feat(gateway): add web search emulation for Anthropic API Key accounts

Inject web search capability for Claude Console (API Key) accounts that don't natively support Anthropic's web_search tool. When a pure web_search request is detected, the gateway calls Brave Search or Tavily API directly and constructs an Anthropic-protocol-compliant SSE/JSON response without forwarding to upstream. Backend: - New `pkg/websearch/` SDK: Brave and Tavily provider implementations with io.LimitReader, proxy support, and Redis-based quota tracking (Lua atomic INCR + TTL, DECR rollback on failure) - Global config via `settings.web_search_emulation_config` (JSON) with in-process cache + singleflight, input validation, API key merge on save, and sanitized API responses - Channel-level toggle via `channels.features_config` JSONB column (DB migration 101) - Account-level toggle via `accounts.extra.web_search_emulation` - Request interception in `Forward()` with SSE streaming response construction using json.Marshal (no manual string concatenation) - Manager hot-reload: `RebuildWebSearchManager()` called on config save and startup via `SetWebSearchRedisClient()` - 70 unit tests covering providers, manager, config validation, sanitization, tool detection, query extraction, and response building Frontend: - Settings → Gateway tab: Web Search Emulation config card with global toggle, provider list (add/remove, API key, priority, quota, proxy) - Channels → Anthropic tab: web search emulation toggle with global state linkage (disabled when global off) - Account Create/Edit modals: web search emulation toggle for API Key type with Toggle component - Full i18n coverage (zh + en)
2026-04-12 00:02:26 +08:00
parent c738cfec93
commit 1b53ffcac7
37 changed files with 3507 additions and 238 deletions
--- a/backend/internal/handler/admin/channel_handler.go
+++ b/backend/internal/handler/admin/channel_handler.go
@@ -34,6 +34,7 @@ type createChannelRequest struct {
 	BillingModelSource string                       `json:"billing_model_source" binding:"omitempty,oneof=requested upstream channel_mapped"`
 	RestrictModels     bool                         `json:"restrict_models"`
 	Features           string                       `json:"features"`
+	FeaturesConfig     map[string]any               `json:"features_config"`
 }

 type updateChannelRequest struct {
@@ -46,6 +47,7 @@ type updateChannelRequest struct {
 	BillingModelSource string                        `json:"billing_model_source" binding:"omitempty,oneof=requested upstream channel_mapped"`
 	RestrictModels     *bool                         `json:"restrict_models"`
 	Features           *string                       `json:"features"`
+	FeaturesConfig     map[string]any                `json:"features_config"`
 }

 type channelModelPricingRequest struct {
@@ -81,6 +83,7 @@ type channelResponse struct {
 	BillingModelSource string                        `json:"billing_model_source"`
 	RestrictModels     bool                          `json:"restrict_models"`
 	Features           string                        `json:"features"`
+	FeaturesConfig     map[string]any                `json:"features_config"`
 	GroupIDs           []int64                       `json:"group_ids"`
 	ModelPricing       []channelModelPricingResponse `json:"model_pricing"`
 	ModelMapping       map[string]map[string]string  `json:"model_mapping"`
@@ -126,6 +129,7 @@ func channelToResponse(ch *service.Channel) *channelResponse {
 		Status:         ch.Status,
 		RestrictModels: ch.RestrictModels,
 		Features:       ch.Features,
+		FeaturesConfig: ch.FeaturesConfig,
 		GroupIDs:       ch.GroupIDs,
 		ModelMapping:   ch.ModelMapping,
 		CreatedAt:      ch.CreatedAt.Format("2006-01-02T15:04:05Z"),
@@ -305,6 +309,7 @@ func (h *ChannelHandler) Create(c *gin.Context) {
 		BillingModelSource: req.BillingModelSource,
 		RestrictModels:     req.RestrictModels,
 		Features:           req.Features,
+		FeaturesConfig:     req.FeaturesConfig,
 	})
 	if err != nil {
 		response.ErrorFrom(c, err)
@@ -338,6 +343,7 @@ func (h *ChannelHandler) Update(c *gin.Context) {
 		BillingModelSource: req.BillingModelSource,
 		RestrictModels:     req.RestrictModels,
 		Features:           req.Features,
+		FeaturesConfig:     req.FeaturesConfig,
 	}
 	if req.ModelPricing != nil {
 		pricing := pricingRequestToService(*req.ModelPricing)
--- a/backend/internal/handler/admin/setting_handler.go
+++ b/backend/internal/handler/admin/setting_handler.go
@@ -175,6 +175,7 @@ func (h *SettingHandler) GetSettings(c *gin.Context) {
 		EnableFingerprintUnification:         settings.EnableFingerprintUnification,
 		EnableMetadataPassthrough:            settings.EnableMetadataPassthrough,
 		EnableCCHSigning:                     settings.EnableCCHSigning,
+		WebSearchEmulationEnabled:            settings.WebSearchEmulationEnabled,
 		PaymentEnabled:                       paymentCfg.Enabled,
 		PaymentMinAmount:                     paymentCfg.MinAmount,
 		PaymentMaxAmount:                     paymentCfg.MaxAmount,
@@ -1847,3 +1848,37 @@ func (h *SettingHandler) UpdateStreamTimeoutSettings(c *gin.Context) {
 		ThresholdWindowMinutes: updatedSettings.ThresholdWindowMinutes,
 	})
 }
+
+// GetWebSearchEmulationConfig 获取 Web Search 模拟配置
+// GET /api/v1/admin/settings/web-search-emulation
+func (h *SettingHandler) GetWebSearchEmulationConfig(c *gin.Context) {
+	cfg, err := h.settingService.GetWebSearchEmulationConfig(c.Request.Context())
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	response.Success(c, service.SanitizeWebSearchConfig(cfg))
+}
+
+// UpdateWebSearchEmulationConfig 更新 Web Search 模拟配置
+// PUT /api/v1/admin/settings/web-search-emulation
+func (h *SettingHandler) UpdateWebSearchEmulationConfig(c *gin.Context) {
+	var cfg service.WebSearchEmulationConfig
+	if err := c.ShouldBindJSON(&cfg); err != nil {
+		response.BadRequest(c, "Invalid request: "+err.Error())
+		return
+	}
+
+	if err := h.settingService.SaveWebSearchEmulationConfig(c.Request.Context(), &cfg); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	// Re-read (with sanitized api keys) to return current state
+	updated, err := h.settingService.GetWebSearchEmulationConfig(c.Request.Context())
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+	response.Success(c, service.SanitizeWebSearchConfig(updated))
+}
--- a/backend/internal/handler/dto/settings.go
+++ b/backend/internal/handler/dto/settings.go
@@ -124,6 +124,9 @@ type SystemSettings struct {
 	EnableMetadataPassthrough    bool `json:"enable_metadata_passthrough"`
 	EnableCCHSigning             bool `json:"enable_cch_signing"`

