feat: support native Seedance Ark video task API

backend/internal/handler/endpoint.go

@@ -29,6 +29,7 @@ const (
 	EndpointVideosEdits          = "/v1/videos/edits"
 	EndpointVideosExtensions     = "/v1/videos/extensions"
 	EndpointVideos               = "/v1/videos"
+	EndpointSeedanceTasks        = "/api/v3/contents/generations/tasks"
 	EndpointGeminiModels         = "/v1beta/models"
 )
 
@@ -81,6 +82,8 @@ const (
 func NormalizeInboundEndpoint(path string) string {
 	path = strings.TrimSpace(path)
 	switch {
+	case strings.Contains(path, "/contents/generations/tasks"):
+		return EndpointSeedanceTasks
 	case strings.Contains(path, EndpointResponsesInputTokens) || isResponsesInputTokensAliasPath(path):
 		return EndpointResponsesInputTokens
 	case strings.Contains(path, EndpointEmbeddings):

backend/internal/handler/grok_media.go

@@ -52,6 +52,12 @@ func (h *OpenAIGatewayHandler) GrokVideoContent(c *gin.Context) {
 }
 
 func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.GrokMediaEndpoint, requestID string) {
+	platform := service.PlatformGrok
+	noAccountCode, noAccountMessage := "grok_media_no_eligible_account", "No eligible Grok media accounts"
+	if endpoint.IsSeedance() {
+		platform = service.PlatformOpenAI
+		noAccountCode, noAccountMessage = "seedance_no_eligible_account", "No eligible Seedance accounts"
+	}
 	streamStarted := false
 	defer h.recoverResponsesPanic(c, &streamStarted)
 
@@ -99,6 +105,13 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 
 	contentType := c.GetHeader("Content-Type")
 	requestInfo := service.ParseGrokMediaRequest(contentType, body)
+	if endpoint == service.SeedanceEndpointCreate {
+		requestInfo, err = service.ParseSeedanceRequest(body)
+		if err != nil {
+			h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", err.Error())
+			return
+		}
+	}
 	requestModel := requestInfo.Model
 	routingModel := service.NormalizeGrokMediaModelForEndpoint(endpoint, requestModel, requestInfo.HasInputImage())
 	if endpoint.IsGenerationRequest() && strings.TrimSpace(requestModel) == "" {
@@ -215,8 +228,8 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 		var selection *service.AccountSelectionResult
 		var scheduleDecision service.OpenAIAccountScheduleDecision
 		if boundLookupAccountID > 0 {
-			selection, scheduleDecision, err = h.gatewayService.SelectGrokMediaVideoRequestAccount(
-				requestCtx, apiKey.GroupID, sessionHash, boundLookupAccountID, routingModel,
+			selection, scheduleDecision, err = h.gatewayService.SelectMediaVideoRequestAccount(
+				requestCtx, apiKey.GroupID, sessionHash, boundLookupAccountID, routingModel, platform,
 			)
 		} else {
 			selection, scheduleDecision, err = h.gatewayService.SelectAccountWithSchedulerForCapability(
@@ -231,7 +244,7 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 				false,
 				false,
 				false,
-				service.PlatformGrok,
+				platform,
 			)
 		}
 		// Own an eagerly acquired slot before any rejection or eligibility probe.
@@ -256,11 +269,11 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 			if endpoint.IsGenerationRequest() && errors.Is(err, service.ErrNoAvailableAccounts) &&
 				(len(failedAccountIDs) == 0 || (mediaEligibilityRejected && lastFailoverErr == nil)) {
 				markOpsRoutingCapacityLimitedIfNoAvailable(c, err)
-				h.errorResponse(c, http.StatusServiceUnavailable, "grok_media_no_eligible_account", "No eligible Grok media accounts")
+				h.errorResponse(c, http.StatusServiceUnavailable, noAccountCode, noAccountMessage)
 				return
 			}
 			if len(failedAccountIDs) == 0 {
-				cls := classifyNoAccountErrorFromGin(c, h.gatewayService, apiKey, requestModel, routingModel, service.PlatformGrok)
+				cls := classifyNoAccountErrorFromGin(c, h.gatewayService, apiKey, requestModel, routingModel, platform)
 				if !cls.ModelNotFound {
 					markOpsRoutingCapacityLimitedIfNoAvailable(c, err)
 				}
@@ -277,10 +290,10 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 		if selection == nil || selection.Account == nil {
 			if endpoint.IsGenerationRequest() {
 				markOpsRoutingCapacityLimited(c)
-				h.errorResponse(c, http.StatusServiceUnavailable, "grok_media_no_eligible_account", "No eligible Grok media accounts")
+				h.errorResponse(c, http.StatusServiceUnavailable, noAccountCode, noAccountMessage)
 				return
 			}
-			cls := classifyNoAccountErrorFromGin(c, h.gatewayService, apiKey, requestModel, routingModel, service.PlatformGrok)
+			cls := classifyNoAccountErrorFromGin(c, h.gatewayService, apiKey, requestModel, routingModel, platform)
 			if !cls.ModelNotFound {
 				markOpsRoutingCapacityLimited(c)
 			}
@@ -309,7 +322,7 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 		)
 
 		account := selection.Account
-		if endpoint.IsGenerationRequest() {
+		if endpoint.IsGenerationRequest() && !endpoint.IsSeedance() {
 			eligible, eligibilityReason, eligibilityErr := h.ensureGrokMediaAccountEligibility(requestCtx, account)
 			if !eligible {
 				releaseAccount()
@@ -360,6 +373,9 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 		writerSizeBeforeForward := c.Writer.Size()
 		result, err := func() (*service.OpenAIForwardResult, error) {
 			defer releaseAccount()
+			if endpoint.IsSeedance() {
+				return h.gatewayService.ForwardSeedance(requestCtx, c, account, endpoint, requestID, body)
+			}
 			return h.gatewayService.ForwardGrokMedia(requestCtx, c, account, endpoint, requestID, body, contentType)
 		}()
 
