]any{"base_url": "https://example.com/v1"},
+	}
+
+	req, err := svc.buildUpstreamRequest(c.Request.Context(), c, account, []byte(`{"model":"gpt-5"}`), "token", false, "", false)
+	require.NoError(t, err)
+	require.Equal(t, "https://example.com/v1/responses/compact", req.URL.String())
+}
+
 // ==================== P1-08 修复：model 替换性能优化测试 ====================
 
 func TestReplaceModelInSSELine(t *testing.T) {
diff --git a/backend/internal/service/openai_oauth_passthrough_test.go b/backend/internal/service/openai_oauth_passthrough_test.go
index 0840d3b1..2191d124 100644
--- a/backend/internal/service/openai_oauth_passthrough_test.go
+++ b/backend/internal/service/openai_oauth_passthrough_test.go
@@ -236,6 +236,60 @@ func TestOpenAIGatewayService_OAuthPassthrough_StreamKeepsToolNameAndBodyNormali
 	require.NotContains(t, body, "\"name\":\"edit\"")
 }
 
+func TestOpenAIGatewayService_OAuthPassthrough_CompactUsesJSONAndKeepsNonStreaming(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses/compact", bytes.NewReader(nil))
+	c.Request.Header.Set("User-Agent", "codex_cli_rs/0.1.0")
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	originalBody := []byte(`{"model":"gpt-5.1-codex","stream":true,"store":true,"instructions":"local-test-instructions","input":[{"type":"text","text":"compact me"}]}`)
+
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"application/json"}, "x-request-id": []string{"rid-compact"}},
+		Body:       io.NopCloser(strings.NewReader(`{"id":"cmp_123","usage":{"input_tokens":11,"output_tokens":22}}`)),
+	}
+	upstream := &httpUpstreamRecorder{resp: resp}
+
+	svc := &OpenAIGatewayService{
+		cfg:          &config.Config{Gateway: config.GatewayConfig{ForceCodexCLI: false}},
+		httpUpstream: upstream,
+	}
+
+	account := &Account{
+		ID:             123,
+		Name:           "acc",
+		Platform:       PlatformOpenAI,
+		Type:           AccountTypeOAuth,
+		Concurrency:    1,
+		Credentials:    map[string]any{"access_token": "oauth-token", "chatgpt_account_id": "chatgpt-acc"},
+		Extra:          map[string]any{"openai_passthrough": true},
+		Status:         StatusActive,
+		Schedulable:    true,
+		RateMultiplier: f64p(1),
+	}
+
+	result, err := svc.Forward(context.Background(), c, account, originalBody)
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.False(t, result.Stream)
+
+	require.False(t, gjson.GetBytes(upstream.lastBody, "store").Exists())
+	require.False(t, gjson.GetBytes(upstream.lastBody, "stream").Exists())
+	require.Equal(t, "gpt-5.1-codex", gjson.GetBytes(upstream.lastBody, "model").String())
+	require.Equal(t, "compact me", gjson.GetBytes(upstream.lastBody, "input.0.text").String())
+	require.Equal(t, "local-test-instructions", strings.TrimSpace(gjson.GetBytes(upstream.lastBody, "instructions").String()))
+	require.Equal(t, "application/json", upstream.lastReq.Header.Get("Accept"))
+	require.Equal(t, codexCLIVersion, upstream.lastReq.Header.Get("Version"))
+	require.NotEmpty(t, upstream.lastReq.Header.Get("Session_Id"))
+	require.Equal(t, "chatgpt.com", upstream.lastReq.Host)
+	require.Equal(t, "chatgpt-acc", upstream.lastReq.Header.Get("chatgpt-account-id"))
+	require.Contains(t, rec.Body.String(), `"id":"cmp_123"`)
+}
+
 func TestOpenAIGatewayService_OAuthPassthrough_CodexMissingInstructionsRejectedBeforeUpstream(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	logSink, restore := captureStructuredLog(t)
diff --git a/backend/internal/web/embed_on.go b/backend/internal/web/embed_on.go
index f7ba5c9e..41ce4d48 100644
--- a/backend/internal/web/embed_on.go
+++ b/backend/internal/web/embed_on.go
@@ -83,14 +83,7 @@ func (s *FrontendServer) Middleware() gin.HandlerFunc {
 		path := c.Request.URL.Path
 