+	// Web Search Emulation
+	WebSearchEmulationEnabled bool `json:"web_search_emulation_enabled"`
+
 	// Payment configuration
 	PaymentEnabled           bool     `json:"payment_enabled"`
 	PaymentMinAmount         float64  `json:"payment_min_amount"`
--- a/backend/internal/pkg/websearch/brave.go
+++ b/backend/internal/pkg/websearch/brave.go
@@ -0,0 +1,106 @@
+package websearch
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+)
+
+const (
+	braveSearchEndpoint = "https://api.search.brave.com/res/v1/web/search"
+	braveMaxCount       = 20
+	braveProviderName   = "brave"
+)
+
+// braveSearchURL is pre-parsed at init time; url.Parse cannot fail on a constant literal.
+var braveSearchURL, _ = url.Parse(braveSearchEndpoint) //nolint:errcheck
+
+// BraveProvider implements web search via the Brave Search API.
+type BraveProvider struct {
+	apiKey     string
+	httpClient *http.Client
+}
+
+// NewBraveProvider creates a Brave Search provider.
+// The caller is responsible for configuring the http.Client with proxy/timeouts.
+func NewBraveProvider(apiKey string, httpClient *http.Client) *BraveProvider {
+	if httpClient == nil {
+		httpClient = http.DefaultClient
+	}
+	return &BraveProvider{apiKey: apiKey, httpClient: httpClient}
+}
+
+func (b *BraveProvider) Name() string { return braveProviderName }
+
+func (b *BraveProvider) Search(ctx context.Context, req SearchRequest) (*SearchResponse, error) {
+	count := req.MaxResults
+	if count <= 0 {
+		count = defaultMaxResults
+	}
+	if count > braveMaxCount {
+		count = braveMaxCount
+	}
+
+	u := *braveSearchURL // copy the pre-parsed URL
+	q := u.Query()
+	q.Set("q", req.Query)
+	q.Set("count", strconv.Itoa(count))
+	u.RawQuery = q.Encode()
+
+	httpReq, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
+	if err != nil {
+		return nil, fmt.Errorf("brave: build request: %w", err)
+	}
+	httpReq.Header.Set("X-Subscription-Token", b.apiKey)
+	httpReq.Header.Set("Accept", "application/json")
+
+	resp, err := b.httpClient.Do(httpReq)
+	if err != nil {
+		return nil, fmt.Errorf("brave: request failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseSize))
+	if err != nil {
+		return nil, fmt.Errorf("brave: read body: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("brave: status %d: %s", resp.StatusCode, truncateBody(body))
+	}
+
+	var raw braveResponse
+	if err := json.Unmarshal(body, &raw); err != nil {
+		return nil, fmt.Errorf("brave: decode response: %w", err)
+	}
+
+	results := make([]SearchResult, 0, len(raw.Web.Results))
+	for _, r := range raw.Web.Results {
+		results = append(results, SearchResult{
+			URL:     r.URL,
+			Title:   r.Title,
+			Snippet: r.Description,
+			PageAge: r.Age,
+		})
+	}
+
+	return &SearchResponse{Results: results, Query: req.Query}, nil
+}
+
+// braveResponse is the minimal structure of the Brave Search API response.
+type braveResponse struct {
+	Web struct {
+		Results []braveResult `json:"results"`
+	} `json:"web"`
+}
+
+type braveResult struct {
+	URL         string `json:"url"`
+	Title       string `json:"title"`
+	Description string `json:"description"`
+	Age         string `json:"age"`
+}
--- a/backend/internal/pkg/websearch/brave_test.go
+++ b/backend/internal/pkg/websearch/brave_test.go
@@ -0,0 +1,119 @@
+package websearch
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestBraveProvider_Name(t *testing.T) {
+	p := NewBraveProvider("key", nil)
+	require.Equal(t, "brave", p.Name())
+}
+
+func TestBraveProvider_Search_Success(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		require.Equal(t, "test-key", r.Header.Get("X-Subscription-Token"))
+		require.Equal(t, "application/json", r.Header.Get("Accept"))
+		require.Equal(t, "golang", r.URL.Query().Get("q"))
+		require.Equal(t, "3", r.URL.Query().Get("count"))
+
+		resp := braveResponse{}
+		resp.Web.Results = []braveResult{
+			{URL: "https://go.dev", Title: "Go", Description: "Go lang", Age: "1 day"},
+			{URL: "https://pkg.go.dev", Title: "Pkg", Description: "Packages"},
+			{URL: "https://tour.go.dev", Title: "Tour", Description: "A Tour of Go", Age: "3 days"},
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer srv.Close()
+
+	p := NewBraveProvider("test-key", srv.Client())
+	// Override the endpoint for testing
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srv.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	resp, err := p.Search(context.Background(), SearchRequest{Query: "golang", MaxResults: 3})
+	require.NoError(t, err)
+	require.Len(t, resp.Results, 3)
+	require.Equal(t, "https://go.dev", resp.Results[0].URL)
+	require.Equal(t, "Go lang", resp.Results[0].Snippet)
+	require.Equal(t, "1 day", resp.Results[0].PageAge)
+}
+
+func TestBraveProvider_Search_DefaultMaxResults(t *testing.T) {
+	var receivedCount string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		receivedCount = r.URL.Query().Get("count")
+		resp := braveResponse{}
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer srv.Close()
+
+	p := NewBraveProvider("key", srv.Client())
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srv.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	_, _ = p.Search(context.Background(), SearchRequest{Query: "test", MaxResults: 0})
+	require.Equal(t, "5", receivedCount)
+}
+
+func TestBraveProvider_Search_HTTPError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(429)
+		w.Write([]byte("rate limited"))
+	}))
+	defer srv.Close()
+
+	p := NewBraveProvider("key", srv.Client())
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srv.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	_, err := p.Search(context.Background(), SearchRequest{Query: "test"})
+	require.ErrorContains(t, err, "brave: status 429")
+}
+
+func TestBraveProvider_Search_InvalidJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Write([]byte("not json"))
+	}))
+	defer srv.Close()
+
+	p := NewBraveProvider("key", srv.Client())
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srv.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	_, err := p.Search(context.Background(), SearchRequest{Query: "test"})
+	require.ErrorContains(t, err, "brave: decode response")
+}
+
+func TestBraveProvider_Search_EmptyResults(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		resp := braveResponse{}
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer srv.Close()
+
+	p := NewBraveProvider("key", srv.Client())
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srv.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	resp, err := p.Search(context.Background(), SearchRequest{Query: "test"})
+	require.NoError(t, err)
+	require.Empty(t, resp.Results)
+}
--- a/backend/internal/pkg/websearch/helpers.go
+++ b/backend/internal/pkg/websearch/helpers.go
@@ -0,0 +1,14 @@
+package websearch
+
+const (
+	maxResponseSize   = 1 << 20 // 1 MB
+	errorBodyTruncLen = 200
+)
+
+// truncateBody returns a truncated string of body for error messages.
+func truncateBody(body []byte) string {
+	if len(body) <= errorBodyTruncLen {
+		return string(body)
+	}
+	return string(body[:errorBodyTruncLen]) + "...(truncated)"
+}
--- a/backend/internal/pkg/websearch/helpers_test.go
+++ b/backend/internal/pkg/websearch/helpers_test.go
@@ -0,0 +1,25 @@
+package websearch
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestTruncateBody_Short(t *testing.T) {
+	body := []byte("short body")
+	require.Equal(t, "short body", truncateBody(body))
+}
+
+func TestTruncateBody_Long(t *testing.T) {
+	body := []byte(strings.Repeat("x", 500))
+	result := truncateBody(body)
+	require.Len(t, result, errorBodyTruncLen+len("...(truncated)"))
+	require.True(t, strings.HasSuffix(result, "...(truncated)"))
+}
+
+func TestTruncateBody_ExactBoundary(t *testing.T) {
+	body := []byte(strings.Repeat("x", errorBodyTruncLen))
+	require.Equal(t, string(body), truncateBody(body))
+}
--- a/backend/internal/pkg/websearch/manager.go
+++ b/backend/internal/pkg/websearch/manager.go
@@ -0,0 +1,273 @@
+package websearch
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// Quota refresh interval constants.
+const (
+	QuotaRefreshDaily   = "daily"
+	QuotaRefreshWeekly  = "weekly"
+	QuotaRefreshMonthly = "monthly"
+)
+
+// ProviderConfig holds the configuration for a single search provider.
+type ProviderConfig struct {
+	Type                 string `json:"type"`                   // ProviderTypeBrave | ProviderTypeTavily
+	APIKey               string `json:"api_key"`                // secret
+	Priority             int    `json:"priority"`               // lower = higher priority
+	QuotaLimit           int64  `json:"quota_limit"`            // 0 = unlimited
+	QuotaRefreshInterval string `json:"quota_refresh_interval"` // QuotaRefreshDaily / Weekly / Monthly
+	ProxyURL             string `json:"-"`                      // resolved proxy URL (not persisted)
+	ExpiresAt            *int64 `json:"expires_at,omitempty"`   // optional expiration (unix seconds)
+}
+
+// Manager selects providers by priority and tracks quota via Redis.
+type Manager struct {
+	configs []ProviderConfig
+	redis   *redis.Client
+
+	clientMu    sync.Mutex
+	clientCache map[string]*http.Client
+}
+
+const (
+	quotaKeyPrefix       = "websearch:quota:"
+	searchRequestTimeout = 30 * time.Second
+	quotaTTLBuffer       = 24 * time.Hour
+	maxCachedClients     = 100
+)
+
+// quotaIncrScript atomically increments the counter and sets TTL on first creation.
+// KEYS[1] = quota key, ARGV[1] = TTL in seconds.
+// Returns the new counter value.
+var quotaIncrScript = redis.NewScript(`
+local val = redis.call('INCR', KEYS[1])
+if val == 1 then
+  redis.call('EXPIRE', KEYS[1], ARGV[1])
+else
+  -- Defensive: ensure TTL exists even if a prior EXPIRE failed
+  local ttl = redis.call('TTL', KEYS[1])
+  if ttl == -1 then
+    redis.call('EXPIRE', KEYS[1], ARGV[1])
+  end
+end
+return val
+`)
+
+// NewManager creates a Manager with the given provider configs and Redis client.
+func NewManager(configs []ProviderConfig, redisClient *redis.Client) *Manager {
+	sorted := make([]ProviderConfig, len(configs))
+	copy(sorted, configs)
+	sort.Slice(sorted, func(i, j int) bool {
+		return sorted[i].Priority < sorted[j].Priority
+	})
+	return &Manager{
+		configs:     sorted,
+		redis:       redisClient,
+		clientCache: make(map[string]*http.Client),
+	}
+}
+
+// SearchWithBestProvider selects the highest-priority available provider,
+// reserves quota, executes the search, and rolls back quota on failure.
+func (m *Manager) SearchWithBestProvider(ctx context.Context, req SearchRequest) (*SearchResponse, string, error) {
+	if strings.TrimSpace(req.Query) == "" {
+		return nil, "", fmt.Errorf("websearch: empty search query")
+	}
+	for _, cfg := range m.configs {
+		if !m.isProviderAvailable(cfg) {
+			continue
+		}
+		allowed, incremented := m.tryReserveQuota(ctx, cfg)
+		if !allowed {
+			continue
+		}
+		resp, err := m.executeSearch(ctx, cfg, req)
+		if err != nil {
+			if incremented {
+				m.rollbackQuota(ctx, cfg)
+			}
+			slog.Warn("websearch: provider search failed",
+				"provider", cfg.Type, "error", err)
+			continue
+		}
+		return resp, cfg.Type, nil
+	}
+	return nil, "", fmt.Errorf("websearch: no available provider (all exhausted or failed)")
+}
+
+func (m *Manager) isProviderAvailable(cfg ProviderConfig) bool {
+	if cfg.APIKey == "" {
+		return false
+	}
+	if cfg.ExpiresAt != nil && time.Now().Unix() > *cfg.ExpiresAt {
+		slog.Info("websearch: provider expired, skipping",
+			"provider", cfg.Type, "expires_at", *cfg.ExpiresAt)
+		return false
+	}
+	return true
+}
+
+// tryReserveQuota atomically increments the counter via Lua script and checks limit.
+// Returns (allowed, incremented): allowed=true means the request may proceed;
+// incremented=true means the Redis counter was actually incremented (so rollback is needed on failure).
+func (m *Manager) tryReserveQuota(ctx context.Context, cfg ProviderConfig) (bool, bool) {
+	if cfg.QuotaLimit <= 0 {
+		return true, false // unlimited, no INCR
+	}
+	if m.redis == nil {
+		slog.Warn("websearch: Redis unavailable, quota check skipped",
+			"provider", cfg.Type)
+		return true, false // allowed but not incremented
+	}
+	key := quotaRedisKey(cfg.Type, cfg.QuotaRefreshInterval)
+	ttlSec := int(quotaTTL(cfg.QuotaRefreshInterval).Seconds())
+
+	newVal, err := quotaIncrScript.Run(ctx, m.redis, []string{key}, ttlSec).Int64()
+	if err != nil {
+		slog.Warn("websearch: quota Lua INCR failed, allowing request",
+			"provider", cfg.Type, "error", err)
+		return true, false // allowed but not incremented
+	}
+	if newVal > cfg.QuotaLimit {
+		if decrErr := m.redis.Decr(ctx, key).Err(); decrErr != nil {
+			slog.Warn("websearch: quota over-limit DECR failed",
+				"provider", cfg.Type, "error", decrErr)
+		}
+		slog.Info("websearch: provider quota exhausted",
+			"provider", cfg.Type, "used", newVal, "limit", cfg.QuotaLimit)
+		return false, false // rejected, already rolled back
+	}
+	return true, true // allowed and incremented
+}
+
+// rollbackQuota decrements the counter after a search failure.
+func (m *Manager) rollbackQuota(ctx context.Context, cfg ProviderConfig) {
+	if cfg.QuotaLimit <= 0 || m.redis == nil {
+		return
+	}
+	key := quotaRedisKey(cfg.Type, cfg.QuotaRefreshInterval)
+	if err := m.redis.Decr(ctx, key).Err(); err != nil {
+		slog.Warn("websearch: quota rollback DECR failed",
+			"provider", cfg.Type, "error", err)
+	}
+}
+
+func (m *Manager) executeSearch(ctx context.Context, cfg ProviderConfig, req SearchRequest) (*SearchResponse, error) {
+	proxyURL := cfg.ProxyURL
+	if req.ProxyURL != "" {
+		proxyURL = req.ProxyURL
+	}
+	client := m.getOrCreateHTTPClient(proxyURL)
+	provider := m.buildProvider(cfg, client)
+	return provider.Search(ctx, req)
+}
+
+// GetUsage returns the current usage count for the given provider.
+func (m *Manager) GetUsage(ctx context.Context, providerType, refreshInterval string) (int64, error) {
+	if m.redis == nil {
+		return 0, nil
+	}
+	key := quotaRedisKey(providerType, refreshInterval)
+	val, err := m.redis.Get(ctx, key).Int64()
+	if err == redis.Nil {
+		return 0, nil
+	}
+	return val, err
+}
+
+// GetAllUsage returns usage for every configured provider.
+func (m *Manager) GetAllUsage(ctx context.Context) map[string]int64 {
+	result := make(map[string]int64, len(m.configs))
+	for _, cfg := range m.configs {
+		used, _ := m.GetUsage(ctx, cfg.Type, cfg.QuotaRefreshInterval)
+		result[cfg.Type] = used
+	}
+	return result
+}
+
+// --- HTTP client cache (bounded) ---
+
+func (m *Manager) getOrCreateHTTPClient(proxyURL string) *http.Client {
+	m.clientMu.Lock()
+	defer m.clientMu.Unlock()
+
+	if c, ok := m.clientCache[proxyURL]; ok {
+		return c
+	}
+	if len(m.clientCache) >= maxCachedClients {
+		m.clientCache = make(map[string]*http.Client) // evict all
+	}
+	c := newHTTPClient(proxyURL)
+	m.clientCache[proxyURL] = c
+	return c
+}
+
+func newHTTPClient(proxyURL string) *http.Client {
+	transport := &http.Transport{
+		TLSClientConfig: &tls.Config{MinVersion: tls.VersionTLS12},
+	}
+	if proxyURL != "" {
+		if u, err := url.Parse(proxyURL); err == nil {
+			transport.Proxy = http.ProxyURL(u)
+		}
+	}
+	return &http.Client{Transport: transport, Timeout: searchRequestTimeout}
+}
+
+// --- Provider factory ---
+
+func (m *Manager) buildProvider(cfg ProviderConfig, client *http.Client) Provider {
+	switch cfg.Type {
+	case braveProviderName:
+		return NewBraveProvider(cfg.APIKey, client)
+	case tavilyProviderName:
+		return NewTavilyProvider(cfg.APIKey, client)
+	default:
+		slog.Warn("websearch: unknown provider type, falling back to brave",
+			"type", cfg.Type)
+		return NewBraveProvider(cfg.APIKey, client)
+	}
+}
+
+// --- Redis key helpers ---
+
+func quotaRedisKey(providerType, refreshInterval string) string {
+	return quotaKeyPrefix + providerType + ":" + periodKey(refreshInterval)
+}
+
+func periodKey(refreshInterval string) string {
+	now := time.Now().UTC()
+	switch refreshInterval {
+	case QuotaRefreshDaily:
+		return now.Format("2006-01-02")
+	case QuotaRefreshWeekly:
+		year, week := now.ISOWeek()
+		return fmt.Sprintf("%d-W%02d", year, week)
+	default: // QuotaRefreshMonthly
+		return now.Format("2006-01")
+	}
+}
+
+func quotaTTL(refreshInterval string) time.Duration {
+	switch refreshInterval {
+	case QuotaRefreshDaily:
+		return 24*time.Hour + quotaTTLBuffer
+	case QuotaRefreshWeekly:
+		return 7*24*time.Hour + quotaTTLBuffer
+	default:
+		return 31*24*time.Hour + quotaTTLBuffer
+	}
+}
--- a/backend/internal/pkg/websearch/manager_test.go
+++ b/backend/internal/pkg/websearch/manager_test.go
@@ -0,0 +1,149 @@
+package websearch
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewManager_SortsByPriority(t *testing.T) {
+	configs := []ProviderConfig{
+		{Type: "brave", APIKey: "k3", Priority: 30},
+		{Type: "tavily", APIKey: "k1", Priority: 10},
+	}
+	m := NewManager(configs, nil)
+	require.Equal(t, 10, m.configs[0].Priority)
+	require.Equal(t, 30, m.configs[1].Priority)
+}
+
+func TestManager_SearchWithBestProvider_EmptyQuery(t *testing.T) {
+	m := NewManager([]ProviderConfig{{Type: "brave", APIKey: "k"}}, nil)
+	_, _, err := m.SearchWithBestProvider(context.Background(), SearchRequest{Query: ""})
+	require.ErrorContains(t, err, "empty search query")
+
+	_, _, err = m.SearchWithBestProvider(context.Background(), SearchRequest{Query: "   "})
+	require.ErrorContains(t, err, "empty search query")
+}
+
+func TestManager_SearchWithBestProvider_SkipEmptyAPIKey(t *testing.T) {
+	m := NewManager([]ProviderConfig{{Type: "brave", APIKey: ""}}, nil)
+	_, _, err := m.SearchWithBestProvider(context.Background(), SearchRequest{Query: "test"})
+	require.ErrorContains(t, err, "no available provider")
+}
+
+func TestManager_SearchWithBestProvider_SkipExpired(t *testing.T) {
+	past := time.Now().Add(-1 * time.Hour).Unix()
+	m := NewManager([]ProviderConfig{
+		{Type: "brave", APIKey: "k", ExpiresAt: &past},
+	}, nil)
+	_, _, err := m.SearchWithBestProvider(context.Background(), SearchRequest{Query: "test"})
+	require.ErrorContains(t, err, "no available provider")
+}
+
+func TestManager_SearchWithBestProvider_PriorityOrder(t *testing.T) {
+	// Create two mock servers that return different results
+	srvBrave := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		resp := braveResponse{}
+		resp.Web.Results = []braveResult{{URL: "https://brave.com", Title: "Brave", Description: "from brave"}}
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer srvBrave.Close()
+
+	// Override brave endpoint for test
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srvBrave.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	m := NewManager([]ProviderConfig{
+		{Type: "brave", APIKey: "k1", Priority: 1},
+		{Type: "tavily", APIKey: "k2", Priority: 2},
+	}, nil)
+	// Inject the test server's client
+	m.clientCache[srvBrave.URL] = srvBrave.Client()
+	m.clientCache[""] = srvBrave.Client()
+
+	resp, providerName, err := m.SearchWithBestProvider(context.Background(), SearchRequest{Query: "test"})
+	require.NoError(t, err)
+	require.Equal(t, "brave", providerName)
+	require.Len(t, resp.Results, 1)
+	require.Equal(t, "from brave", resp.Results[0].Snippet)
+}
+
+func TestManager_SearchWithBestProvider_NilRedis(t *testing.T) {
+	// With nil Redis, quota check is skipped (always allowed)
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		resp := braveResponse{}
+		resp.Web.Results = []braveResult{{URL: "https://test.com", Title: "Test", Description: "result"}}
+		json.NewEncoder(w).Encode(resp)
+	}))
+	defer srv.Close()
+
+	origURL := *braveSearchURL
+	u, _ := http.NewRequest("GET", srv.URL, nil)
+	*braveSearchURL = *u.URL
+	defer func() { *braveSearchURL = origURL }()
+
+	m := NewManager([]ProviderConfig{
+		{Type: "brave", APIKey: "k", Priority: 1, QuotaLimit: 100},
+	}, nil) // nil Redis
+	m.clientCache[""] = srv.Client()
+
+	resp, _, err := m.SearchWithBestProvider(context.Background(), SearchRequest{Query: "test"})
+	require.NoError(t, err)
+	require.Len(t, resp.Results, 1)
+}
+
+func TestManager_GetUsage_NilRedis(t *testing.T) {
+	m := NewManager(nil, nil)
+	used, err := m.GetUsage(context.Background(), "brave", "monthly")
+	require.NoError(t, err)
+	require.Equal(t, int64(0), used)
+}
+
+func TestManager_GetAllUsage_NilRedis(t *testing.T) {
+	m := NewManager([]ProviderConfig{
+		{Type: "brave", QuotaRefreshInterval: "monthly"},
+	}, nil)
+	usage := m.GetAllUsage(context.Background())
+	require.Equal(t, int64(0), usage["brave"])
+}
+
+// --- Key/TTL helpers ---
+
+func TestQuotaTTL_Daily(t *testing.T) {
+	require.Equal(t, 24*time.Hour+quotaTTLBuffer, quotaTTL(QuotaRefreshDaily))
+}
+
+func TestQuotaTTL_Weekly(t *testing.T) {
+	require.Equal(t, 7*24*time.Hour+quotaTTLBuffer, quotaTTL(QuotaRefreshWeekly))
+}
+
+func TestQuotaTTL_Monthly(t *testing.T) {
+	require.Equal(t, 31*24*time.Hour+quotaTTLBuffer, quotaTTL(QuotaRefreshMonthly))
+}
+
+func TestPeriodKey_Daily(t *testing.T) {
+	key := periodKey(QuotaRefreshDaily)
+	require.Regexp(t, `^\d{4}-\d{2}-\d{2}$`, key)
+}
+
+func TestPeriodKey_Weekly(t *testing.T) {
+	key := periodKey(QuotaRefreshWeekly)
+	require.Regexp(t, `^\d{4}-W\d{2}$`, key)
+}
+
+func TestPeriodKey_Monthly(t *testing.T) {
+	key := periodKey(QuotaRefreshMonthly)
+	require.Regexp(t, `^\d{4}-\d{2}$`, key)
+}
+
+func TestQuotaRedisKey_Format(t *testing.T) {
+	key := quotaRedisKey("brave", QuotaRefreshDaily)
+	require.Contains(t, key, "websearch:quota:brave:")
+}
--- a/backend/internal/pkg/websearch/provider.go
+++ b/backend/internal/pkg/websearch/provider.go
@@ -0,0 +1,11 @@
+package websearch
+
+import "context"
+
+// Provider is the interface every search backend must implement.
+type Provider interface {
+	// Name returns the provider identifier ("brave" or "tavily").
+	Name() string
+	// Search executes a web search and returns results.
+	Search(ctx context.Context, req SearchRequest) (*SearchResponse, error)
+}
--- a/backend/internal/pkg/websearch/tavily.go
+++ b/backend/internal/pkg/websearch/tavily.go
@@ -0,0 +1,107 @@
+package websearch
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+const (
+	tavilySearchEndpoint   = "https://api.tavily.com/search"
+	tavilyProviderName     = "tavily"
+	tavilySearchDepthBasic = "basic"
+)
+
+// TavilyProvider implements web search via the Tavily Search API.
+type TavilyProvider struct {
+	apiKey     string
+	httpClient *http.Client
+}
+
+// NewTavilyProvider creates a Tavily Search provider.
+// The caller is responsible for configuring the http.Client with proxy/timeouts.
+func NewTavilyProvider(apiKey string, httpClient *http.Client) *TavilyProvider {
+	if httpClient == nil {
+		httpClient = http.DefaultClient
+	}
+	return &TavilyProvider{apiKey: apiKey, httpClient: httpClient}
+}
+
+func (t *TavilyProvider) Name() string { return tavilyProviderName }
+
+func (t *TavilyProvider) Search(ctx context.Context, req SearchRequest) (*SearchResponse, error) {
+	maxResults := req.MaxResults
+	if maxResults <= 0 {
+		maxResults = defaultMaxResults
+	}
+
+	payload := tavilyRequest{
+		APIKey:      t.apiKey,
+		Query:       req.Query,
+		MaxResults:  maxResults,
+		SearchDepth: tavilySearchDepthBasic,
+	}
+
+	bodyBytes, err := json.Marshal(payload)
+	if err != nil {
+		return nil, fmt.Errorf("tavily: encode request: %w", err)
+	}
+
+	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, tavilySearchEndpoint, bytes.NewReader(bodyBytes))
+	if err != nil {
+		return nil, fmt.Errorf("tavily: build request: %w", err)
+	}
+	httpReq.Header.Set("Content-Type", "application/json")
+
+	resp, err := t.httpClient.Do(httpReq)
+	if err != nil {
+		return nil, fmt.Errorf("tavily: request failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseSize))
+	if err != nil {
+		return nil, fmt.Errorf("tavily: read body: %w", err)
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("tavily: status %d: %s", resp.StatusCode, truncateBody(body))
+	}
+
+	var raw tavilyResponse
+	if err := json.Unmarshal(body, &raw); err != nil {
+		return nil, fmt.Errorf("tavily: decode response: %w", err)
+	}
+
+	results := make([]SearchResult, 0, len(raw.Results))
+	for _, r := range raw.Results {
+		results = append(results, SearchResult{
+			URL:     r.URL,
+			Title:   r.Title,
+			Snippet: r.Content,
+		})
+	}
+
+	return &SearchResponse{Results: results, Query: req.Query}, nil
+}
+
+type tavilyRequest struct {
+	APIKey      string `json:"api_key"`
+	Query       string `json:"query"`
+	MaxResults  int    `json:"max_results"`
+	SearchDepth string `json:"search_depth"`
+}
+
+type tavilyResponse struct {
+	Results []tavilyResult `json:"results"`
+}
+
+type tavilyResult struct {
+	URL     string  `json:"url"`
+	Title   string  `json:"title"`
+	Content string  `json:"content"`
+	Score   float64 `json:"score"`
+}
--- a/backend/internal/pkg/websearch/tavily_test.go
+++ b/backend/internal/pkg/websearch/tavily_test.go
@@ -0,0 +1,63 @@
+package websearch
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestTavilyProvider_Name(t *testing.T) {
+	p := NewTavilyProvider("key", nil)
+	require.Equal(t, "tavily", p.Name())
+}
+
+func TestTavilyProvider_Search_RequestConstruction(t *testing.T) {
+	// Verify tavilyRequest struct fields map correctly
+	req := tavilyRequest{
+		APIKey:      "test-key",
+		Query:       "golang",
+		MaxResults:  3,
+		SearchDepth: tavilySearchDepthBasic,
+	}
+	data, err := json.Marshal(req)
+	require.NoError(t, err)
+
+	var parsed map[string]any
+	require.NoError(t, json.Unmarshal(data, &parsed))
+	require.Equal(t, "test-key", parsed["api_key"])
+	require.Equal(t, "golang", parsed["query"])
+	require.Equal(t, float64(3), parsed["max_results"])
+	require.Equal(t, "basic", parsed["search_depth"])
+}
+
+func TestTavilyProvider_Search_ResponseParsing(t *testing.T) {
+	rawResp := `{"results":[{"url":"https://go.dev","title":"Go","content":"Go programming language","score":0.95}]}`
+	var resp tavilyResponse
+	require.NoError(t, json.Unmarshal([]byte(rawResp), &resp))
+	require.Len(t, resp.Results, 1)
+	require.Equal(t, "https://go.dev", resp.Results[0].URL)
+	require.Equal(t, "Go programming language", resp.Results[0].Content)
+	require.InDelta(t, 0.95, resp.Results[0].Score, 0.001)
+
+	// Verify mapping to SearchResult
+	results := make([]SearchResult, 0, len(resp.Results))
+	for _, r := range resp.Results {
+		results = append(results, SearchResult{
+			URL: r.URL, Title: r.Title, Snippet: r.Content,
+		})
+	}
+	require.Equal(t, "Go programming language", results[0].Snippet)
+	require.Equal(t, "", results[0].PageAge)
+}
+
+func TestTavilyProvider_Search_EmptyResults(t *testing.T) {
+	var resp tavilyResponse
+	require.NoError(t, json.Unmarshal([]byte(`{"results":[]}`), &resp))
+	require.Empty(t, resp.Results)
+}
+
+func TestTavilyProvider_Search_InvalidJSON(t *testing.T) {
+	var resp tavilyResponse
+	require.Error(t, json.Unmarshal([]byte("not json"), &resp))
+}
--- a/backend/internal/pkg/websearch/types.go
+++ b/backend/internal/pkg/websearch/types.go
@@ -0,0 +1,30 @@
+package websearch
+
+// SearchResult represents a single web search result.
+type SearchResult struct {
+	URL     string `json:"url"`
+	Title   string `json:"title"`
+	Snippet string `json:"snippet"`
+	PageAge string `json:"page_age,omitempty"`
+}
+
+// SearchRequest describes a web search to perform.
+type SearchRequest struct {
+	Query      string
+	MaxResults int    // defaults to defaultMaxResults if <= 0
+	ProxyURL   string // optional HTTP proxy URL
+}
+
+// SearchResponse holds the results of a web search.
+type SearchResponse struct {
+	Results []SearchResult
+	Query   string // the query that was actually executed
+}
+
+const defaultMaxResults = 5
+
+// Provider type identifiers.
+const (
+	ProviderTypeBrave  = "brave"
+	ProviderTypeTavily = "tavily"
+)
--- a/backend/internal/repository/channel_repo.go
+++ b/backend/internal/repository/channel_repo.go
@@ -41,10 +41,14 @@ func (r *channelRepository) Create(ctx context.Context, channel *service.Channel
 		if err != nil {
 			return err
 		}
+		featuresConfigJSON, err := marshalFeaturesConfig(channel.FeaturesConfig)
+		if err != nil {
+			return err
+		}
 		err = tx.QueryRowContext(ctx,
-			`INSERT INTO channels (name, description, status, model_mapping, billing_model_source, restrict_models, features) VALUES ($1, $2, $3, $4, $5, $6, $7)
+			`INSERT INTO channels (name, description, status, model_mapping, billing_model_source, restrict_models, features, features_config) VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
 			 RETURNING id, created_at, updated_at`,
-			channel.Name, channel.Description, channel.Status, modelMappingJSON, channel.BillingModelSource, channel.RestrictModels, channel.Features,
+			channel.Name, channel.Description, channel.Status, modelMappingJSON, channel.BillingModelSource, channel.RestrictModels, channel.Features, featuresConfigJSON,
 		).Scan(&channel.ID, &channel.CreatedAt, &channel.UpdatedAt)
 		if err != nil {
 			if isUniqueViolation(err) {
@@ -73,11 +77,11 @@ func (r *channelRepository) Create(ctx context.Context, channel *service.Channel