@@ -490,7 +506,11 @@ func (h *OpenAIGatewayHandler) handleGrokMedia(c *gin.Context, endpoint service.
 		}
 		// Status poll OR content download can observe official done+video.url.
 		// Both paths share the same claim key so the customer is charged once.
-		if endpoint == service.GrokMediaEndpointVideoStatus || endpoint == service.GrokMediaEndpointVideoContent {
+		if endpoint == service.SeedanceEndpointStatus {
+			if billResult := prepareSeedanceCompletionBilling(requestCtx, h, apiKey, subject, requestID, result); billResult != nil {
+				recordGrokMediaUsage(c, h, reqLog, apiKey, subject, subscription, account, billResult, billResult.Model, body, requestID)
+			}
+		} else if endpoint == service.GrokMediaEndpointVideoStatus || endpoint == service.GrokMediaEndpointVideoContent {
 			taskID := strings.TrimSpace(requestID)
 			if billResult := prepareGrokVideoCompletionBilling(requestCtx, h, reqLog, apiKey, subject, taskID, result); billResult != nil {
 				recordGrokMediaUsage(c, h, reqLog, apiKey, subject, subscription, account, billResult, billResult.Model, body, taskID)
@@ -521,6 +541,9 @@ func (h *OpenAIGatewayHandler) ensureGrokMediaAccountEligibility(ctx context.Con
 }
 
 func grokMediaRequiredCapability(endpoint service.GrokMediaEndpoint) service.OpenAIEndpointCapability {
+	if endpoint.IsSeedance() {
+		return service.OpenAIEndpointCapabilitySeedance
+	}
 	if endpoint.IsGenerationRequest() {
 		return service.OpenAIEndpointCapabilityGrokMediaGeneration
 	}
@@ -539,7 +562,7 @@ func grokMediaScheduleModel(account *service.Account, routingModel string, resul
 
 func isGrokVideoCreateEndpoint(endpoint service.GrokMediaEndpoint) bool {
 	switch endpoint {
-	case service.GrokMediaEndpointVideosGenerations,
+	case service.SeedanceEndpointCreate, service.GrokMediaEndpointVideosGenerations,
 		service.GrokMediaEndpointVideosEdits,
 		service.GrokMediaEndpointVideosExtensions:
 		return true
@@ -712,7 +735,7 @@ func recordGrokMediaUsage(
 	}
 	// Async video: force durable task request id and release claim if billing fails.
 	videoTaskID := ""
-	if result != nil && result.VideoCount > 0 {
+	if result != nil && (result.VideoCount > 0 || strings.HasPrefix(result.ResponseID, "seedance:")) {
 		videoTaskID = strings.TrimSpace(firstNonEmptyString(requestID, result.ResponseID))
 		if stable := service.StableGrokVideoBillingRequestID(firstNonEmptyString(result.ResponseID, requestID)); stable != "" {
 			result.RequestID = stable

backend/internal/handler/grok_media_slots_test.go

@@ -120,10 +120,22 @@ func (s *grokMediaSlotsCache) assertReleased(t *testing.T) {
 
 type grokMediaSlotBindings struct {
 	testutil.StubGatewayCache
-	owner  int64
-	writes int
-	key    string
-	billed map[string]bool
+	owner   int64
+	writes  int
+	key     string
+	billed  map[string]bool
+	pending map[string][]byte
+}
+
+func (s *grokMediaSlotBindings) SetGrokVideoPendingBilling(_ context.Context, key string, body []byte, _ time.Duration) error {
+	if s.pending == nil {
+		s.pending = make(map[string][]byte)
+	}
+	s.pending[key] = append([]byte(nil), body...)
+	return nil
+}
+func (s *grokMediaSlotBindings) GetGrokVideoPendingBilling(_ context.Context, key string) ([]byte, error) {
+	return s.pending[key], nil
 }
 
 func (s *grokMediaSlotBindings) GetSessionAccountID(_ context.Context, groupID int64, key string) (int64, error) {
@@ -186,7 +198,7 @@ func (p grokMediaSlotProber) ProbeMediaEligibility(ctx context.Context, id int64
 	return p(ctx, id)
 }
 
-func newGrokMediaSlotHandler(t *testing.T, oauth, mismatch bool) (*OpenAIGatewayHandler, *grokMediaSlotsCache, *grokMediaSlotBindings, *grokMediaSlotUpstream) {
+func newGrokMediaSlotHandler(t *testing.T, oauth, mismatch bool, platforms ...string) (*OpenAIGatewayHandler, *grokMediaSlotsCache, *grokMediaSlotBindings, *grokMediaSlotUpstream) {
 	t.Helper()
 	gin.SetMode(gin.TestMode)
 	accounts := make([]service.Account, 3)
@@ -194,6 +206,11 @@ func newGrokMediaSlotHandler(t *testing.T, oauth, mismatch bool) (*OpenAIGateway
 		accounts[i] = service.Account{ID: int64(i + 1), Platform: service.PlatformGrok, Type: service.AccountTypeAPIKey,
 			Status: service.StatusActive, Schedulable: true, Concurrency: 50, Priority: i,
 			GroupIDs: []int64{24}, Credentials: map[string]any{"api_key": "test-key", "access_token": "test-token"}}
+		if len(platforms) > 0 {
+			accounts[i].Platform = platforms[0]
+			accounts[i].Credentials["base_url"] = "https://ark.cn-beijing.volces.com/api/v3"
+			accounts[i].Credentials["openai_capabilities"] = []string{"seedance"}
+		}
 		if oauth {
 			accounts[i].Type = service.AccountTypeOAuth
 			accounts[i].Credentials["refresh_token"] = "test-refresh"