 		// Skip API routes
-		if strings.HasPrefix(path, "/api/") ||
-			strings.HasPrefix(path, "/v1/") ||
-			strings.HasPrefix(path, "/v1beta/") ||
-			strings.HasPrefix(path, "/sora/") ||
-			strings.HasPrefix(path, "/antigravity/") ||
-			strings.HasPrefix(path, "/setup/") ||
-			path == "/health" ||
-			path == "/responses" {
+		if shouldBypassEmbeddedFrontend(path) {
 			c.Next()
 			return
 		}
@@ -207,14 +200,7 @@ func ServeEmbeddedFrontend() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		path := c.Request.URL.Path
 
-		if strings.HasPrefix(path, "/api/") ||
-			strings.HasPrefix(path, "/v1/") ||
-			strings.HasPrefix(path, "/v1beta/") ||
-			strings.HasPrefix(path, "/sora/") ||
-			strings.HasPrefix(path, "/antigravity/") ||
-			strings.HasPrefix(path, "/setup/") ||
-			path == "/health" ||
-			path == "/responses" {
+		if shouldBypassEmbeddedFrontend(path) {
 			c.Next()
 			return
 		}
@@ -235,6 +221,19 @@ func ServeEmbeddedFrontend() gin.HandlerFunc {
 	}
 }
 
+func shouldBypassEmbeddedFrontend(path string) bool {
+	trimmed := strings.TrimSpace(path)
+	return strings.HasPrefix(trimmed, "/api/") ||
+		strings.HasPrefix(trimmed, "/v1/") ||
+		strings.HasPrefix(trimmed, "/v1beta/") ||
+		strings.HasPrefix(trimmed, "/sora/") ||
+		strings.HasPrefix(trimmed, "/antigravity/") ||
+		strings.HasPrefix(trimmed, "/setup/") ||
+		trimmed == "/health" ||
+		trimmed == "/responses" ||
+		strings.HasPrefix(trimmed, "/responses/")
+}
+
 func serveIndexHTML(c *gin.Context, fsys fs.FS) {
 	file, err := fsys.Open("index.html")
 	if err != nil {
diff --git a/backend/internal/web/embed_test.go b/backend/internal/web/embed_test.go
index e2cbcf15..f270b624 100644
--- a/backend/internal/web/embed_test.go
+++ b/backend/internal/web/embed_test.go
@@ -367,6 +367,7 @@ func TestFrontendServer_Middleware(t *testing.T) {
 			"/setup/init",
 			"/health",
 			"/responses",
+			"/responses/compact",
 		}
 
 		for _, path := range apiPaths {
@@ -388,6 +389,32 @@ func TestFrontendServer_Middleware(t *testing.T) {
 		}
 	})
 
+	t.Run("skips_responses_compact_post_routes", func(t *testing.T) {
+		provider := &mockSettingsProvider{
+			settings: map[string]string{"test": "value"},
+		}
+
+		server, err := NewFrontendServer(provider)
+		require.NoError(t, err)
+
+		router := gin.New()
+		router.Use(server.Middleware())
+		nextCalled := false
+		router.POST("/responses/compact", func(c *gin.Context) {
+			nextCalled = true
+			c.String(http.StatusOK, `{"ok":true}`)
+		})
+
+		w := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodPost, "/responses/compact", strings.NewReader(`{"model":"gpt-5"}`))
+		req.Header.Set("Content-Type", "application/json")
+		router.ServeHTTP(w, req)
+
+		assert.True(t, nextCalled, "next handler should be called for compact API route")
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.JSONEq(t, `{"ok":true}`, w.Body.String())
+	})
+
 	t.Run("serves_index_for_spa_routes", func(t *testing.T) {
 		provider := &mockSettingsProvider{
 			settings: map[string]string{"test": "value"},
@@ -543,6 +570,7 @@ func TestServeEmbeddedFrontend(t *testing.T) {
 			"/setup/init",
 			"/health",
 			"/responses",
+			"/responses/compact",
 		}
 
 		for _, path := range apiPaths {