 func (r *channelRepository) GetByID(ctx context.Context, id int64) (*service.Channel, error) {
 	ch := &service.Channel{}
-	var modelMappingJSON []byte
+	var modelMappingJSON, featuresConfigJSON []byte
 	err := r.db.QueryRowContext(ctx,
-		`SELECT id, name, description, status, model_mapping, billing_model_source, restrict_models, features, created_at, updated_at
+		`SELECT id, name, description, status, model_mapping, billing_model_source, restrict_models, features, features_config, created_at, updated_at
 		 FROM channels WHERE id = $1`, id,
-	).Scan(&ch.ID, &ch.Name, &ch.Description, &ch.Status, &modelMappingJSON, &ch.BillingModelSource, &ch.RestrictModels, &ch.Features, &ch.CreatedAt, &ch.UpdatedAt)
+	).Scan(&ch.ID, &ch.Name, &ch.Description, &ch.Status, &modelMappingJSON, &ch.BillingModelSource, &ch.RestrictModels, &ch.Features, &featuresConfigJSON, &ch.CreatedAt, &ch.UpdatedAt)
 	if err == sql.ErrNoRows {
 		return nil, service.ErrChannelNotFound
 	}
@@ -85,6 +89,7 @@ func (r *channelRepository) GetByID(ctx context.Context, id int64) (*service.Cha
 		return nil, fmt.Errorf("get channel: %w", err)
 	}
 	ch.ModelMapping = unmarshalModelMapping(modelMappingJSON)
+	ch.FeaturesConfig = unmarshalFeaturesConfig(featuresConfigJSON)

 	groupIDs, err := r.GetGroupIDs(ctx, id)
 	if err != nil {
@@ -107,10 +112,14 @@ func (r *channelRepository) Update(ctx context.Context, channel *service.Channel
 		if err != nil {
 			return err
 		}
+		featuresConfigJSON, err := marshalFeaturesConfig(channel.FeaturesConfig)
+		if err != nil {
+			return err
+		}
 		result, err := tx.ExecContext(ctx,
-			`UPDATE channels SET name = $1, description = $2, status = $3, model_mapping = $4, billing_model_source = $5, restrict_models = $6, features = $7, updated_at = NOW()
-			 WHERE id = $8`,
-			channel.Name, channel.Description, channel.Status, modelMappingJSON, channel.BillingModelSource, channel.RestrictModels, channel.Features, channel.ID,
+			`UPDATE channels SET name = $1, description = $2, status = $3, model_mapping = $4, billing_model_source = $5, restrict_models = $6, features = $7, features_config = $8, updated_at = NOW()
+			 WHERE id = $9`,
+			channel.Name, channel.Description, channel.Status, modelMappingJSON, channel.BillingModelSource, channel.RestrictModels, channel.Features, featuresConfigJSON, channel.ID,
 		)
 		if err != nil {
 			if isUniqueViolation(err) {
@@ -187,9 +196,9 @@ func (r *channelRepository) List(ctx context.Context, params pagination.Paginati

 	// 查询 channel 列表
 	dataQuery := fmt.Sprintf(
-		`SELECT c.id, c.name, c.description, c.status, c.model_mapping, c.billing_model_source, c.restrict_models, c.features, c.created_at, c.updated_at
-		 FROM channels c WHERE %s ORDER BY c.id ASC LIMIT $%d OFFSET $%d`,
-		whereClause, argIdx, argIdx+1,
+		`SELECT c.id, c.name, c.description, c.status, c.model_mapping, c.billing_model_source, c.restrict_models, c.features, c.features_config, c.created_at, c.updated_at
+		 FROM channels c WHERE %s ORDER BY %s LIMIT $%d OFFSET $%d`,
+		whereClause, channelListOrderBy(params), argIdx, argIdx+1,
 	)
 	args = append(args, pageSize, offset)

@@ -203,11 +212,12 @@ func (r *channelRepository) List(ctx context.Context, params pagination.Paginati
 	var channelIDs []int64
 	for rows.Next() {
 		var ch service.Channel
-		var modelMappingJSON []byte
-		if err := rows.Scan(&ch.ID, &ch.Name, &ch.Description, &ch.Status, &modelMappingJSON, &ch.BillingModelSource, &ch.RestrictModels, &ch.Features, &ch.CreatedAt, &ch.UpdatedAt); err != nil {
+		var modelMappingJSON, featuresConfigJSON []byte
+		if err := rows.Scan(&ch.ID, &ch.Name, &ch.Description, &ch.Status, &modelMappingJSON, &ch.BillingModelSource, &ch.RestrictModels, &ch.Features, &featuresConfigJSON, &ch.CreatedAt, &ch.UpdatedAt); err != nil {
 			return nil, nil, fmt.Errorf("scan channel: %w", err)
 		}
 		ch.ModelMapping = unmarshalModelMapping(modelMappingJSON)
+		ch.FeaturesConfig = unmarshalFeaturesConfig(featuresConfigJSON)
 		channels = append(channels, ch)
 		channelIDs = append(channelIDs, ch.ID)
 	}
@@ -246,9 +256,34 @@ func (r *channelRepository) List(ctx context.Context, params pagination.Paginati
 	return channels, paginationResult, nil
 }