backend/internal/handler/seedance.go

@@ -0,0 +1,63 @@
+package handler
+
+import (
+	"context"
+	"mime"
+	"net/http"
+	"time"
+
+	middleware "github.com/Wei-Shaw/sub2api/internal/server/middleware"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/gin-gonic/gin"
+)
+
+// SeedanceTasks exposes Ark's native asynchronous video task protocol.
+func (h *OpenAIGatewayHandler) SeedanceTasks(c *gin.Context) {
+	if c.Request.Method == http.MethodPost && c.GetHeader("Content-Type") != "" {
+		mediaType, _, err := mime.ParseMediaType(c.GetHeader("Content-Type"))
+		if err != nil || mediaType != "application/json" {
+			h.errorResponse(c, http.StatusUnsupportedMediaType, "invalid_request_error", "Seedance requires application/json")
+			return
+		}
+	}
+	key, ok := middleware.GetAPIKeyFromContext(c)
+	if !ok || key.Group == nil || (key.Group.Platform != service.PlatformOpenAI && key.Group.Platform != service.PlatformComposite) {
+		h.errorResponse(c, http.StatusForbidden, "permission_error", "Seedance requires an OpenAI or composite group")
+		return
+	}
+	endpoint := service.SeedanceEndpointCreate
+	setActualUpstreamEndpoint(c, EndpointSeedanceTasks)
+	taskID := ""
+	if c.Request.Method != http.MethodPost {
+		taskID = service.SeedanceTaskKey(c.Param("task_id"))
+		endpoint = service.SeedanceEndpointStatus
+		if c.Request.Method == http.MethodDelete {
+			endpoint = service.SeedanceEndpointDelete
+		}
+	}
+	h.handleGrokMedia(c, endpoint, taskID)
+}
+
+// Ark reports actual completion tokens. Never infer tokens from duration or use
+// Grok's per-second video tariff. Repeated polls share the durable task dedup key.
+func prepareSeedanceCompletionBilling(ctx context.Context, h *OpenAIGatewayHandler, key *service.APIKey, subject middleware.AuthSubject, taskID string, result *service.OpenAIForwardResult) *service.OpenAIForwardResult {
+	if result == nil || result.Usage.OutputTokens <= 0 {
+		return nil
+	}
+	pending, err := h.gatewayService.LoadGrokVideoPendingBilling(ctx, taskID, subject.UserID, key.ID)
+	if err != nil || pending == nil {
+		return nil
+	}
+	claimed, err := h.gatewayService.ClaimGrokVideoBilling(ctx, taskID, subject.UserID, key.ID)
+	if err != nil || !claimed {
+		return nil
+	}
+	merged := *result
+	merged.Model = pending.Model
+	merged.BillingModel = firstNonEmptyString(pending.BillingModel, pending.Model)
+	merged.UpstreamModel = firstNonEmptyString(pending.UpstreamModel, result.UpstreamModel)
+	merged.RequestID = service.StableGrokVideoBillingRequestID(taskID)
+	merged.ResponseID = taskID
+	merged.Duration = service.GrokVideoE2EDuration(pending.CreatedAt, time.Now())
+	return &merged
+}

backend/internal/handler/seedance_test.go

@@ -0,0 +1,97 @@
+//go:build unit
+
+package handler
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	middleware "github.com/Wei-Shaw/sub2api/internal/server/middleware"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSeedanceHandlerLifecycleAndOwnership(t *testing.T) {
+	h, slots, bindings, upstream := newGrokMediaSlotHandler(t, false, false, service.PlatformOpenAI)
+	var owner int64
+	upstream.call = func(req *http.Request, id int64) (*http.Response, error) {
+		body := `{"id":"task-ark","status":"queued"}`
+		if req.Method == http.MethodPost {
+			owner = id
+		} else {
+			require.Equal(t, owner, id)
+		}
+		return &http.Response{StatusCode: 200, Header: http.Header{"Content-Type": []string{"application/json"}}, Body: io.NopCloser(strings.NewReader(body))}, nil
+	}
+	newContext := func(method string) (*gin.Context, *httptest.ResponseRecorder) {
+		c, w := grokMediaSlotContext(context.Background(), method == http.MethodPost)
+		key, _ := middleware.GetAPIKeyFromContext(c)
+		key.Group.Platform = service.PlatformOpenAI
+		body := ""
+		if method == http.MethodPost {
+			body = `{"model":"doubao-seedance","content":[{"type":"text","text":"waves"}]}`
+		}
+		c.Request = httptest.NewRequest(method, "/api/v3/contents/generations/tasks", strings.NewReader(body))
+		c.Params = gin.Params{{Key: "task_id", Value: "task-ark"}}
+		return c, w
+	}
+	c, w := newContext(http.MethodPost)
+	h.SeedanceTasks(c)
+	require.Equal(t, 200, w.Code, w.Body.String())
+	require.Positive(t, owner)
+	require.Len(t, bindings.pending, 1)
+	slots.assertReleased(t)
+	for _, method := range []string{http.MethodGet, http.MethodDelete} {
+		c, w = newContext(method)
+		h.SeedanceTasks(c)
+		require.Equal(t, 200, w.Code, w.Body.String())
+		slots.assertReleased(t)
+	}
+	for _, other := range []string{"user", "key", "group", "task", "provider"} {
+		c, w = newContext(http.MethodGet)
+		key, _ := middleware.GetAPIKeyFromContext(c)
+		switch other {
+		case "user":
+			c.Set(string(middleware.ContextKeyUser), middleware.AuthSubject{UserID: 11, Concurrency: 5})
+		case "key":
+			key.ID = 21
+		case "group":
+			group := int64(25)
+			key.GroupID = &group
+		case "task":
+			c.Params = gin.Params{{Key: "task_id", Value: "other"}}
+		case "provider":
+			c.Params = gin.Params{{Key: "request_id", Value: "task-ark"}}
+		}
+		before := upstream.calls
+		if other == "provider" {
+			h.GrokVideoStatus(c)
+		} else {
+			h.SeedanceTasks(c)
+		}
+		require.Equal(t, 404, w.Code, other+": "+w.Body.String())
+		require.Equal(t, before, upstream.calls)
+		slots.assertReleased(t)
+	}
+	c, _ = newContext(http.MethodGet)
+	key, _ := middleware.GetAPIKeyFromContext(c)
+	subject, _ := middleware.GetAuthSubjectFromContext(c)
+	result := &service.OpenAIForwardResult{Usage: service.OpenAIUsage{OutputTokens: 12345}, ResponseID: "seedance:task-ark"}
+	for i := range 20 {
+		billed := prepareSeedanceCompletionBilling(context.Background(), h, key, subject, result.ResponseID, result)
+		if i == 0 {
+			require.NotNil(t, billed)
+			require.Equal(t, "doubao-seedance", billed.BillingModel)
+			require.Equal(t, 12345, billed.Usage.OutputTokens)
+			require.Zero(t, billed.VideoCount)
+		} else {
+			require.Nil(t, billed)
+		}
+	}
+	require.Len(t, bindings.billed, 1)
+}

backend/internal/server/routes/gateway.go

@@ -368,6 +368,11 @@ func RegisterGatewayRoutes(
 	rootRoute := func(method, path string, limit gin.HandlerFunc, handler gin.HandlerFunc) {
 		r.Handle(method, path, limit, clientRequestID, opsErrorLogger, endpointNorm, gin.HandlerFunc(apiKeyAuth), groupModelAllowlist, compositeTarget, requireGroupAnthropic, handler)
 	}
+	for _, prefix := range []string{"/api/v3", "/v3", "/v1", ""} {
+		rootRoute(http.MethodPost, prefix+"/contents/generations/tasks", bodyLimit, h.OpenAIGateway.SeedanceTasks)
+		rootRoute(http.MethodGet, prefix+"/contents/generations/tasks/:task_id", bodyLimit, h.OpenAIGateway.SeedanceTasks)
+		rootRoute(http.MethodDelete, prefix+"/contents/generations/tasks/:task_id", bodyLimit, h.OpenAIGateway.SeedanceTasks)
+	}
 	rootRoute(http.MethodPost, "/responses", bodyLimit, responsesHandler)
 	rootRoute(http.MethodPost, "/responses/*subpath", bodyLimit, guardResponsesSubpath(responsesHandler))
 	rootRoute(http.MethodPost, "/alpha/search", textBodyLimit, h.OpenAIGateway.AlphaSearch)