+func channelListOrderBy(params pagination.PaginationParams) string {
+	sortBy := strings.ToLower(strings.TrimSpace(params.SortBy))
+	sortOrder := strings.ToUpper(params.NormalizedSortOrder(pagination.SortOrderAsc))
+
+	var column string
+	switch sortBy {
+	case "":
+		column = "c.id"
+		sortOrder = "ASC"
+	case "id":
+		column = "c.id"
+	case "name":
+		column = "c.name"
+	case "status":
+		column = "c.status"
+	case "created_at":
+		column = "c.created_at"
+	default:
+		column = "c.id"
+		sortOrder = "ASC"
+	}
+
+	return fmt.Sprintf("%s %s, c.id %s", column, sortOrder, sortOrder)
+}
+
 func (r *channelRepository) ListAll(ctx context.Context) ([]service.Channel, error) {
 	rows, err := r.db.QueryContext(ctx,
-		`SELECT id, name, description, status, model_mapping, billing_model_source, restrict_models, features, created_at, updated_at FROM channels ORDER BY id`,
+		`SELECT id, name, description, status, model_mapping, billing_model_source, restrict_models, features, features_config, created_at, updated_at FROM channels ORDER BY id`,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("query all channels: %w", err)
@@ -259,11 +294,12 @@ func (r *channelRepository) ListAll(ctx context.Context) ([]service.Channel, err
 	var channelIDs []int64
 	for rows.Next() {
 		var ch service.Channel
-		var modelMappingJSON []byte
-		if err := rows.Scan(&ch.ID, &ch.Name, &ch.Description, &ch.Status, &modelMappingJSON, &ch.BillingModelSource, &ch.RestrictModels, &ch.Features, &ch.CreatedAt, &ch.UpdatedAt); err != nil {
+		var modelMappingJSON, featuresConfigJSON []byte
+		if err := rows.Scan(&ch.ID, &ch.Name, &ch.Description, &ch.Status, &modelMappingJSON, &ch.BillingModelSource, &ch.RestrictModels, &ch.Features, &featuresConfigJSON, &ch.CreatedAt, &ch.UpdatedAt); err != nil {
 			return nil, fmt.Errorf("scan channel: %w", err)
 		}
 		ch.ModelMapping = unmarshalModelMapping(modelMappingJSON)
+		ch.FeaturesConfig = unmarshalFeaturesConfig(featuresConfigJSON)
 		channels = append(channels, ch)
 		channelIDs = append(channelIDs, ch.ID)
 	}
@@ -431,6 +467,28 @@ func unmarshalModelMapping(data []byte) map[string]map[string]string {
 	return m
 }

+func marshalFeaturesConfig(m map[string]any) ([]byte, error) {
+	if len(m) == 0 {
+		return []byte("{}"), nil
+	}
+	data, err := json.Marshal(m)
+	if err != nil {
+		return nil, fmt.Errorf("marshal features_config: %w", err)
+	}
+	return data, nil
+}
+
+func unmarshalFeaturesConfig(data []byte) map[string]any {
+	if len(data) == 0 {
+		return nil
+	}
+	var m map[string]any
+	if err := json.Unmarshal(data, &m); err != nil {
+		return nil
+	}
+	return m
+}
+
 // GetGroupPlatforms 批量查询分组 ID 对应的平台
 func (r *channelRepository) GetGroupPlatforms(ctx context.Context, groupIDs []int64) (map[int64]string, error) {
 	if len(groupIDs) == 0 {
--- a/backend/internal/server/routes/admin.go
+++ b/backend/internal/server/routes/admin.go
@@ -407,6 +407,9 @@ func registerSettingsRoutes(admin *gin.RouterGroup, h *handler.Handlers) {
 		// Beta 策略配置
 		adminSettings.GET("/beta-policy", h.Admin.Setting.GetBetaPolicySettings)
 		adminSettings.PUT("/beta-policy", h.Admin.Setting.UpdateBetaPolicySettings)
+		// Web Search 模拟配置
+		adminSettings.GET("/web-search-emulation", h.Admin.Setting.GetWebSearchEmulationConfig)
+		adminSettings.PUT("/web-search-emulation", h.Admin.Setting.UpdateWebSearchEmulationConfig)
 	}
 }

--- a/backend/internal/service/account.go
+++ b/backend/internal/service/account.go
@@ -969,7 +969,7 @@ func (a *Account) IsOveragesEnabled() bool {
 	return false
 }

-// IsOpenAIPassthroughEnabled 返回 OpenAI 账号是否启用“自动透传（仅替换认证）”。
+// IsOpenAIPassthroughEnabled 返回 OpenAI 账号是否启用"自动透传（仅替换认证）"。
 //
 // 新字段：accounts.extra.openai_passthrough。
 // 兼容字段：accounts.extra.openai_oauth_passthrough（历史 OAuth 开关）。
@@ -1133,7 +1133,7 @@ func (a *Account) ResolveOpenAIResponsesWebSocketV2Mode(defaultMode string) stri
 	return resolvedDefault
 }

-// IsOpenAIWSForceHTTPEnabled 返回账号级“强制 HTTP”开关。
+// IsOpenAIWSForceHTTPEnabled 返回账号级"强制 HTTP"开关。
 // 字段：accounts.extra.openai_ws_force_http。
 func (a *Account) IsOpenAIWSForceHTTPEnabled() bool {
 	if a == nil || !a.IsOpenAI() || a.Extra == nil {
@@ -1158,7 +1158,7 @@ func (a *Account) IsOpenAIOAuthPassthroughEnabled() bool {
 	return a != nil && a.IsOpenAIOAuth() && a.IsOpenAIPassthroughEnabled()
 }

-// IsAnthropicAPIKeyPassthroughEnabled 返回 Anthropic API Key 账号是否启用“自动透传（仅替换认证）”。
+// IsAnthropicAPIKeyPassthroughEnabled 返回 Anthropic API Key 账号是否启用"自动透传（仅替换认证）"。
 // 字段：accounts.extra.anthropic_passthrough。
 // 字段缺失或类型不正确时，按 false（关闭）处理。
 func (a *Account) IsAnthropicAPIKeyPassthroughEnabled() bool {
@@ -1169,7 +1169,18 @@ func (a *Account) IsAnthropicAPIKeyPassthroughEnabled() bool {
 	return ok && enabled
 }

-// IsCodexCLIOnlyEnabled 返回 OpenAI OAuth 账号是否启用“仅允许 Codex 官方客户端”。
+// IsWebSearchEmulationEnabled 返回 Anthropic API Key 账号是否启用 web search 模拟。
+// 字段：accounts.extra.web_search_emulation。
+// 字段缺失或类型不正确时，按 false（关闭）处理。
+func (a *Account) IsWebSearchEmulationEnabled() bool {
+	if a == nil || a.Platform != PlatformAnthropic || a.Type != AccountTypeAPIKey || a.Extra == nil {
+		return false
+	}
+	enabled, ok := a.Extra[featureKeyWebSearchEmulation].(bool)
+	return ok && enabled
+}
+
+// IsCodexCLIOnlyEnabled 返回 OpenAI OAuth 账号是否启用"仅允许 Codex 官方客户端"。
 // 字段：accounts.extra.codex_cli_only。
 // 字段缺失或类型不正确时，按 false（关闭）处理。
 func (a *Account) IsCodexCLIOnlyEnabled() bool {
--- a/backend/internal/service/account_websearch_test.go
+++ b/backend/internal/service/account_websearch_test.go
@@ -0,0 +1,71 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestAccount_IsWebSearchEmulationEnabled_Enabled(t *testing.T) {
+	a := &Account{
+		Platform: PlatformAnthropic,
+		Type:     AccountTypeAPIKey,
+		Extra:    map[string]any{featureKeyWebSearchEmulation: true},
+	}
+	require.True(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_Disabled(t *testing.T) {
+	a := &Account{
+		Platform: PlatformAnthropic,
+		Type:     AccountTypeAPIKey,
+		Extra:    map[string]any{featureKeyWebSearchEmulation: false},
+	}
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_MissingField(t *testing.T) {
+	a := &Account{
+		Platform: PlatformAnthropic,
+		Type:     AccountTypeAPIKey,
+		Extra:    map[string]any{},
+	}
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_WrongType(t *testing.T) {
+	a := &Account{
+		Platform: PlatformAnthropic,
+		Type:     AccountTypeAPIKey,
+		Extra:    map[string]any{featureKeyWebSearchEmulation: "true"},
+	}
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_NilExtra(t *testing.T) {
+	a := &Account{Platform: PlatformAnthropic, Type: AccountTypeAPIKey, Extra: nil}
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_NilAccount(t *testing.T) {
+	var a *Account
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_NonAnthropicPlatform(t *testing.T) {
+	a := &Account{
+		Platform: PlatformOpenAI,
+		Type:     AccountTypeAPIKey,
+		Extra:    map[string]any{featureKeyWebSearchEmulation: true},
+	}
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
+
+func TestAccount_IsWebSearchEmulationEnabled_NonAPIKeyType(t *testing.T) {
+	a := &Account{
+		Platform: PlatformAnthropic,
+		Type:     AccountTypeOAuth,
+		Extra:    map[string]any{featureKeyWebSearchEmulation: true},
+	}
+	require.False(t, a.IsWebSearchEmulationEnabled())
+}
--- a/backend/internal/service/channel.go
+++ b/backend/internal/service/channel.go
@@ -49,6 +49,21 @@ type Channel struct {
 	ModelPricing []ChannelModelPricing
 	// 渠道级模型映射（按平台分组：platform → {src→dst}）
 	ModelMapping map[string]map[string]string
+	// 渠道特性配置（如 {"web_search_emulation": {"anthropic": true}}）
+	FeaturesConfig map[string]any
+}
+
+// IsWebSearchEmulationEnabled 返回该渠道是否为指定平台启用了 web search 模拟。
+func (c *Channel) IsWebSearchEmulationEnabled(platform string) bool {
+	if c == nil || c.FeaturesConfig == nil {
+		return false
+	}
+	wse, ok := c.FeaturesConfig[featureKeyWebSearchEmulation].(map[string]any)
+	if !ok {
+		return false
+	}
+	enabled, ok := wse[platform].(bool)
+	return ok && enabled
 }

 // ChannelModelPricing 渠道模型定价条目
--- a/backend/internal/service/channel_service.go
+++ b/backend/internal/service/channel_service.go
@@ -197,10 +197,8 @@ func newEmptyChannelCache() *channelCache {
 }

 // expandPricingToCache 将渠道的模型定价展开到缓存（按分组+平台维度）。
-// antigravity 平台同时服务 Claude 和 Gemini 模型，需匹配 anthropic/gemini 的定价条目。
-// 缓存 key 使用定价条目的原始平台（pricing.Platform），而非分组平台，
-// 避免跨平台同名模型（如 anthropic 和 gemini 都有 "model-x"）互相覆盖。
-// 查找时通过 lookupPricingAcrossPlatforms() 依次尝试所有匹配平台。
+// 各平台严格独立：antigravity 分组只匹配 antigravity 定价，不会匹配 anthropic/gemini 的定价。
+// 查找时通过 lookupPricingAcrossPlatforms() 在本平台内查找。
 func expandPricingToCache(cache *channelCache, ch *Channel, gid int64, platform string) {
 	for j := range ch.ModelPricing {
 		pricing := &ch.ModelPricing[j]
@@ -226,8 +224,7 @@ func expandPricingToCache(cache *channelCache, ch *Channel, gid int64, platform
 }

 // expandMappingToCache 将渠道的模型映射展开到缓存（按分组+平台维度）。
-// antigravity 平台同时服务 Claude 和 Gemini 模型。
-// 缓存 key 使用映射条目的原始平台（mappingPlatform），避免跨平台同名映射覆盖。
+// 各平台严格独立：antigravity 分组只匹配 antigravity 映射。
 func expandMappingToCache(cache *channelCache, ch *Channel, gid int64, platform string) {
 	for _, mappingPlatform := range matchingPlatforms(platform) {
 		platformMapping, ok := ch.ModelMapping[mappingPlatform]
@@ -251,40 +248,58 @@ func expandMappingToCache(cache *channelCache, ch *Channel, gid int64, platform
 	}
 }

+// storeErrorCache 存入短 TTL 空缓存，防止 DB 错误后紧密重试。
+// 通过回退 loadedAt 使剩余 TTL = channelErrorTTL。
+func (s *ChannelService) storeErrorCache() {
+	errorCache := newEmptyChannelCache()
+	errorCache.loadedAt = time.Now().Add(-(channelCacheTTL - channelErrorTTL))
+	s.cache.Store(errorCache)
+}
+
 // buildCache 从数据库构建渠道缓存。
 // 使用独立 context 避免请求取消导致空值被长期缓存。
 func (s *ChannelService) buildCache(ctx context.Context) (*channelCache, error) {
-	// 断开请求取消链，避免客户端断连导致空值被长期缓存
 	dbCtx, cancel := context.WithTimeout(context.WithoutCancel(ctx), channelCacheDBTimeout)
 	defer cancel()

-	channels, err := s.repo.ListAll(dbCtx)
+	channels, groupPlatforms, err := s.fetchChannelData(dbCtx)
 	if err != nil {
-		// error-TTL：失败时存入短 TTL 空缓存，防止紧密重试
-		slog.Warn("failed to build channel cache", "error", err)
-		errorCache := newEmptyChannelCache()
-		errorCache.loadedAt = time.Now().Add(-(channelCacheTTL - channelErrorTTL)) // 使剩余 TTL = errorTTL
-		s.cache.Store(errorCache)
-		return nil, fmt.Errorf("list all channels: %w", err)
+		return nil, err
+	}
+
+	cache := populateChannelCache(channels, groupPlatforms)
+	s.cache.Store(cache)
+	return cache, nil
+}
+
+// fetchChannelData 从数据库加载渠道列表和分组平台映射。
+func (s *ChannelService) fetchChannelData(ctx context.Context) ([]Channel, map[int64]string, error) {
+	channels, err := s.repo.ListAll(ctx)
+	if err != nil {
+		slog.Warn("failed to build channel cache", "error", err)
+		s.storeErrorCache()
+		return nil, nil, fmt.Errorf("list all channels: %w", err)
 	}

-	// 收集所有 groupID，批量查询 platform
 	var allGroupIDs []int64
 	for i := range channels {
 		allGroupIDs = append(allGroupIDs, channels[i].GroupIDs...)
 	}
+
 	groupPlatforms := make(map[int64]string)
 	if len(allGroupIDs) > 0 {
-		groupPlatforms, err = s.repo.GetGroupPlatforms(dbCtx, allGroupIDs)
+		groupPlatforms, err = s.repo.GetGroupPlatforms(ctx, allGroupIDs)
 		if err != nil {
 			slog.Warn("failed to load group platforms for channel cache", "error", err)
-			errorCache := newEmptyChannelCache()
-			errorCache.loadedAt = time.Now().Add(-(channelCacheTTL - channelErrorTTL))
-			s.cache.Store(errorCache)
-			return nil, fmt.Errorf("get group platforms: %w", err)
+			s.storeErrorCache()
+			return nil, nil, fmt.Errorf("get group platforms: %w", err)
 		}
 	}
+	return channels, groupPlatforms, nil
+}