backend/internal/server/routes/gateway_model_allowlist_test.go

@@ -157,6 +157,10 @@ func TestGatewayRoutesGroupModelAllowlistCoversRootAliasRoutes(t *testing.T) {
 		{http.MethodPost, "/v1/embeddings", `{"model":"gpt-4.1","input":"hi"}`},
 		{http.MethodPost, "/v1/images/generations", `{"model":"gpt-4.1"}`},
 		{http.MethodPost, "/v1/videos/generations", `{"model":"gpt-4.1"}`},
+		{http.MethodPost, "/api/v3/contents/generations/tasks", `{"model":"gpt-4.1","content":[{"type":"text","text":"waves"}]}`},
+		{http.MethodPost, "/v3/contents/generations/tasks", `{"model":"gpt-4.1","content":[{"type":"text","text":"waves"}]}`},
+		{http.MethodPost, "/v1/contents/generations/tasks", `{"model":"gpt-4.1","content":[{"type":"text","text":"waves"}]}`},
+		{http.MethodPost, "/contents/generations/tasks", `{"model":"gpt-4.1","content":[{"type":"text","text":"waves"}]}`},
 		{http.MethodPost, "/v1/live", `{"session":{"model":"gpt-4.1"},"sdp":"v=0"}`},
 		{http.MethodPost, "/backend-api/codex/responses", `{"model":"gpt-4.1"}`},
 		{http.MethodPost, "/backend-api/codex/realtime/calls", `{"session":{"model":"gpt-4.1"},"sdp":"v=0"}`},

backend/internal/server/routes/seedance_test.go

@@ -0,0 +1,34 @@
+package routes
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSeedanceNativeRoutes(t *testing.T) {
+	router := newGatewayRoutesTestRouter()
+	for _, prefix := range []string{"/api/v3", "/v3", "/v1", ""} {
+		for _, method := range []string{http.MethodPost, http.MethodGet, http.MethodDelete} {
+			path := prefix + "/contents/generations/tasks"
+			if method != http.MethodPost {
+				path += "/task-1"
+			}
+			w := httptest.NewRecorder()
+			router.ServeHTTP(w, httptest.NewRequest(method, path, strings.NewReader(`{"model":"seedance","content":[{"type":"text","text":"waves"}]}`)))
+			require.NotEqual(t, http.StatusNotFound, w.Code, method+" "+path)
+		}
+	}
+}
+
+func TestSeedanceRejectsOtherPlatforms(t *testing.T) {
+	for _, platform := range []string{service.PlatformGrok, service.PlatformAnthropic, service.PlatformGemini} {
+		w := httptest.NewRecorder()
+		newGatewayRoutesTestRouter(platform).ServeHTTP(w, httptest.NewRequest(http.MethodPost, "/api/v3/contents/generations/tasks", strings.NewReader(`{"model":"seedance","content":[{}]}`)))
+		require.Equal(t, http.StatusForbidden, w.Code)
+	}
+}

backend/internal/service/account.go

@@ -1828,6 +1828,11 @@ func (a *Account) SupportsOpenAIEndpointCapability(capability OpenAIEndpointCapa
 	if a == nil {
 		return false
 	}
+	if capability == OpenAIEndpointCapabilitySeedance {
+		configured, _ := a.openAIEndpointCapabilitySet()
+		return configured["seedance"] && a.Platform == PlatformOpenAI && a.Type == AccountTypeAPIKey &&
+			strings.TrimSpace(a.GetCredential("base_url")) != ""
+	}
 	if capability == "" {
 		return true
 	}

backend/internal/service/grok_media.go

@@ -41,10 +41,13 @@ func (e GrokMediaEndpoint) RequiresRequestBody() bool {
 }
 
 func (e GrokMediaEndpoint) IsVideoLookupRequest() bool {
-	return e == GrokMediaEndpointVideoStatus || e == GrokMediaEndpointVideoContent
+	return e == GrokMediaEndpointVideoStatus || e == GrokMediaEndpointVideoContent || e == SeedanceEndpointStatus || e == SeedanceEndpointDelete
 }
 
 func (e GrokMediaEndpoint) IsGenerationRequest() bool {
+	if e == SeedanceEndpointCreate {
+		return true
+	}
 	switch e {
 	case GrokMediaEndpointImagesGenerations, GrokMediaEndpointImagesEdits, GrokMediaEndpointVideosGenerations, GrokMediaEndpointVideosEdits, GrokMediaEndpointVideosExtensions:
 		return true
@@ -337,6 +340,12 @@ func (s *OpenAIGatewayService) ResolveGrokMediaVideoRequestAccount(
 // the ownership key; video lookups must neither escape nor refresh that key.
 func (s *OpenAIGatewayService) SelectGrokMediaVideoRequestAccount(
 	ctx context.Context, groupID *int64, sessionHash string, accountID int64, requestedModel string,
+) (*AccountSelectionResult, OpenAIAccountScheduleDecision, error) {
+	return s.SelectMediaVideoRequestAccount(ctx, groupID, sessionHash, accountID, requestedModel, PlatformGrok)
+}
+
+func (s *OpenAIGatewayService) SelectMediaVideoRequestAccount(
+	ctx context.Context, groupID *int64, sessionHash string, accountID int64, requestedModel, platform string,
 ) (*AccountSelectionResult, OpenAIAccountScheduleDecision, error) {
 	decision := OpenAIAccountScheduleDecision{Layer: openAIAccountScheduleLayerSessionSticky}
 	if accountID <= 0 || strings.TrimSpace(sessionHash) == "" {
@@ -345,7 +354,7 @@ func (s *OpenAIGatewayService) SelectGrokMediaVideoRequestAccount(
 	ctx = s.withOpenAIGroupPrivacyRequirement(WithOpenAIProfitControlSuppressed(ctx), groupID)
 	scheduler := &defaultOpenAIAccountScheduler{service: s}
 	selection, _, err := scheduler.selectBySessionHash(ctx, OpenAIAccountScheduleRequest{
-		GroupID: groupID, Platform: PlatformGrok, SessionHash: sessionHash,
+		GroupID: groupID, Platform: platform, SessionHash: sessionHash,
 		StickyAccountID: accountID, PreserveStickyBinding: true, DisableStickyEscape: true,
 		RequestedModel: requestedModel, RequiredTransport: OpenAIUpstreamTransportHTTPSSE,
 		RequirePrivacySet: s.openAIGroupRequiresPrivacySet(ctx, groupID),

backend/internal/service/seedance.go

@@ -0,0 +1,154 @@
+package service
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+const (
+	SeedanceEndpointCreate           GrokMediaEndpoint        = "seedance_create"
+	SeedanceEndpointStatus           GrokMediaEndpoint        = "seedance_status"
+	SeedanceEndpointDelete           GrokMediaEndpoint        = "seedance_delete"
+	OpenAIEndpointCapabilitySeedance OpenAIEndpointCapability = "seedance"
+)
+
+func (e GrokMediaEndpoint) IsSeedance() bool {
+	return e == SeedanceEndpointCreate || e == SeedanceEndpointStatus || e == SeedanceEndpointDelete
+}
+
+// SeedanceTaskKey isolates ownership and billing keys from other video providers.
+func SeedanceTaskKey(id string) string { return "seedance:" + strings.TrimSpace(id) }
+
+func ParseSeedanceRequest(body []byte) (GrokMediaRequestInfo, error) {
+	var info GrokMediaRequestInfo
+	if !gjson.ValidBytes(body) || !gjson.ParseBytes(body).IsObject() {
+		return info, fmt.Errorf("request body must be a JSON object")
+	}
+	model := gjson.GetBytes(body, "model")
+	if model.Type != gjson.String || strings.TrimSpace(model.String()) == "" {
+		return info, fmt.Errorf("model is required")
+	}
+	content := gjson.GetBytes(body, "content")
+	if !content.IsArray() || len(content.Array()) == 0 {
+		return info, fmt.Errorf("content must be a non-empty array")
+	}
+	info.Model = strings.TrimSpace(model.String())
+	var texts []string
+	for _, item := range content.Array() {
+		switch item.Get("type").String() {
+		case "text":
+			texts = append(texts, item.Get("text").String())
+		case "image_url":
+			info.InputImageURLs = append(info.InputImageURLs, item.Get("image_url.url").String())
+		}
+	}
+	info.Prompt = strings.Join(texts, "\n")
+	return info, nil
+}
+
+func buildSeedanceURL(base string, endpoint GrokMediaEndpoint, taskID string) (string, error) {
+	base = strings.TrimRight(base, "/")
+	// Accept an origin, a proxy prefix, or the full Ark API base.
+	if !strings.HasSuffix(base, "/api/v3") && !strings.HasSuffix(base, "/v3") {
+		base += "/api/v3"
+	}
+	base += "/contents/generations/tasks"
+	if endpoint != SeedanceEndpointCreate {
+		if err := validateUpstreamPathSegment("Seedance task ID", taskID); err != nil || strings.TrimSpace(taskID) == "" {
+			return "", fmt.Errorf("invalid Seedance task ID")
+		}
+		base += "/" + taskID
+	}
+	return base, nil
+}
+
+// ForwardSeedance preserves the Ark protocol, including multimodal content and
+// future fields. Only model is rewritten using the account's configured mapping.
+func (s *OpenAIGatewayService) ForwardSeedance(ctx context.Context, c *gin.Context, account *Account, endpoint GrokMediaEndpoint, taskID string, body []byte) (*OpenAIForwardResult, error) {
+	if !account.SupportsOpenAIEndpointCapability(OpenAIEndpointCapabilitySeedance) || !endpoint.IsSeedance() {
+		return nil, fmt.Errorf("Seedance requires an OpenAI API key account with a custom base URL")
+	}
+	base, err := s.validateUpstreamBaseURL(account.GetCredential("base_url"))
+	if err != nil {
+		return nil, err
+	}
+	target, err := buildSeedanceURL(base, endpoint, strings.TrimPrefix(taskID, "seedance:"))
+	if err != nil {
+		return nil, err
+	}
+	model, upstreamModel := "", ""
+	method := http.MethodGet
+	if endpoint == SeedanceEndpointCreate {
+		info, parseErr := ParseSeedanceRequest(body)
+		if parseErr != nil {
+			return nil, parseErr
+		}
+		model = info.Model
+		upstreamModel = account.GetMappedModel(model)
+		body, err = sjson.SetBytes(body, "model", upstreamModel)
+		if err != nil {
+			return nil, err
+		}
+		method = http.MethodPost
+	} else if endpoint == SeedanceEndpointDelete {
+		method = http.MethodDelete
+	}
+	token := strings.TrimSpace(account.GetCredential("api_key"))
+	if token == "" {
+		return nil, fmt.Errorf("Seedance account missing api_key")
+	}
+	started := time.Now()
+	req, err := http.NewRequestWithContext(ctx, method, target, bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "application/json")
+	account.ApplyHeaderOverrides(req.Header)
+	proxy := ""
+	if account.ProxyID != nil && account.Proxy != nil {
+		proxy = account.Proxy.URL()
+	}
+	resp, err := s.httpUpstream.Do(req, proxy, account.ID, account.Concurrency)
+	SetOpsLatencyMs(c, OpsUpstreamLatencyMsKey, time.Since(started).Milliseconds())
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	responseBody, err := ReadUpstreamResponseBody(resp.Body, s.cfg, c, openAITooLargeError)
+	if err != nil {
+		return nil, err
+	}
+	// Do not retry ambiguous asynchronous creates: the upstream may already have
+	// accepted a billable job. Preserve native error codes and response bodies.
+	if resp.StatusCode >= 300 {
+		writeGrokMediaResponse(c, resp, responseBody, s.responseHeaderFilter)
+		return nil, fmt.Errorf("Seedance upstream status %d", resp.StatusCode)
+	}
+	result := &OpenAIForwardResult{Model: model, BillingModel: model, UpstreamModel: upstreamModel, Duration: time.Since(started), ResponseHeaders: resp.Header.Clone()}
+	if endpoint == SeedanceEndpointCreate {
+		id := strings.TrimSpace(gjson.GetBytes(responseBody, "id").String())
+		if id == "" {
+			return nil, fmt.Errorf("Seedance create response missing task ID")
+		}
+		result.ResponseID = SeedanceTaskKey(id)
+	}
+	if endpoint == SeedanceEndpointStatus {
+		result.ResponseID = taskID
+		result.UpstreamModel = gjson.GetBytes(responseBody, "model").String()
+		if gjson.GetBytes(responseBody, "status").String() == "succeeded" {
+			result.Usage.OutputTokens = max(0, int(gjson.GetBytes(responseBody, "usage.completion_tokens").Int()))
+		}
+	}
+	writeGrokMediaResponse(c, resp, responseBody, s.responseHeaderFilter)
+	return result, nil
+}