+// populateChannelCache 将渠道列表和分组平台映射填充到缓存快照中。
+func populateChannelCache(channels []Channel, groupPlatforms map[int64]string) *channelCache {
 	cache := newEmptyChannelCache()
 	cache.groupPlatform = groupPlatforms
 	cache.byID = make(map[int64]*Channel, len(channels))
@@ -293,7 +308,6 @@ func (s *ChannelService) buildCache(ctx context.Context) (*channelCache, error)
 	for i := range channels {
 		ch := &channels[i]
 		cache.byID[ch.ID] = ch
-
 		for _, gid := range ch.GroupIDs {
 			cache.channelByGroupID[gid] = ch
 			platform := groupPlatforms[gid]
@@ -302,32 +316,20 @@ func (s *ChannelService) buildCache(ctx context.Context) (*channelCache, error)
 		}
 	}

-	// 通配符条目保持配置顺序（最先匹配到优先）
-
-	s.cache.Store(cache)
-	return cache, nil
+	return cache
 }

 // invalidateCache 使缓存失效，让下次读取时自然重建

 // isPlatformPricingMatch 判断定价条目的平台是否匹配分组平台。
-// antigravity 平台同时服务 Claude（anthropic）和 Gemini（gemini）模型，
-// 因此 antigravity 分组应匹配 anthropic 和 gemini 的定价条目。
+// 各平台（antigravity / anthropic / gemini / openai）严格独立，不跨平台匹配。
 func isPlatformPricingMatch(groupPlatform, pricingPlatform string) bool {
-	if groupPlatform == pricingPlatform {
-		return true
-	}
-	if groupPlatform == PlatformAntigravity {
-		return pricingPlatform == PlatformAnthropic || pricingPlatform == PlatformGemini
-	}
-	return false
+	return groupPlatform == pricingPlatform
 }

-// matchingPlatforms 返回分组平台对应的所有可匹配平台列表。
+// matchingPlatforms 返回分组平台对应的可匹配平台列表。
+// 各平台严格独立，只返回自身。
 func matchingPlatforms(groupPlatform string) []string {
-	if groupPlatform == PlatformAntigravity {
-		return []string{PlatformAntigravity, PlatformAnthropic, PlatformGemini}
-	}
 	return []string{groupPlatform}
 }
 func (s *ChannelService) invalidateCache() {
@@ -364,10 +366,8 @@ func (c *channelCache) matchWildcardMapping(groupID int64, platform, modelLower
 	return ""
 }

-// lookupPricingAcrossPlatforms 在所有匹配平台中查找模型定价。
-// antigravity 分组的缓存 key 使用定价条目的原始平台，因此查找时需依次尝试
-// matchingPlatforms() 返回的所有平台（antigravity → anthropic → gemini），
-// 返回第一个命中的结果。非 antigravity 平台只尝试自身。
+// lookupPricingAcrossPlatforms 在分组平台内查找模型定价。
+// 各平台严格独立，只在本平台内查找（先精确匹配，再通配符）。
 func lookupPricingAcrossPlatforms(cache *channelCache, groupID int64, groupPlatform, modelLower string) *ChannelModelPricing {
 	for _, p := range matchingPlatforms(groupPlatform) {
 		key := channelModelKey{groupID: groupID, platform: p, model: modelLower}
@@ -384,7 +384,7 @@ func lookupPricingAcrossPlatforms(cache *channelCache, groupID int64, groupPlatf
 	return nil
 }

-// lookupMappingAcrossPlatforms 在所有匹配平台中查找模型映射。
+// lookupMappingAcrossPlatforms 在分组平台内查找模型映射。
 // 逻辑与 lookupPricingAcrossPlatforms 相同：先精确查找，再通配符。
 func lookupMappingAcrossPlatforms(cache *channelCache, groupID int64, groupPlatform, modelLower string) string {
 	for _, p := range matchingPlatforms(groupPlatform) {
@@ -442,8 +442,7 @@ func (s *ChannelService) lookupGroupChannel(ctx context.Context, groupID int64)
 }

 // GetChannelModelPricing 获取指定分组+模型的渠道定价（热路径 O(1)）。
-// antigravity 分组依次尝试所有匹配平台（antigravity → anthropic → gemini），
-// 确保跨平台同名模型各自独立匹配。
+// 各平台严格独立，只在本平台内查找定价。
 func (s *ChannelService) GetChannelModelPricing(ctx context.Context, groupID int64, model string) *ChannelModelPricing {
 	lk, err := s.lookupGroupChannel(ctx, groupID)
 	if err != nil {
@@ -481,7 +480,10 @@ func (s *ChannelService) ResolveChannelMapping(ctx context.Context, groupID int6
 // 返回 true 表示模型被限制（不在允许列表中）。
 // 如果渠道未启用模型限制或分组无渠道关联，返回 false。
 func (s *ChannelService) IsModelRestricted(ctx context.Context, groupID int64, model string) bool {
-	lk, _ := s.lookupGroupChannel(ctx, groupID)
+	lk, err := s.lookupGroupChannel(ctx, groupID)
+	if err != nil {
+		slog.Warn("failed to load channel cache for model restriction check", "group_id", groupID, "error", err)
+	}
 	if lk == nil {
 		return false
 	}
@@ -524,7 +526,7 @@ func resolveMapping(lk *channelLookup, groupID int64, model string) ChannelMappi
 }

 // checkRestricted 基于已查找的渠道信息检查模型是否被限制。
-// antigravity 分组依次尝试所有匹配平台的定价列表。
+// 只在本平台的定价列表中查找。
 func checkRestricted(lk *channelLookup, groupID int64, model string) bool {
 	if !lk.channel.RestrictModels {
 		return false
@@ -552,6 +554,91 @@ func ReplaceModelInBody(body []byte, newModel string) []byte {
 	return newBody
 }

+// validateChannelConfig 校验渠道的定价和映射配置（冲突检测 + 区间校验 + 计费模式校验）。
+// Create 和 Update 共用此函数，避免重复。
+func validateChannelConfig(pricing []ChannelModelPricing, mapping map[string]map[string]string) error {
+	if err := validateNoConflictingModels(pricing); err != nil {
+		return err
+	}
+	if err := validatePricingIntervals(pricing); err != nil {
+		return err
+	}
+	if err := validateNoConflictingMappings(mapping); err != nil {
+		return err
+	}
+	return validatePricingBillingMode(pricing)
+}
+
+// validatePricingBillingMode 校验计费模式配置：按次/图片模式必须配价格或区间，所有价格字段不能为负，区间至少有一个价格字段。
+func validatePricingBillingMode(pricing []ChannelModelPricing) error {
+	for _, p := range pricing {
+		if err := checkBillingModeRequirements(p); err != nil {
+			return err
+		}
+		if err := checkPricesNotNegative(p); err != nil {
+			return err
+		}
+		if err := checkIntervalsHavePrices(p); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func checkBillingModeRequirements(p ChannelModelPricing) error {
+	if p.BillingMode == BillingModePerRequest || p.BillingMode == BillingModeImage {
+		if p.PerRequestPrice == nil && len(p.Intervals) == 0 {
+			return infraerrors.BadRequest(
+				"BILLING_MODE_MISSING_PRICE",
+				"per-request price or intervals required for per_request/image billing mode",
+			)
+		}
+	}
+	return nil
+}
+
+func checkPricesNotNegative(p ChannelModelPricing) error {
+	checks := []struct {
+		field string
+		val   *float64
+	}{
+		{"input_price", p.InputPrice},
+		{"output_price", p.OutputPrice},
+		{"cache_write_price", p.CacheWritePrice},
+		{"cache_read_price", p.CacheReadPrice},
+		{"image_output_price", p.ImageOutputPrice},
+		{"per_request_price", p.PerRequestPrice},
+	}
+	for _, c := range checks {
+		if c.val != nil && *c.val < 0 {
+			return infraerrors.BadRequest("NEGATIVE_PRICE", fmt.Sprintf("%s must be >= 0", c.field))
+		}
+	}
+	return nil
+}
+
+func checkIntervalsHavePrices(p ChannelModelPricing) error {
+	for _, iv := range p.Intervals {
+		if iv.InputPrice == nil && iv.OutputPrice == nil &&
+			iv.CacheWritePrice == nil && iv.CacheReadPrice == nil &&
+			iv.PerRequestPrice == nil {
+			return infraerrors.BadRequest(
+				"INTERVAL_MISSING_PRICE",
+				fmt.Sprintf("interval [%d, %s] has no price fields set for model %v",
+					iv.MinTokens, formatMaxTokens(iv.MaxTokens), p.Models),
+			)
+		}
+	}
+	return nil
+}
+
+func formatMaxTokens(max *int) string {
+	if max == nil {
+		return "∞"
+	}
+	return fmt.Sprintf("%d", *max)
+}
+
 // --- CRUD ---

 // Create 创建渠道
@@ -564,15 +651,8 @@ func (s *ChannelService) Create(ctx context.Context, input *CreateChannelInput)
 		return nil, ErrChannelExists
 	}

-	// 检查分组冲突
-	if len(input.GroupIDs) > 0 {
-		conflicting, err := s.repo.GetGroupsInOtherChannels(ctx, 0, input.GroupIDs)
-		if err != nil {
-			return nil, fmt.Errorf("check group conflicts: %w", err)
-		}
-		if len(conflicting) > 0 {
-			return nil, ErrGroupAlreadyInChannel
-		}
+	if err := s.checkGroupConflicts(ctx, 0, input.GroupIDs); err != nil {
+		return nil, err
 	}

 	channel := &Channel{
@@ -585,18 +665,13 @@ func (s *ChannelService) Create(ctx context.Context, input *CreateChannelInput)
 		ModelPricing:       input.ModelPricing,
 		ModelMapping:       input.ModelMapping,
 		Features:           input.Features,
+		FeaturesConfig:     input.FeaturesConfig,
 	}
 	if channel.BillingModelSource == "" {
 		channel.BillingModelSource = BillingModelSourceChannelMapped
 	}

-	if err := validateNoConflictingModels(channel.ModelPricing); err != nil {
-		return nil, err
-	}
-	if err := validatePricingIntervals(channel.ModelPricing); err != nil {
-		return nil, err
-	}
-	if err := validateNoConflictingMappings(channel.ModelMapping); err != nil {
+	if err := validateChannelConfig(channel.ModelPricing, channel.ModelMapping); err != nil {
 		return nil, err
 	}

@@ -620,105 +695,118 @@ func (s *ChannelService) Update(ctx context.Context, id int64, input *UpdateChan
 		return nil, fmt.Errorf("get channel: %w", err)
 	}

-	if input.Name != "" && input.Name != channel.Name {
-		exists, err := s.repo.ExistsByNameExcluding(ctx, input.Name, id)
-		if err != nil {
-			return nil, fmt.Errorf("check channel exists: %w", err)
-		}
-		if exists {
-			return nil, ErrChannelExists
-		}
-		channel.Name = input.Name
-	}
-
-	if input.Description != nil {
-		channel.Description = *input.Description
-	}
-
-	if input.Status != "" {
-		channel.Status = input.Status
-	}
-
-	if input.RestrictModels != nil {
-		channel.RestrictModels = *input.RestrictModels
-	}
-	if input.Features != nil {
-		channel.Features = *input.Features
-	}
-
-	// 检查分组冲突
-	if input.GroupIDs != nil {
-		conflicting, err := s.repo.GetGroupsInOtherChannels(ctx, id, *input.GroupIDs)
-		if err != nil {
-			return nil, fmt.Errorf("check group conflicts: %w", err)
-		}
-		if len(conflicting) > 0 {
-			return nil, ErrGroupAlreadyInChannel
-		}
-		channel.GroupIDs = *input.GroupIDs
-	}
-
-	if input.ModelPricing != nil {
-		channel.ModelPricing = *input.ModelPricing
-	}
-
-	if input.ModelMapping != nil {
-		channel.ModelMapping = input.ModelMapping
-	}
-
-	if input.BillingModelSource != "" {
-		channel.BillingModelSource = input.BillingModelSource
-	}
-
-	if err := validateNoConflictingModels(channel.ModelPricing); err != nil {
-		return nil, err
-	}
-	if err := validatePricingIntervals(channel.ModelPricing); err != nil {
-		return nil, err
-	}
-	if err := validateNoConflictingMappings(channel.ModelMapping); err != nil {
+	if err := s.applyUpdateInput(ctx, channel, input); err != nil {
 		return nil, err
 	}

-	// 先获取旧分组，Update 后旧分组关联已删除，无法再查到
-	var oldGroupIDs []int64
-	if s.authCacheInvalidator != nil {
-		var err2 error
-		oldGroupIDs, err2 = s.repo.GetGroupIDs(ctx, id)
-		if err2 != nil {
-			slog.Warn("failed to get old group IDs for cache invalidation", "channel_id", id, "error", err2)
-		}
+	if err := validateChannelConfig(channel.ModelPricing, channel.ModelMapping); err != nil {
+		return nil, err
 	}

+	oldGroupIDs := s.getOldGroupIDs(ctx, id)
+
 	if err := s.repo.Update(ctx, channel); err != nil {
 		return nil, fmt.Errorf("update channel: %w", err)
 	}

 	s.invalidateCache()
-
-	// 失效新旧分组的 auth 缓存
-	if s.authCacheInvalidator != nil {
-		seen := make(map[int64]struct{}, len(oldGroupIDs)+len(channel.GroupIDs))
-		for _, gid := range oldGroupIDs {
-			if _, ok := seen[gid]; !ok {
-				seen[gid] = struct{}{}
-				s.authCacheInvalidator.InvalidateAuthCacheByGroupID(ctx, gid)
-			}
-		}
-		for _, gid := range channel.GroupIDs {
-			if _, ok := seen[gid]; !ok {
-				seen[gid] = struct{}{}
-				s.authCacheInvalidator.InvalidateAuthCacheByGroupID(ctx, gid)
-			}
-		}
-	}
+	s.invalidateAuthCacheForGroups(ctx, oldGroupIDs, channel.GroupIDs)

 	return s.repo.GetByID(ctx, id)
 }

+// applyUpdateInput 将更新请求的字段应用到渠道实体上。
+func (s *ChannelService) applyUpdateInput(ctx context.Context, channel *Channel, input *UpdateChannelInput) error {
+	if input.Name != "" && input.Name != channel.Name {
+		exists, err := s.repo.ExistsByNameExcluding(ctx, input.Name, channel.ID)
+		if err != nil {
+			return fmt.Errorf("check channel exists: %w", err)
+		}
+		if exists {
+			return ErrChannelExists
+		}
+		channel.Name = input.Name
+	}
+	if input.Description != nil {
+		channel.Description = *input.Description
+	}
+	if input.Status != "" {
+		channel.Status = input.Status
+	}
+	if input.RestrictModels != nil {
+		channel.RestrictModels = *input.RestrictModels
+	}
+	if input.Features != nil {
+		channel.Features = *input.Features
+	}
+	if input.GroupIDs != nil {
+		if err := s.checkGroupConflicts(ctx, channel.ID, *input.GroupIDs); err != nil {
+			return err
+		}
+		channel.GroupIDs = *input.GroupIDs
+	}
+	if input.ModelPricing != nil {
+		channel.ModelPricing = *input.ModelPricing
+	}
+	if input.ModelMapping != nil {
+		channel.ModelMapping = input.ModelMapping
+	}
+	if input.BillingModelSource != "" {
+		channel.BillingModelSource = input.BillingModelSource
+	}
+	if input.FeaturesConfig != nil {
+		channel.FeaturesConfig = input.FeaturesConfig
+	}
+	return nil
+}
+
+// checkGroupConflicts 检查待关联的分组是否已属于其他渠道。
+// channelID 为当前渠道 ID（Create 时传 0）。
+func (s *ChannelService) checkGroupConflicts(ctx context.Context, channelID int64, groupIDs []int64) error {
+	if len(groupIDs) == 0 {
+		return nil
+	}
+	conflicting, err := s.repo.GetGroupsInOtherChannels(ctx, channelID, groupIDs)
+	if err != nil {
+		return fmt.Errorf("check group conflicts: %w", err)
+	}
+	if len(conflicting) > 0 {
+		return ErrGroupAlreadyInChannel
+	}
+	return nil
+}
+
+// getOldGroupIDs 获取渠道更新前的关联分组 ID（用于失效 auth 缓存）。
+func (s *ChannelService) getOldGroupIDs(ctx context.Context, channelID int64) []int64 {
+	if s.authCacheInvalidator == nil {
+		return nil
+	}
+	oldGroupIDs, err := s.repo.GetGroupIDs(ctx, channelID)
+	if err != nil {
+		slog.Warn("failed to get old group IDs for cache invalidation", "channel_id", channelID, "error", err)
+	}
+	return oldGroupIDs
+}
+
+// invalidateAuthCacheForGroups 对新旧分组去重后逐个失效 auth 缓存。
+func (s *ChannelService) invalidateAuthCacheForGroups(ctx context.Context, groupIDSets ...[]int64) {
+	if s.authCacheInvalidator == nil {
+		return
+	}
+	seen := make(map[int64]struct{})
+	for _, ids := range groupIDSets {
+		for _, gid := range ids {
+			if _, ok := seen[gid]; ok {
+				continue
+			}
+			seen[gid] = struct{}{}
+			s.authCacheInvalidator.InvalidateAuthCacheByGroupID(ctx, gid)
+		}
+	}
+}
+
 // Delete 删除渠道
 func (s *ChannelService) Delete(ctx context.Context, id int64) error {
-	// 先获取关联分组用于失效缓存
 	groupIDs, err := s.repo.GetGroupIDs(ctx, id)
 	if err != nil {
 		slog.Warn("failed to get group IDs before delete", "channel_id", id, "error", err)
@@ -729,12 +817,7 @@ func (s *ChannelService) Delete(ctx context.Context, id int64) error {
 	}

 	s.invalidateCache()
-
-	if s.authCacheInvalidator != nil {
-		for _, gid := range groupIDs {
-			s.authCacheInvalidator.InvalidateAuthCacheByGroupID(ctx, gid)
-		}
-	}
+	s.invalidateAuthCacheForGroups(ctx, groupIDs)

 	return nil
 }
@@ -847,6 +930,7 @@ type CreateChannelInput struct {
 	BillingModelSource string
 	RestrictModels     bool
 	Features           string
+	FeaturesConfig     map[string]any
 }

 // UpdateChannelInput 更新渠道输入
@@ -860,4 +944,5 @@ type UpdateChannelInput struct {
 	BillingModelSource string
 	RestrictModels     *bool
 	Features           *string
+	FeaturesConfig     map[string]any
 }
--- a/backend/internal/service/channel_websearch_test.go
+++ b/backend/internal/service/channel_websearch_test.go
@@ -0,0 +1,62 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestChannel_IsWebSearchEmulationEnabled_Enabled(t *testing.T) {
+	c := &Channel{
+		FeaturesConfig: map[string]any{
+			featureKeyWebSearchEmulation: map[string]any{"anthropic": true},
+		},
+	}
+	require.True(t, c.IsWebSearchEmulationEnabled("anthropic"))
+}
+
+func TestChannel_IsWebSearchEmulationEnabled_DifferentPlatform(t *testing.T) {
+	c := &Channel{
+		FeaturesConfig: map[string]any{
+			featureKeyWebSearchEmulation: map[string]any{"anthropic": true},
+		},
+	}
+	require.False(t, c.IsWebSearchEmulationEnabled("openai"))
+}
+
+func TestChannel_IsWebSearchEmulationEnabled_Disabled(t *testing.T) {
+	c := &Channel{
+		FeaturesConfig: map[string]any{
+			featureKeyWebSearchEmulation: map[string]any{"anthropic": false},
+		},
+	}
+	require.False(t, c.IsWebSearchEmulationEnabled("anthropic"))
+}
+
+func TestChannel_IsWebSearchEmulationEnabled_NilFeaturesConfig(t *testing.T) {
+	c := &Channel{FeaturesConfig: nil}
+	require.False(t, c.IsWebSearchEmulationEnabled("anthropic"))
+}
+
+func TestChannel_IsWebSearchEmulationEnabled_NilChannel(t *testing.T) {
+	var c *Channel
+	require.False(t, c.IsWebSearchEmulationEnabled("anthropic"))
+}
+
+func TestChannel_IsWebSearchEmulationEnabled_WrongStructure(t *testing.T) {
+	c := &Channel{
+		FeaturesConfig: map[string]any{
+			featureKeyWebSearchEmulation: true, // not a map
+		},
+	}
+	require.False(t, c.IsWebSearchEmulationEnabled("anthropic"))
+}
+
+func TestChannel_IsWebSearchEmulationEnabled_PlatformValueNotBool(t *testing.T) {
+	c := &Channel{
+		FeaturesConfig: map[string]any{
+			featureKeyWebSearchEmulation: map[string]any{"anthropic": "yes"},
+		},
+	}
+	require.False(t, c.IsWebSearchEmulationEnabled("anthropic"))
+}
--- a/backend/internal/service/domain_constants.go
+++ b/backend/internal/service/domain_constants.go
@@ -249,6 +249,10 @@ const (
 	SettingKeyEnableMetadataPassthrough = "enable_metadata_passthrough"
 	// SettingKeyEnableCCHSigning 是否对 billing header 中的 cch 进行 xxHash64 签名（默认 false）
 	SettingKeyEnableCCHSigning = "enable_cch_signing"
+
+	// Web Search Emulation
+	// SettingKeyWebSearchEmulationConfig 全局 web search 模拟配置（JSON）
+	SettingKeyWebSearchEmulationConfig = "web_search_emulation_config"
 )

 // AdminAPIKeyPrefix is the prefix for admin API keys (distinct from user "sk-" keys).
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -3785,6 +3785,11 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 		return nil, fmt.Errorf("parse request: empty request")
 	}