backend/internal/service/seedance_test.go

@@ -0,0 +1,112 @@
+//go:build unit
+
+package service
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/tidwall/gjson"
+)
+
+func seedanceTestAccount() *Account {
+	return &Account{ID: 9, Platform: PlatformOpenAI, Type: AccountTypeAPIKey, Credentials: map[string]any{
+		"api_key": "ark-secret", "base_url": "https://ark.cn-beijing.volces.com/api/v3",
+		"openai_capabilities": []string{"seedance"},
+		"model_mapping":       map[string]any{"video": "ep-seedance"},
+	}}
+}
+
+func TestSeedanceNativeForwarding(t *testing.T) {
+	body := []byte(`{"model":"video","content":[{"type":"text","text":"waves"},{"type":"image_url","image_url":{"url":"https://example.com/first.png"},"role":"first_frame"},{"type":"audio_url","audio_url":{"url":"https://example.com/audio.mp3"}}],"duration":-1,"generate_audio":true,"future_field":{"keep":true}}`)
+	upstream := &grokMediaContentUpstreamStub{response: grokMediaContentStatusResponse(`{"id":"task-1"}`)}
+	svc := &OpenAIGatewayService{httpUpstream: upstream}
+	c, w := grokMediaContentTestContext(http.MethodPost, "/api/v3/contents/generations/tasks", nil)
+	result, err := svc.ForwardSeedance(context.Background(), c, seedanceTestAccount(), SeedanceEndpointCreate, "", body)
+	require.NoError(t, err)
+	require.JSONEq(t, `{"id":"task-1"}`, w.Body.String())
+	require.Equal(t, "seedance:task-1", result.ResponseID)
+	require.Zero(t, result.Usage.OutputTokens)
+	require.Equal(t, "video", result.BillingModel)
+	require.Equal(t, "ep-seedance", result.UpstreamModel)
+	require.Equal(t, "https://ark.cn-beijing.volces.com/api/v3/contents/generations/tasks", upstream.request.URL.String())
+	require.Equal(t, "Bearer ark-secret", upstream.request.Header.Get("Authorization"))
+	forwarded, err := io.ReadAll(upstream.request.Body)
+	require.NoError(t, err)
+	require.Equal(t, "ep-seedance", gjson.GetBytes(forwarded, "model").String())
+	for _, field := range []string{"content", "duration", "generate_audio", "future_field"} {
+		require.Equal(t, gjson.GetBytes(body, field).Raw, gjson.GetBytes(forwarded, field).Raw)
+	}
+}
+
+func TestSeedanceStatusAndDelete(t *testing.T) {
+	for _, status := range []string{"queued", "running", "failed", "cancelled", "expired", "succeeded"} {
+		t.Run(status, func(t *testing.T) {
+			body := `{"id":"task-1","status":"` + status + `","model":"ep-seedance","content":{"video_url":"https://cdn.example/video.mp4"},"usage":{"completion_tokens":12345}}`
+			upstream := &grokMediaContentUpstreamStub{response: grokMediaContentStatusResponse(body)}
+			svc := &OpenAIGatewayService{httpUpstream: upstream}
+			c, w := grokMediaContentTestContext(http.MethodGet, "/api/v3/contents/generations/tasks/task-1", nil)
+			result, err := svc.ForwardSeedance(context.Background(), c, seedanceTestAccount(), SeedanceEndpointStatus, "seedance:task-1", nil)
+			require.NoError(t, err)
+			require.JSONEq(t, body, w.Body.String())
+			require.Equal(t, "/api/v3/contents/generations/tasks/task-1", upstream.request.URL.Path)
+			if status == "succeeded" {
+				require.Equal(t, 12345, result.Usage.OutputTokens)
+			} else {
+				require.Zero(t, result.Usage.OutputTokens)
+			}
+			require.Zero(t, result.VideoCount, "must use token billing, not Grok seconds")
+		})
+	}
+	upstream := &grokMediaContentUpstreamStub{response: grokMediaContentStatusResponse("")}
+	upstream.response.StatusCode = http.StatusNoContent
+	svc := &OpenAIGatewayService{httpUpstream: upstream}
+	c, w := grokMediaContentTestContext(http.MethodDelete, "/api/v3/contents/generations/tasks/task-1", nil)
+	_, err := svc.ForwardSeedance(context.Background(), c, seedanceTestAccount(), SeedanceEndpointDelete, "seedance:task-1", nil)
+	require.NoError(t, err)
+	require.Equal(t, http.MethodDelete, upstream.request.Method)
+	require.Equal(t, http.StatusNoContent, w.Code)
+}
+
+func TestSeedanceValidationAndCapability(t *testing.T) {
+	for _, body := range []string{`{`, `[]`, `{}`, `{"model":12,"content":[{}]}`, `{"model":"x","content":[]}`} {
+		_, err := ParseSeedanceRequest([]byte(body))
+		require.Error(t, err)
+	}
+	info, err := ParseSeedanceRequest([]byte(`{"model":"x","content":[{"type":"text","text":"first"},{"type":"text","text":"second"},{"type":"image_url","image_url":{"url":"https://example.com/a.png"}}]}`))
+	require.NoError(t, err)
+	require.Contains(t, string(info.ModerationBody()), "first")
+	require.Contains(t, string(info.ModerationBody()), "second")
+	require.Contains(t, string(info.ModerationBody()), "https://example.com/a.png")
+	for _, id := range []string{"", "..", "a/b", "a?b", "a#b", "%2e%2e"} {
+		_, err := buildSeedanceURL("https://example.com", SeedanceEndpointStatus, id)
+		require.Error(t, err, id)
+	}
+	for _, base := range []string{"https://example.com", "https://example.com/api/v3/", "https://example.com/v3"} {
+		url, err := buildSeedanceURL(base, SeedanceEndpointCreate, "")
+		require.NoError(t, err)
+		require.NotContains(t, url, "/v3/api/v3")
+	}
+	a := seedanceTestAccount()
+	require.True(t, a.SupportsOpenAIEndpointCapability(OpenAIEndpointCapabilitySeedance))
+	a.Type = AccountTypeOAuth
+	require.False(t, a.SupportsOpenAIEndpointCapability(OpenAIEndpointCapabilitySeedance))
+	a.Type = AccountTypeAPIKey
+	delete(a.Credentials, "openai_capabilities")
+	require.False(t, a.SupportsOpenAIEndpointCapability(OpenAIEndpointCapabilitySeedance))
+}
+
+func TestSeedancePreservesUpstreamErrorsWithoutRetry(t *testing.T) {
+	upstream := &grokMediaContentUpstreamStub{response: grokMediaContentStatusResponse(`{"error":{"code":"QuotaExceeded","message":"quota exhausted"}}`)}
+	upstream.response.StatusCode = 429
+	svc := &OpenAIGatewayService{httpUpstream: upstream}
+	c, w := grokMediaContentTestContext(http.MethodPost, "/api/v3/contents/generations/tasks", nil)
+	_, err := svc.ForwardSeedance(context.Background(), c, seedanceTestAccount(), SeedanceEndpointCreate, "", []byte(`{"model":"video","content":[{"type":"text","text":"waves"}]}`))
+	require.Error(t, err)
+	require.Equal(t, 429, w.Code)
+	require.Contains(t, w.Body.String(), "QuotaExceeded")
+	require.Len(t, upstream.requests, 1)
+}