+	// Web Search 模拟：纯 web_search 请求时，直接调用搜索 API 构造响应
+	if account != nil && s.shouldEmulateWebSearch(ctx, account, parsed.Body) {
+		return s.handleWebSearchEmulation(ctx, c, account, parsed)
+	}
+
 	if account != nil && account.IsAnthropicAPIKeyPassthroughEnabled() {
 		passthroughBody := parsed.Body
 		passthroughModel := parsed.Model
--- a/backend/internal/service/gateway_websearch_emulation.go
+++ b/backend/internal/service/gateway_websearch_emulation.go
@@ -0,0 +1,358 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/websearch"
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/tidwall/gjson"
+)
+
+// Web search emulation constants
+const (
+	toolTypeWebSearchPrefix = "web_search"
+	toolTypeGoogleSearch    = "google_search"
+	toolNameWebSearch       = "web_search"
+	toolNameGoogleSearch    = "google_search"
+	toolNameWebSearch2025   = "web_search_20250305"
+
+	webSearchDefaultMaxResults = 5
+	defaultWebSearchModel      = "claude-sonnet-4-6"
+	webSearchMsgIDPrefix       = "msg_ws_"
+	webSearchToolUseIDPrefix   = "srvtoolu_ws_"
+	tokenEstimateDivisor       = 4
+
+	// featureKeyWebSearchEmulation is the key used in Account.Extra and Channel.FeaturesConfig.
+	featureKeyWebSearchEmulation = "web_search_emulation"
+)
+
+// webSearchManagerPtr stores *websearch.Manager atomically for concurrent safety.
+var webSearchManagerPtr atomic.Pointer[websearch.Manager]
+
+// SetWebSearchManager wires the websearch.Manager into the gateway (goroutine-safe).
+func SetWebSearchManager(m *websearch.Manager) {
+	webSearchManagerPtr.Store(m)
+}
+
+func getWebSearchManager() *websearch.Manager {
+	return webSearchManagerPtr.Load()
+}
+
+// shouldEmulateWebSearch checks whether a request should be intercepted.
+//
+// Judgment chain: manager exists → only web_search tool → global enabled → account enabled.
+// Note: channel-level control is enforced via the account's extra field; the channel toggle
+// in the admin UI sets the account's flag for all accounts in that channel's groups.
+func (s *GatewayService) shouldEmulateWebSearch(ctx context.Context, account *Account, body []byte) bool {
+	if getWebSearchManager() == nil {
+		return false
+	}
+	if !isOnlyWebSearchToolInBody(body) {
+		return false
+	}
+	if !s.settingService.IsWebSearchEmulationEnabled(ctx) {
+		return false
+	}
+	if !account.IsWebSearchEmulationEnabled() {
+		return false
+	}
+	return true
+}
+
+// isOnlyWebSearchToolInBody checks if the body contains exactly one web_search tool.
+func isOnlyWebSearchToolInBody(body []byte) bool {
+	tools := gjson.GetBytes(body, "tools")
+	if !tools.IsArray() {
+		return false
+	}
+	arr := tools.Array()
+	if len(arr) != 1 {
+		return false
+	}
+	return isWebSearchToolJSON(arr[0])
+}
+
+func isWebSearchToolJSON(tool gjson.Result) bool {
+	toolType := tool.Get("type").String()
+	if strings.HasPrefix(toolType, toolTypeWebSearchPrefix) || toolType == toolTypeGoogleSearch {
+		return true
+	}
+	switch tool.Get("name").String() {
+	case toolNameWebSearch, toolNameGoogleSearch, toolNameWebSearch2025:
+		return true
+	}
+	return false
+}
+
+// extractSearchQueryFromBody extracts the last user message text as the search query.
+func extractSearchQueryFromBody(body []byte) string {
+	messages := gjson.GetBytes(body, "messages")
+	if !messages.IsArray() {
+		return ""
+	}
+	arr := messages.Array()
+	if len(arr) == 0 {
+		return ""
+	}
+	lastMsg := arr[len(arr)-1]
+	if lastMsg.Get("role").String() != "user" {
+		return ""
+	}
+	return extractWebSearchTextFromContent(lastMsg.Get("content"))
+}
+
+func extractWebSearchTextFromContent(content gjson.Result) string {
+	if content.Type == gjson.String {
+		return content.String()
+	}
+	if content.IsArray() {
+		for _, block := range content.Array() {
+			if block.Get("type").String() == "text" {
+				if text := block.Get("text").String(); text != "" {
+					return text
+				}
+			}
+		}
+	}
+	return ""
+}
+
+// handleWebSearchEmulation intercepts a web-search-only request,
+// calls a third-party search API, and constructs an Anthropic-format response.
+func (s *GatewayService) handleWebSearchEmulation(
+	ctx context.Context, c *gin.Context, account *Account, parsed *ParsedRequest,
+) (*ForwardResult, error) {
+	startTime := time.Now()
+
+	// Release the serial queue lock immediately — we don't need upstream.
+	if parsed.OnUpstreamAccepted != nil {
+		parsed.OnUpstreamAccepted()
+	}
+
+	query := extractSearchQueryFromBody(parsed.Body)
+	if query == "" {
+		return nil, fmt.Errorf("web search emulation: no query found in messages")
+	}
+
+	slog.Info("web search emulation: executing search",
+		"account_id", account.ID, "account_name", account.Name, "query", query)
+
+	resp, providerName, err := doWebSearch(ctx, account, query)
+	if err != nil {
+		return nil, err
+	}
+
+	slog.Info("web search emulation: search completed",
+		"provider", providerName, "results_count", len(resp.Results))
+
+	model := parsed.Model
+	if model == "" {
+		model = defaultWebSearchModel
+	}
+
+	if parsed.Stream {
+		return writeWebSearchStreamResponse(c, query, resp, model, startTime)
+	}
+	return writeWebSearchNonStreamResponse(c, query, resp, model, startTime)
+}
+
+func doWebSearch(ctx context.Context, account *Account, query string) (*websearch.SearchResponse, string, error) {
+	proxyURL := resolveAccountProxyURL(account)
+	mgr := getWebSearchManager()
+	if mgr == nil {
+		return nil, "", fmt.Errorf("web search emulation: manager not initialized")
+	}
+	resp, providerName, err := mgr.SearchWithBestProvider(ctx, websearch.SearchRequest{
+		Query: query, MaxResults: webSearchDefaultMaxResults, ProxyURL: proxyURL,
+	})
+	if err != nil {
+		slog.Error("web search emulation: search failed", "error", err)
+		return nil, "", fmt.Errorf("web search emulation: %w", err)
+	}
+	return resp, providerName, nil
+}
+
+func resolveAccountProxyURL(account *Account) string {
+	if account.ProxyID != nil && account.Proxy != nil {
+		return account.Proxy.URL()
+	}
+	return ""
+}
+
+// --- SSE streaming response ---
+
+func writeWebSearchStreamResponse(
+	c *gin.Context, query string, resp *websearch.SearchResponse, model string, startTime time.Time,
+) (*ForwardResult, error) {
+	msgID := webSearchMsgIDPrefix + uuid.New().String()
+	toolUseID := webSearchToolUseIDPrefix + uuid.New().String()[:16]
+
+	setSSEHeaders(c)
+	if err := writeSSEMessageStart(c.Writer, msgID, model); err != nil {
+		return nil, fmt.Errorf("web search emulation: SSE write: %w", err)
+	}
+	writeSSEServerToolUse(c.Writer, toolUseID, query, 0)
+	writeSSEToolResult(c.Writer, toolUseID, resp.Results, 1)
+	textSummary := buildTextSummary(query, resp.Results)
+	writeSSETextBlock(c.Writer, textSummary, 2)
+	writeSSEMessageEnd(c.Writer, len(textSummary)/tokenEstimateDivisor)
+	c.Writer.Flush()
+
+	return &ForwardResult{Model: model, Duration: time.Since(startTime), Usage: ClaudeUsage{}}, nil
+}
+
+func setSSEHeaders(c *gin.Context) {
+	c.Writer.Header().Set("Content-Type", "text/event-stream")
+	c.Writer.Header().Set("Cache-Control", "no-cache")
+	c.Writer.Header().Set("Connection", "keep-alive")
+	c.Writer.Header().Set("X-Accel-Buffering", "no")
+	c.Writer.WriteHeader(http.StatusOK)
+}
+
+func writeSSEMessageStart(w http.ResponseWriter, msgID, model string) error {
+	evt := map[string]any{
+		"type": "message_start",
+		"message": map[string]any{
+			"id": msgID, "type": "message", "role": "assistant", "model": model,
+			"content": []any{}, "stop_reason": nil, "stop_sequence": nil,
+			"usage": map[string]int{"input_tokens": 0, "output_tokens": 0},
+		},
+	}
+	return flushSSEJSON(w, "message_start", evt)
+}
+
+func writeSSEServerToolUse(w http.ResponseWriter, toolUseID, query string, index int) {
+	start := map[string]any{
+		"type": "content_block_start", "index": index,
+		"content_block": map[string]any{
+			"type": "server_tool_use", "id": toolUseID,
+			"name": toolNameWebSearch, "input": map[string]string{"query": query},
+		},
+	}
+	_ = flushSSEJSON(w, "content_block_start", start)
+	_ = flushSSEJSON(w, "content_block_stop", map[string]any{"type": "content_block_stop", "index": index})
+}
+
+func writeSSEToolResult(w http.ResponseWriter, toolUseID string, results []websearch.SearchResult, index int) {
+	start := map[string]any{
+		"type": "content_block_start", "index": index,
+		"content_block": map[string]any{
+			"type": "web_search_tool_result", "tool_use_id": toolUseID,
+			"content": buildSearchResultBlocks(results),
+		},
+	}
+	_ = flushSSEJSON(w, "content_block_start", start)
+	_ = flushSSEJSON(w, "content_block_stop", map[string]any{"type": "content_block_stop", "index": index})
+}
+
+func writeSSETextBlock(w http.ResponseWriter, text string, index int) {
+	_ = flushSSEJSON(w, "content_block_start", map[string]any{
+		"type": "content_block_start", "index": index,
+		"content_block": map[string]any{"type": "text", "text": ""},
+	})
+	_ = flushSSEJSON(w, "content_block_delta", map[string]any{
+		"type": "content_block_delta", "index": index,
+		"delta": map[string]string{"type": "text_delta", "text": text},
+	})
+	_ = flushSSEJSON(w, "content_block_stop", map[string]any{"type": "content_block_stop", "index": index})
+}
+
+func writeSSEMessageEnd(w http.ResponseWriter, outputTokens int) {
+	_ = flushSSEJSON(w, "message_delta", map[string]any{
+		"type":  "message_delta",
+		"delta": map[string]any{"stop_reason": "end_turn", "stop_sequence": nil},
+		"usage": map[string]int{"output_tokens": outputTokens},
+	})
+	_ = flushSSEJSON(w, "message_stop", map[string]string{"type": "message_stop"})
+}
+
+// flushSSEJSON marshals data to JSON and writes an SSE event. Returns error on marshal failure.
+func flushSSEJSON(w http.ResponseWriter, event string, data any) error {
+	b, err := json.Marshal(data)
+	if err != nil {
+		slog.Error("web search emulation: failed to marshal SSE event",
+			"event", event, "error", err)
+		return err
+	}
+	fmt.Fprintf(w, "event: %s\ndata: %s\n\n", event, b)
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+	return nil
+}
+
+// --- Non-streaming JSON response ---
+
+func writeWebSearchNonStreamResponse(
+	c *gin.Context, query string, resp *websearch.SearchResponse, model string, startTime time.Time,
+) (*ForwardResult, error) {
+	msgID := webSearchMsgIDPrefix + uuid.New().String()
+	toolUseID := webSearchToolUseIDPrefix + uuid.New().String()[:16]
+	textSummary := buildTextSummary(query, resp.Results)
+
+	msg := map[string]any{
+		"id": msgID, "type": "message", "role": "assistant", "model": model,
+		"content": []any{
+			map[string]any{
+				"type": "server_tool_use", "id": toolUseID,
+				"name": toolNameWebSearch, "input": map[string]string{"query": query},
+			},
+			map[string]any{
+				"type": "web_search_tool_result", "tool_use_id": toolUseID,
+				"content": buildSearchResultBlocks(resp.Results),
+			},
+			map[string]any{"type": "text", "text": textSummary},
+		},
+		"stop_reason": "end_turn", "stop_sequence": nil,
+		"usage": map[string]int{"input_tokens": 0, "output_tokens": len(textSummary) / tokenEstimateDivisor},
+	}
+
+	body, err := json.Marshal(msg)
+	if err != nil {
+		return nil, fmt.Errorf("web search emulation: marshal response: %w", err)
+	}
+	c.Data(http.StatusOK, "application/json", body)
+
+	return &ForwardResult{Model: model, Duration: time.Since(startTime), Usage: ClaudeUsage{}}, nil
+}
+
+// --- Helpers ---
+
+func buildSearchResultBlocks(results []websearch.SearchResult) []map[string]string {
+	blocks := make([]map[string]string, 0, len(results))
+	for _, r := range results {
+		block := map[string]string{
+			"type":  "web_search_result",
+			"url":   r.URL,
+			"title": r.Title,
+		}
+		if r.Snippet != "" {
+			block["page_content"] = r.Snippet
+		}
+		if r.PageAge != "" {
+			block["page_age"] = r.PageAge
+		}
+		blocks = append(blocks, block)
+	}
+	return blocks
+}
+
+func buildTextSummary(query string, results []websearch.SearchResult) string {
+	if len(results) == 0 {
+		return "No search results found for: " + query
+	}
+	var sb strings.Builder
+	fmt.Fprintf(&sb, "Here are the search results for \"%s\":\n\n", query)
+	for i, r := range results {
+		fmt.Fprintf(&sb, "%d. **%s**\n   %s\n   %s\n\n", i+1, r.Title, r.URL, r.Snippet)
+	}
+	return sb.String()
+}
--- a/backend/internal/service/gateway_websearch_emulation_test.go
+++ b/backend/internal/service/gateway_websearch_emulation_test.go
@@ -0,0 +1,142 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/websearch"
+	"github.com/stretchr/testify/require"
+)
+
+// --- isOnlyWebSearchToolInBody ---
+
+func TestIsOnlyWebSearchToolInBody_WebSearchType(t *testing.T) {
+	require.True(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"type":"web_search"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_WebSearch2025Type(t *testing.T) {
+	require.True(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"type":"web_search_20250305"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_GoogleSearchType(t *testing.T) {
+	require.True(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"type":"google_search"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_NameWebSearch(t *testing.T) {
+	require.True(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"name":"web_search"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_NameWebSearch2025(t *testing.T) {
+	require.True(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"name":"web_search_20250305"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_NameGoogleSearch(t *testing.T) {
+	require.True(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"name":"google_search"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_MultipleTools(t *testing.T) {
+	require.False(t, isOnlyWebSearchToolInBody(
+		[]byte(`{"tools":[{"type":"web_search"},{"type":"text_editor"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_NoTools(t *testing.T) {
+	require.False(t, isOnlyWebSearchToolInBody([]byte(`{"model":"claude-3"}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_EmptyToolsArray(t *testing.T) {
+	require.False(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_NonWebSearchTool(t *testing.T) {
+	require.False(t, isOnlyWebSearchToolInBody([]byte(`{"tools":[{"type":"text_editor"}]}`)))
+}
+
+func TestIsOnlyWebSearchToolInBody_ToolsNotArray(t *testing.T) {
+	require.False(t, isOnlyWebSearchToolInBody([]byte(`{"tools":"web_search"}`)))
+}
+
+// --- extractSearchQueryFromBody ---
+
+func TestExtractSearchQueryFromBody_StringContent(t *testing.T) {
+	body := `{"messages":[{"role":"user","content":"what is golang"}]}`
+	require.Equal(t, "what is golang", extractSearchQueryFromBody([]byte(body)))
+}
+
+func TestExtractSearchQueryFromBody_ArrayContent(t *testing.T) {
+	body := `{"messages":[{"role":"user","content":[{"type":"text","text":"search this"}]}]}`
+	require.Equal(t, "search this", extractSearchQueryFromBody([]byte(body)))
+}
+
+func TestExtractSearchQueryFromBody_MultipleMessages(t *testing.T) {
+	body := `{"messages":[{"role":"user","content":"first"},{"role":"assistant","content":"ok"},{"role":"user","content":"second"}]}`
+	require.Equal(t, "second", extractSearchQueryFromBody([]byte(body)))
+}
+
+func TestExtractSearchQueryFromBody_LastMessageNotUser(t *testing.T) {
+	body := `{"messages":[{"role":"user","content":"q"},{"role":"assistant","content":"a"}]}`
+	require.Equal(t, "", extractSearchQueryFromBody([]byte(body)))
+}
+
+func TestExtractSearchQueryFromBody_EmptyMessages(t *testing.T) {
+	require.Equal(t, "", extractSearchQueryFromBody([]byte(`{"messages":[]}`)))
+}
+
+func TestExtractSearchQueryFromBody_NoMessages(t *testing.T) {
+	require.Equal(t, "", extractSearchQueryFromBody([]byte(`{"model":"claude-3"}`)))
+}
+
+func TestExtractSearchQueryFromBody_ArrayContentSkipsEmptyText(t *testing.T) {
+	body := `{"messages":[{"role":"user","content":[{"type":"image"},{"type":"text","text":""},{"type":"text","text":"real query"}]}]}`
+	require.Equal(t, "real query", extractSearchQueryFromBody([]byte(body)))
+}
+
+func TestExtractSearchQueryFromBody_ArrayContentNoTextBlock(t *testing.T) {
+	body := `{"messages":[{"role":"user","content":[{"type":"image","source":{}}]}]}`
+	require.Equal(t, "", extractSearchQueryFromBody([]byte(body)))
+}
+
+// --- buildSearchResultBlocks ---
+
+func TestBuildSearchResultBlocks_WithResults(t *testing.T) {
+	results := []websearch.SearchResult{
+		{URL: "https://a.com", Title: "A", Snippet: "snippet a", PageAge: "2 days"},
+		{URL: "https://b.com", Title: "B", Snippet: "snippet b"},
+	}
+	blocks := buildSearchResultBlocks(results)
+	require.Len(t, blocks, 2)
+	require.Equal(t, "web_search_result", blocks[0]["type"])
+	require.Equal(t, "https://a.com", blocks[0]["url"])
+	require.Equal(t, "snippet a", blocks[0]["page_content"])
+	require.Equal(t, "2 days", blocks[0]["page_age"])
+	// Second result has no PageAge
+	require.Equal(t, "https://b.com", blocks[1]["url"])
+	_, hasPageAge := blocks[1]["page_age"]
+	require.False(t, hasPageAge)
+}
+
+func TestBuildSearchResultBlocks_Empty(t *testing.T) {
+	blocks := buildSearchResultBlocks(nil)
+	require.Empty(t, blocks)
+}
+
+func TestBuildSearchResultBlocks_SnippetEmpty(t *testing.T) {
+	blocks := buildSearchResultBlocks([]websearch.SearchResult{{URL: "https://x.com", Title: "X", Snippet: ""}})
+	_, hasContent := blocks[0]["page_content"]
+	require.False(t, hasContent)
+}
+
+// --- buildTextSummary ---
+
+func TestBuildTextSummary_WithResults(t *testing.T) {
+	results := []websearch.SearchResult{
+		{URL: "https://a.com", Title: "A", Snippet: "desc a"},
+	}
+	summary := buildTextSummary("test query", results)
+	require.Contains(t, summary, "test query")
+	require.Contains(t, summary, "1. **A**")
+	require.Contains(t, summary, "https://a.com")
+}
+
+func TestBuildTextSummary_NoResults(t *testing.T) {
+	summary := buildTextSummary("test", nil)
+	require.Contains(t, summary, "No search results found for: test")
+}
--- a/backend/internal/service/setting_service.go
+++ b/backend/internal/service/setting_service.go
@@ -18,6 +18,7 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/config"
 	infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
 	"github.com/imroc/req/v3"
+	"github.com/redis/go-redis/v9"
 	"golang.org/x/sync/singleflight"
 )

@@ -106,6 +107,7 @@ type SettingService struct {
 	cfg                   *config.Config
 	onUpdate              func() // Callback when settings are updated (for cache invalidation)
 	version               string // Application version
+	webSearchRedis        *redis.Client // optional: Redis client for web search quota tracking
 }

 // NewSettingService 创建系统设置服务实例
@@ -1217,6 +1219,14 @@ func (s *SettingService) parseSettings(settings map[string]string) *SystemSettin
 	result.EnableMetadataPassthrough = settings[SettingKeyEnableMetadataPassthrough] == "true"
 	result.EnableCCHSigning = settings[SettingKeyEnableCCHSigning] == "true"

+	// Web search emulation: quick enabled check from the JSON config
+	if raw := settings[SettingKeyWebSearchEmulationConfig]; raw != "" {
+		var wsCfg WebSearchEmulationConfig
+		if err := json.Unmarshal([]byte(raw), &wsCfg); err == nil {
+			result.WebSearchEmulationEnabled = wsCfg.Enabled && len(wsCfg.Providers) > 0
+		}
+	}
+
 	return result
 }

--- a/backend/internal/service/settings_view.go
+++ b/backend/internal/service/settings_view.go
@@ -106,6 +106,9 @@ type SystemSettings struct {
 	EnableFingerprintUnification bool // 是否统一 OAuth 账号的指纹头（默认 true）
 	EnableMetadataPassthrough    bool // 是否透传客户端原始 metadata（默认 false）
 	EnableCCHSigning             bool // 是否对 billing header cch 进行签名（默认 false）
+
+	// Web Search Emulation (read-only quick check; full config via dedicated API)
+	WebSearchEmulationEnabled bool
 }

 type DefaultSubscriptionSetting struct {
--- a/backend/internal/service/websearch_config.go
+++ b/backend/internal/service/websearch_config.go
@@ -0,0 +1,253 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"sync/atomic"
+	"time"
+
+	infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/websearch"
+	"github.com/redis/go-redis/v9"
+	"golang.org/x/sync/singleflight"
+)
+
+// WebSearchEmulationConfig holds the global web search emulation configuration.
+type WebSearchEmulationConfig struct {
+	Enabled   bool                      `json:"enabled"`
+	Providers []WebSearchProviderConfig `json:"providers"`
+}
+
+// WebSearchProviderConfig describes a single search provider (Brave or Tavily).
+type WebSearchProviderConfig struct {
+	Type                 string `json:"type"`                   // websearch.ProviderTypeBrave | Tavily
+	APIKey               string `json:"api_key,omitempty"`      // secret — omitted in API responses
+	APIKeyConfigured     bool   `json:"api_key_configured"`     // read-only mask
+	Priority             int    `json:"priority"`               // lower = higher priority
+	QuotaLimit           int64  `json:"quota_limit"`            // 0 = unlimited
+	QuotaRefreshInterval string `json:"quota_refresh_interval"` // websearch.QuotaRefresh*
+	QuotaUsed            int64  `json:"quota_used,omitempty"`   // read-only: current period usage
+	ProxyID              *int64 `json:"proxy_id"`               // optional proxy association
+	ExpiresAt            *int64 `json:"expires_at,omitempty"`   // optional expiration timestamp
+}
+
+// --- Validation ---
+
+const maxWebSearchProviders = 10
+
+var validProviderTypes = map[string]bool{
+	websearch.ProviderTypeBrave:  true,
+	websearch.ProviderTypeTavily: true,
+}
+
+var validQuotaIntervals = map[string]bool{
+	websearch.QuotaRefreshDaily:   true,
+	websearch.QuotaRefreshWeekly:  true,
+	websearch.QuotaRefreshMonthly: true,
+	"":                            true, // defaults to monthly
+}
+
+func validateWebSearchConfig(cfg *WebSearchEmulationConfig) error {
+	if cfg == nil {
+		return nil
+	}
+	if len(cfg.Providers) > maxWebSearchProviders {
+		return fmt.Errorf("too many providers (max %d)", maxWebSearchProviders)
+	}
+	seen := make(map[string]bool, len(cfg.Providers))
+	for i, p := range cfg.Providers {
+		if !validProviderTypes[p.Type] {
+			return fmt.Errorf("provider[%d]: invalid type %q", i, p.Type)
+		}
+		if !validQuotaIntervals[p.QuotaRefreshInterval] {
+			return fmt.Errorf("provider[%d]: invalid quota_refresh_interval %q", i, p.QuotaRefreshInterval)
+		}
+		if p.QuotaLimit < 0 {
+			return fmt.Errorf("provider[%d]: quota_limit must be >= 0", i)
+		}
+		if seen[p.Type] {
+			return fmt.Errorf("provider[%d]: duplicate type %q", i, p.Type)
+		}
+		seen[p.Type] = true
+	}
+	return nil
+}
+
+// --- In-process cache (same pattern as gateway forwarding settings) ---
+
+const sfKeyWebSearchConfig = "web_search_emulation_config"
+
+type cachedWebSearchEmulationConfig struct {
+	config    *WebSearchEmulationConfig
+	expiresAt int64 // unix nano
+}
+
+var webSearchEmulationCache atomic.Value // *cachedWebSearchEmulationConfig
+var webSearchEmulationSF singleflight.Group
+
+const (
+	webSearchEmulationCacheTTL  = 60 * time.Second
+	webSearchEmulationErrorTTL  = 5 * time.Second
+	webSearchEmulationDBTimeout = 5 * time.Second
+)
+
+// GetWebSearchEmulationConfig returns the configuration with in-process cache + singleflight.
+func (s *SettingService) GetWebSearchEmulationConfig(ctx context.Context) (*WebSearchEmulationConfig, error) {
+	if cached := webSearchEmulationCache.Load(); cached != nil {
+		c := cached.(*cachedWebSearchEmulationConfig)
+		if time.Now().UnixNano() < c.expiresAt {
+			return c.config, nil
+		}
+	}
+	result, err, _ := webSearchEmulationSF.Do(sfKeyWebSearchConfig, func() (any, error) {
+		return s.loadWebSearchConfigFromDB()
+	})
+	if err != nil {
+		return &WebSearchEmulationConfig{}, err
+	}
+	return result.(*WebSearchEmulationConfig), nil
+}
+
+func (s *SettingService) loadWebSearchConfigFromDB() (*WebSearchEmulationConfig, error) {
+	dbCtx, cancel := context.WithTimeout(context.Background(), webSearchEmulationDBTimeout)
+	defer cancel()
+
+	raw, err := s.settingRepo.GetValue(dbCtx, SettingKeyWebSearchEmulationConfig)
+	if err != nil {
+		webSearchEmulationCache.Store(&cachedWebSearchEmulationConfig{
+			config:    &WebSearchEmulationConfig{},
+			expiresAt: time.Now().Add(webSearchEmulationErrorTTL).UnixNano(),
+		})
+		return &WebSearchEmulationConfig{}, err
+	}
+	cfg := parseWebSearchConfigJSON(raw)
+	webSearchEmulationCache.Store(&cachedWebSearchEmulationConfig{
+		config:    cfg,
+		expiresAt: time.Now().Add(webSearchEmulationCacheTTL).UnixNano(),
+	})
+	return cfg, nil
+}
+
+func parseWebSearchConfigJSON(raw string) *WebSearchEmulationConfig {
+	cfg := &WebSearchEmulationConfig{}
+	if raw == "" {
+		return cfg
+	}
+	if err := json.Unmarshal([]byte(raw), cfg); err != nil {
+		slog.Warn("websearch: failed to parse config JSON", "error", err)
+		return &WebSearchEmulationConfig{}
+	}
+	return cfg
+}
+
+// SaveWebSearchEmulationConfig validates and persists the configuration.
+// Empty API keys in the input are preserved from the existing config.
+func (s *SettingService) SaveWebSearchEmulationConfig(ctx context.Context, cfg *WebSearchEmulationConfig) error {
+	if err := validateWebSearchConfig(cfg); err != nil {
+		return infraerrors.BadRequest("INVALID_WEB_SEARCH_CONFIG", err.Error())
+	}
+	s.mergeExistingAPIKeys(ctx, cfg)
+
+	data, err := json.Marshal(cfg)
+	if err != nil {
+		return fmt.Errorf("websearch: marshal config: %w", err)
+	}
+	if err := s.settingRepo.Set(ctx, SettingKeyWebSearchEmulationConfig, string(data)); err != nil {
+		return fmt.Errorf("websearch: save config: %w", err)
+	}
+	// Invalidate: forget singleflight first, then store new value
+	webSearchEmulationSF.Forget(sfKeyWebSearchConfig)
+	webSearchEmulationCache.Store(&cachedWebSearchEmulationConfig{
+		config:    cfg,
+		expiresAt: time.Now().Add(webSearchEmulationCacheTTL).UnixNano(),
+	})
+
+	// Hot-reload: rebuild the global Manager with new config
+	s.RebuildWebSearchManager(ctx)
+	return nil
+}
+
+// mergeExistingAPIKeys preserves API keys from the current config when incoming value is empty.
+func (s *SettingService) mergeExistingAPIKeys(ctx context.Context, cfg *WebSearchEmulationConfig) {
+	existing, _ := s.getWebSearchEmulationConfigRaw(ctx)
+	if existing == nil || cfg == nil {
+		return
+	}
+	existingByType := make(map[string]string, len(existing.Providers))
+	for _, p := range existing.Providers {
+		if p.APIKey != "" {
+			existingByType[p.Type] = p.APIKey
+		}
+	}
+	for i := range cfg.Providers {
+		if cfg.Providers[i].APIKey == "" {
+			if key, ok := existingByType[cfg.Providers[i].Type]; ok {
+				cfg.Providers[i].APIKey = key
+			}
+		}
+	}
+}
+
+func (s *SettingService) getWebSearchEmulationConfigRaw(ctx context.Context) (*WebSearchEmulationConfig, error) {
+	raw, err := s.settingRepo.GetValue(ctx, SettingKeyWebSearchEmulationConfig)
+	if err != nil {
+		return nil, err
+	}
+	return parseWebSearchConfigJSON(raw), nil
+}
+
+// IsWebSearchEmulationEnabled is a quick check for whether the global switch is on.
+func (s *SettingService) IsWebSearchEmulationEnabled(ctx context.Context) bool {
+	cfg, err := s.GetWebSearchEmulationConfig(ctx)
+	if err != nil {
+		return false
+	}
+	return cfg.Enabled && len(cfg.Providers) > 0
+}
+
+// SetWebSearchRedisClient injects the Redis client used for quota tracking.
+// Call after construction, before first use. Triggers initial Manager build.
+func (s *SettingService) SetWebSearchRedisClient(ctx context.Context, redisClient *redis.Client) {
+	s.webSearchRedis = redisClient
+	s.RebuildWebSearchManager(ctx)
+}
+
+// RebuildWebSearchManager reads the current config and (re)creates the global websearch.Manager.
+// Called on startup and after SaveWebSearchEmulationConfig.
+func (s *SettingService) RebuildWebSearchManager(ctx context.Context) {
+	cfg, err := s.GetWebSearchEmulationConfig(ctx)
+	if err != nil || !cfg.Enabled || len(cfg.Providers) == 0 {
+		SetWebSearchManager(nil)
+		return
+	}
+	providerConfigs := make([]websearch.ProviderConfig, 0, len(cfg.Providers))
+	for _, p := range cfg.Providers {
+		providerConfigs = append(providerConfigs, websearch.ProviderConfig{
+			Type:                 p.Type,
+			APIKey:               p.APIKey,
+			Priority:             p.Priority,
+			QuotaLimit:           p.QuotaLimit,
+			QuotaRefreshInterval: p.QuotaRefreshInterval,
+			ExpiresAt:            p.ExpiresAt,
+		})
+	}
+	SetWebSearchManager(websearch.NewManager(providerConfigs, s.webSearchRedis))
+	slog.Info("websearch: manager rebuilt", "provider_count", len(providerConfigs))
+}
+
+// SanitizeWebSearchConfig returns a copy with api_key fields masked for API responses.
+func SanitizeWebSearchConfig(cfg *WebSearchEmulationConfig) *WebSearchEmulationConfig {
+	if cfg == nil {
+		return nil
+	}
+	out := *cfg
+	out.Providers = make([]WebSearchProviderConfig, len(cfg.Providers))
+	for i, p := range cfg.Providers {
+		out.Providers[i] = p
+		out.Providers[i].APIKeyConfigured = p.APIKey != ""
+		out.Providers[i].APIKey = "" // never return the secret
+	}
+	return &out
+}
--- a/backend/internal/service/websearch_config_test.go
+++ b/backend/internal/service/websearch_config_test.go
@@ -0,0 +1,148 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// --- validateWebSearchConfig ---
+
+func TestValidateWebSearchConfig_Nil(t *testing.T) {
+	require.NoError(t, validateWebSearchConfig(nil))
+}
+
+func TestValidateWebSearchConfig_Valid(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Enabled: true,
+		Providers: []WebSearchProviderConfig{
+			{Type: "brave", Priority: 1, QuotaLimit: 1000, QuotaRefreshInterval: "monthly"},
+			{Type: "tavily", Priority: 2, QuotaLimit: 500, QuotaRefreshInterval: "daily"},
+		},
+	}
+	require.NoError(t, validateWebSearchConfig(cfg))
+}
+
+func TestValidateWebSearchConfig_TooManyProviders(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{Providers: make([]WebSearchProviderConfig, 11)}
+	for i := range cfg.Providers {
+		cfg.Providers[i] = WebSearchProviderConfig{Type: "brave"}
+	}
+	err := validateWebSearchConfig(cfg)
+	require.ErrorContains(t, err, "too many providers")
+}
+
+func TestValidateWebSearchConfig_InvalidType(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "bing"}},
+	}
+	require.ErrorContains(t, validateWebSearchConfig(cfg), "invalid type")
+}
+
+func TestValidateWebSearchConfig_InvalidQuotaInterval(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaRefreshInterval: "hourly"}},
+	}
+	require.ErrorContains(t, validateWebSearchConfig(cfg), "invalid quota_refresh_interval")
+}
+
+func TestValidateWebSearchConfig_NegativeQuotaLimit(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaLimit: -1}},
+	}
+	require.ErrorContains(t, validateWebSearchConfig(cfg), "quota_limit must be >= 0")
+}
+
+func TestValidateWebSearchConfig_DuplicateType(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{
+			{Type: "brave", Priority: 1},
+			{Type: "brave", Priority: 2},
+		},
+	}
+	require.ErrorContains(t, validateWebSearchConfig(cfg), "duplicate type")
+}
+
+func TestValidateWebSearchConfig_EmptyQuotaInterval(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaRefreshInterval: ""}},
+	}
+	require.NoError(t, validateWebSearchConfig(cfg))
+}
+
+func TestValidateWebSearchConfig_ZeroQuotaLimit(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "brave", QuotaLimit: 0}},
+	}
+	require.NoError(t, validateWebSearchConfig(cfg))
+}
+
+// --- parseWebSearchConfigJSON ---
+
+func TestParseWebSearchConfigJSON_ValidJSON(t *testing.T) {
+	raw := `{"enabled":true,"providers":[{"type":"brave","api_key":"sk-xxx"}]}`
+	cfg := parseWebSearchConfigJSON(raw)
+	require.True(t, cfg.Enabled)
+	require.Len(t, cfg.Providers, 1)
+	require.Equal(t, "brave", cfg.Providers[0].Type)
+}
+
+func TestParseWebSearchConfigJSON_EmptyString(t *testing.T) {
+	cfg := parseWebSearchConfigJSON("")
+	require.False(t, cfg.Enabled)
+	require.Empty(t, cfg.Providers)
+}
+
+func TestParseWebSearchConfigJSON_InvalidJSON(t *testing.T) {
+	cfg := parseWebSearchConfigJSON("not{json")
+	require.False(t, cfg.Enabled)
+	require.Empty(t, cfg.Providers)
+}
+
+// --- SanitizeWebSearchConfig ---
+
+func TestSanitizeWebSearchConfig_MaskAPIKey(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Enabled: true,
+		Providers: []WebSearchProviderConfig{
+			{Type: "brave", APIKey: "sk-secret-xxx"},
+		},
+	}
+	out := SanitizeWebSearchConfig(cfg)
+	require.Equal(t, "", out.Providers[0].APIKey)
+	require.True(t, out.Providers[0].APIKeyConfigured)
+}
+
+func TestSanitizeWebSearchConfig_NoAPIKey(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "brave", APIKey: ""}},
+	}
+	out := SanitizeWebSearchConfig(cfg)
+	require.Equal(t, "", out.Providers[0].APIKey)
+	require.False(t, out.Providers[0].APIKeyConfigured)
+}
+
+func TestSanitizeWebSearchConfig_Nil(t *testing.T) {
+	require.Nil(t, SanitizeWebSearchConfig(nil))
+}
+
+func TestSanitizeWebSearchConfig_PreservesOtherFields(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Enabled: true,
+		Providers: []WebSearchProviderConfig{
+			{Type: "brave", APIKey: "secret", Priority: 10, QuotaLimit: 1000},
+		},
+	}
+	out := SanitizeWebSearchConfig(cfg)
+	require.True(t, out.Enabled)
+	require.Equal(t, 10, out.Providers[0].Priority)
+	require.Equal(t, int64(1000), out.Providers[0].QuotaLimit)
+}
+
+func TestSanitizeWebSearchConfig_DoesNotMutateOriginal(t *testing.T) {
+	cfg := &WebSearchEmulationConfig{
+		Providers: []WebSearchProviderConfig{{Type: "brave", APIKey: "secret"}},
+	}
+	_ = SanitizeWebSearchConfig(cfg)
+	require.Equal(t, "secret", cfg.Providers[0].APIKey)
+}