docs/seedance-api.md

@@ -0,0 +1,45 @@
+# Seedance 原生 API
+
+支持火山方舟 Ark 的异步视频任务协议，无需把 `content[]` 转换成 OpenAI `messages` 或 Grok `prompt`。
+
+## 配置
+
+1. 创建 OpenAI 平台的 **API Key** 账号，填写 Ark API Key，Base URL 使用 `https://ark.cn-beijing.volces.com/api/v3`。兼容服务可填写自己的 `/api/v3` 或 `/v3` Base URL。
+2. 在账号的端点能力中勾选 **Seedance (Ark)**。默认不启用，避免请求误调度到其他 OpenAI 账号。支持创建、编辑与批量编辑。
+3. 将账号加入 OpenAI 分组并启用分组的「允许图片生成」媒体权限；合成分组也可路由到这些账号。
+4. 配置模型映射，例如将公开模型名 `seedance-video` 映射到实际 `doubao-seedance-*` 模型或 `ep-*` 推理接入点。配置对应模型的输出 token 价格；本接口不使用 Grok 的按秒视频价格。
+
+## 调用
+
+```bash
+curl "$SUB2API_BASE_URL/api/v3/contents/generations/tasks" \
+  -H "Authorization: Bearer $SUB2API_KEY" \
+  -H 'Content-Type: application/json' \
+  -d '{
+    "model": "seedance-video",
+    "content": [{"type": "text", "text": "海浪轻轻拍打沙滩"}],
+    "duration": 5,
+    "resolution": "720p",
+    "ratio": "16:9",
+    "generate_audio": true
+  }'
+
+# 使用创建响应中的原生 id 查询，直至 succeeded / failed / cancelled 等终态。
+curl "$SUB2API_BASE_URL/api/v3/contents/generations/tasks/$TASK_ID" \
+  -H "Authorization: Bearer $SUB2API_KEY"
+
+curl -X DELETE "$SUB2API_BASE_URL/api/v3/contents/generations/tasks/$TASK_ID" \
+  -H "Authorization: Bearer $SUB2API_KEY"
+```
+
+亦支持 `/v3`、`/v1` 和无版本前缀别名。Ark SDK 的 Base URL 可改为 `$SUB2API_BASE_URL/api/v3`。文本、图片、视频、音频内容、角色及扩展参数原样传递，仅按账号配置改写模型名；响应保持上游原生格式。
+
+## 任务与计费
+
+- 查询和删除只能访问同一用户、同一 API Key、同一分组创建的任务，并始终使用原提交账号；不会转到其他账号查询。
+- 创建时不扣 token 用量。首次查询到 `succeeded` 后，根据上游 `usage.completion_tokens` 计费；重复查询由共享缓存声明和持久化用量去重共同保护。失败、排队及运行中的任务不计费。
+- Redis 保存任务绑定及创建时的模型快照，默认 24 小时。需保留 Redis 状态并在有效期内查询完成结果。当前不会后台轮询；只使用回调而不查询的任务不会自动结算。
+- 不开放上游的任务列表接口，防止共享账号的任务泄露给其他用户。删除遵循上游语义，不自动退款。
+- 异步创建的上游错误不自动重试，以免重复创建付费任务。
+
+协议依据：[火山官方 Go SDK](https://github.com/volcengine/volcengine-go-sdk/blob/master/service/arkruntime/model/content_generation.go)、[创建任务文档](https://www.volcengine.com/docs/82379/1520757)、[查询任务文档](https://www.volcengine.com/docs/82379/1521309)。

frontend/src/components/account/BulkEditAccountModal.vue

@@ -1786,7 +1786,8 @@ const openAIEndpointCapabilityOptions = computed<
   Array<{ value: OpenAIEndpointCapability; label: string }>
 >(() => [
   { value: 'chat_completions', label: openAITextEndpointCapabilityLabel.value },
-  { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') }
+  { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') },
+  { value: 'seedance', label: 'Seedance (Ark)' }
 ])
 const openAITextGenerationCapabilityEnabled = computed(() =>
   openAIEndpointCapabilities.value.includes('chat_completions')
@@ -1796,9 +1797,9 @@ const openAIResponsesModeApplicable = computed(
 )
 
 const normalizeOpenAIEndpointCapabilities = (values: OpenAIEndpointCapability[]) => {
-  const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings']
+  const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings', 'seedance']
   const selected = allowed.filter((value) => values.includes(value))
-  return selected.length > 0 ? selected : allowed
+  return selected.length > 0 ? selected : ['chat_completions', 'embeddings'] as OpenAIEndpointCapability[]
 }
 
 const toggleOpenAIEndpointCapability = (
@@ -1996,7 +1997,7 @@ const buildUpdatePayload = (): Record<string, unknown> | null => {
 
   if (applyOpenAIEndpointCapabilities) {
     credentials.openai_capabilities =
-      openAIEndpointCapabilities.value.length === 2
+      openAIEndpointCapabilities.value.length === 2 && !openAIEndpointCapabilities.value.includes('seedance')
         ? null
         : [...openAIEndpointCapabilities.value]
     credentialsChanged = true

frontend/src/components/account/CreateAccountModal.vue

@@ -4524,16 +4524,17 @@ const openAITextEndpointCapabilityLabel = computed(() => {
 })
 const openAIEndpointCapabilityOptions = computed<{ value: OpenAIEndpointCapability; label: string }[]>(() => [
   { value: 'chat_completions', label: openAITextEndpointCapabilityLabel.value },
-  { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') }
+  { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') },
+  { value: 'seedance', label: 'Seedance (Ark)' }
 ])
 const openAITextGenerationCapabilityEnabled = computed(() =>
   openAIEndpointCapabilities.value.includes('chat_completions')
 )
 
 const normalizeOpenAIEndpointCapabilities = (values: OpenAIEndpointCapability[]) => {
-  const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings']
+  const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings', 'seedance']
   const selected = allowed.filter((value) => values.includes(value))
-  return selected.length > 0 ? selected : allowed
+  return selected.length > 0 ? selected : ['chat_completions', 'embeddings'] as OpenAIEndpointCapability[]
 }
 
 const toggleOpenAIEndpointCapability = (capability: OpenAIEndpointCapability, event?: Event) => {
@@ -4559,7 +4560,7 @@ const toggleOpenAIEndpointCapability = (capability: OpenAIEndpointCapability, ev
 
 const applyOpenAIEndpointCapabilities = (credentials: Record<string, unknown>) => {
   const capabilities = normalizeOpenAIEndpointCapabilities(openAIEndpointCapabilities.value)
-  if (capabilities.length === 2) {
+  if (capabilities.length === 2 && !capabilities.includes('seedance')) {
     delete credentials.openai_capabilities
     return
   }

frontend/src/components/account/EditAccountModal.vue

@@ -3683,16 +3683,17 @@ const openAITextEndpointCapabilityLabel = computed(() => {
 })
 const openAIEndpointCapabilityOptions = computed<{ value: OpenAIEndpointCapability; label: string }[]>(() => [
   { value: 'chat_completions', label: openAITextEndpointCapabilityLabel.value },
-  { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') }
+  { value: 'embeddings', label: t('admin.accounts.openai.capabilityEmbeddings') },
+  { value: 'seedance', label: 'Seedance (Ark)' }
 ])
 const openAITextGenerationCapabilityEnabled = computed(() =>
   openAIEndpointCapabilities.value.includes('chat_completions')
 )
 
 const normalizeOpenAIEndpointCapabilities = (values: OpenAIEndpointCapability[]) => {
-  const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings']
+  const allowed: OpenAIEndpointCapability[] = ['chat_completions', 'embeddings', 'seedance']
   const selected = allowed.filter((value) => values.includes(value))
-  return selected.length > 0 ? selected : allowed
+  return selected.length > 0 ? selected : ['chat_completions', 'embeddings'] as OpenAIEndpointCapability[]
 }
 
 const readOpenAIEndpointCapabilities = (credentials?: Record<string, unknown>): OpenAIEndpointCapability[] => {
@@ -3700,7 +3701,7 @@ const readOpenAIEndpointCapabilities = (credentials?: Record<string, unknown>):
   if (Array.isArray(raw)) {
     return normalizeOpenAIEndpointCapabilities(
       raw.filter((value): value is OpenAIEndpointCapability =>
-        value === 'chat_completions' || value === 'embeddings'
+        value === 'chat_completions' || value === 'embeddings' || value === 'seedance'
       )
     )
   }
@@ -3738,7 +3739,7 @@ const toggleOpenAIEndpointCapability = (capability: OpenAIEndpointCapability, ev
 
 const applyOpenAIEndpointCapabilities = (credentials: Record<string, unknown>) => {
   const capabilities = normalizeOpenAIEndpointCapabilities(openAIEndpointCapabilities.value)
-  if (capabilities.length === 2) {
+  if (capabilities.length === 2 && !capabilities.includes('seedance')) {
     delete credentials.openai_capabilities
     return
   }

frontend/src/components/account/__tests__/BulkEditAccountModal.spec.ts

@@ -557,6 +557,18 @@ describe('BulkEditAccountModal', () => {
     })
   })
 
+  it('persists Seedance in a two-capability bulk update', async () => {
+    const wrapper = mountModal({ selectedPlatforms: ['openai'], selectedTypes: ['apikey'] })
+    await wrapper.get('#bulk-edit-openai-endpoint-capabilities-enabled').setValue(true)
+    await wrapper.get('[data-testid="bulk-edit-openai-endpoint-capability-embeddings"]').setValue(false)
+    await wrapper.get('[data-testid="bulk-edit-openai-endpoint-capability-seedance"]').setValue(true)
+    await wrapper.get('#bulk-edit-account-form').trigger('submit.prevent')
+    await flushPromises()
+    expect(adminAPI.accounts.bulkUpdate).toHaveBeenCalledWith([1, 2], {
+      credentials: { openai_capabilities: ['chat_completions', 'seedance'] }
+    })
+  })
+
   it('关闭端点能力修改后 Responses 路由恢复独立可编辑', async () => {
     const wrapper = mountModal({
       selectedPlatforms: ['openai'],

frontend/src/components/account/__tests__/EditAccountModal.spec.ts

@@ -1311,6 +1311,19 @@ describe('EditAccountModal', () => {
 	  expect(updateAccountMock.mock.calls[0]?.[1]?.extra?.auto_pause_7d_disabled).toBeUndefined()
 	})
 
+  it('preserves Seedance when exactly two endpoint capabilities are selected', async () => {
+    const account = buildAccount()
+    account.credentials.openai_capabilities = ['chat_completions', 'seedance']
+    updateAccountMock.mockReset()
+    checkMixedChannelRiskMock.mockReset()
+    checkMixedChannelRiskMock.mockResolvedValue({ has_risk: false })
+    updateAccountMock.mockResolvedValue(account)
+    const wrapper = mountModal(account)
+    expect(wrapper.get<HTMLInputElement>('[data-testid="openai-endpoint-capability-seedance"]').element.checked).toBe(true)
+    await wrapper.get('form#edit-account-form').trigger('submit.prevent')
+    expect(updateAccountMock.mock.calls[0]?.[1]?.credentials?.openai_capabilities).toEqual(['chat_completions', 'seedance'])
+  })
+
   it('keeps at least one OpenAI APIKey endpoint capability selected', async () => {
     const account = buildAccount()
     updateAccountMock.mockReset()

frontend/src/types/index.ts

@@ -1455,7 +1455,7 @@ export interface CodexUsageSnapshot {
 
 export type OpenAICompactMode = 'auto' | 'force_on' | 'force_off'
 export type OpenAIResponsesMode = 'auto' | 'force_responses' | 'force_chat_completions'
-export type OpenAIEndpointCapability = 'chat_completions' | 'embeddings'
+export type OpenAIEndpointCapability = 'chat_completions' | 'embeddings' | 'seedance'
 
 export interface OpenAICompactState {
   openai_compact_mode?: OpenAICompactMode