fix(tools): improve web search provider fallback (#2629)

- centralize web search provider readiness and resolution logic
- fall back when the configured provider is unavailable or invalid
- allow native-search-capable models to use built-in search without the client tool
- simplify the tools page and add direct access to web search settings
- add backend, agent, and integration tests for the new selection behavior

web/backend/api/tools.go

@@ -261,6 +261,8 @@ func buildToolSupport(cfg *config.Config) []toolSupportItem {
 			status, reasonCode = resolveDiscoveryToolSupport(cfg, cfg.Tools.MCP.Discovery.UseRegex)
 		case "tool_search_tool_bm25":
 			status, reasonCode = resolveDiscoveryToolSupport(cfg, cfg.Tools.MCP.Discovery.UseBM25)
+		case "web_search":
+			status, reasonCode = resolveWebSearchToolSupport(cfg)
 		case "i2c", "spi":
 			status, reasonCode = resolveHardwareToolSupport(cfg.Tools.IsToolEnabled(entry.ConfigKey))
 		default:
@@ -304,6 +306,13 @@ func resolveDiscoveryToolSupport(cfg *config.Config, methodEnabled bool) (string
 	return "enabled", ""
 }
 
+func resolveWebSearchToolSupport(cfg *config.Config) (string, string) {
+	if !cfg.Tools.IsToolEnabled("web") {
+		return "disabled", ""
+	}
+	return "enabled", ""
+}
+
 func applyToolState(cfg *config.Config, toolName string, enabled bool) error {
 	switch toolName {
 	case "read_file":
@@ -507,6 +516,7 @@ func normalizeWebSearchAPIKeys(apiKeys []string, apiKey string) ([]string, bool)
 }
 
 func buildWebSearchConfigResponse(cfg *config.Config) webSearchConfigResponse {
+	opts := picotools.WebSearchToolOptionsFromConfig(cfg)
 	current := resolveCurrentWebSearchProvider(cfg)
 	settings := map[string]webSearchProviderConfig{
 		"sogou": {
@@ -563,59 +573,53 @@ func buildWebSearchConfigResponse(cfg *config.Config) webSearchConfigResponse {
 		{
 			ID:         "sogou",
 			Label:      "Sogou",
-			Configured: cfg.Tools.Web.Sogou.Enabled,
+			Configured: picotools.WebSearchProviderReady(opts, "sogou"),
 			Current:    current == "sogou",
 		},
 		{
 			ID:         "duckduckgo",
 			Label:      "DuckDuckGo",
-			Configured: cfg.Tools.Web.DuckDuckGo.Enabled,
+			Configured: picotools.WebSearchProviderReady(opts, "duckduckgo"),
 			Current:    current == "duckduckgo",
 		},
 		{
-			ID:    "brave",
-			Label: "Brave Search",
-			Configured: cfg.Tools.Web.Brave.Enabled &&
-				len(cfg.Tools.Web.Brave.APIKeys.Values()) > 0,
+			ID:           "brave",
+			Label:        "Brave Search",
+			Configured:   picotools.WebSearchProviderReady(opts, "brave"),
 			Current:      current == "brave",
 			RequiresAuth: true,
 		},
 		{
-			ID:    "tavily",
-			Label: "Tavily",
-			Configured: cfg.Tools.Web.Tavily.Enabled &&
-				len(cfg.Tools.Web.Tavily.APIKeys.Values()) > 0,
+			ID:           "tavily",
+			Label:        "Tavily",
+			Configured:   picotools.WebSearchProviderReady(opts, "tavily"),
 			Current:      current == "tavily",
 			RequiresAuth: true,
 		},
 		{
-			ID:    "perplexity",
-			Label: "Perplexity",
-			Configured: cfg.Tools.Web.Perplexity.Enabled &&
-				len(cfg.Tools.Web.Perplexity.APIKeys.Values()) > 0,
+			ID:           "perplexity",
+			Label:        "Perplexity",
+			Configured:   picotools.WebSearchProviderReady(opts, "perplexity"),
 			Current:      current == "perplexity",
 			RequiresAuth: true,
 		},
 		{
-			ID:    "searxng",
-			Label: "SearXNG",
-			Configured: cfg.Tools.Web.SearXNG.Enabled &&
-				strings.TrimSpace(cfg.Tools.Web.SearXNG.BaseURL) != "",
-			Current: current == "searxng",
+			ID:         "searxng",
+			Label:      "SearXNG",
+			Configured: picotools.WebSearchProviderReady(opts, "searxng"),
+			Current:    current == "searxng",
 		},
 		{
-			ID:    "glm_search",
-			Label: "GLM Search",
-			Configured: cfg.Tools.Web.GLMSearch.Enabled &&
-				cfg.Tools.Web.GLMSearch.APIKey.String() != "",
+			ID:           "glm_search",
+			Label:        "GLM Search",
+			Configured:   picotools.WebSearchProviderReady(opts, "glm_search"),
 			Current:      current == "glm_search",
 			RequiresAuth: true,
 		},
 		{
-			ID:    "baidu_search",
-			Label: "Baidu Search",
-			Configured: cfg.Tools.Web.BaiduSearch.Enabled &&
-				cfg.Tools.Web.BaiduSearch.APIKey.String() != "",
+			ID:           "baidu_search",
+			Label:        "Baidu Search",
+			Configured:   picotools.WebSearchProviderReady(opts, "baidu_search"),
 			Current:      current == "baidu_search",
 			RequiresAuth: true,
 		},
@@ -637,57 +641,12 @@ func buildWebSearchConfigResponse(cfg *config.Config) webSearchConfigResponse {
 }
 
 func resolveCurrentWebSearchProvider(cfg *config.Config) string {
-	selected := normalizeWebSearchProvider(cfg.Tools.Web.Provider)
-	if selected != "" && selected != "auto" && webSearchProviderConfigured(cfg, selected) {
-		return selected
+	if cfg == nil || !cfg.Tools.IsToolEnabled("web") {
+		return ""
 	}
-
-	for _, name := range []string{"perplexity", "brave", "searxng", "tavily"} {
-		if webSearchProviderConfigured(cfg, name) {
-			return name
-		}
-	}
-
-	if webSearchProviderConfigured(cfg, "sogou") && webSearchProviderConfigured(cfg, "duckduckgo") {
-		if picotools.GetPreferredWebSearchLanguage() == "en" {
-			return "duckduckgo"
-		}
-		return "sogou"
-	}
-	if webSearchProviderConfigured(cfg, "sogou") {
-		return "sogou"
-	}
-	if webSearchProviderConfigured(cfg, "duckduckgo") {
-		return "duckduckgo"
-	}
-
-	for _, name := range []string{"baidu_search", "glm_search"} {
-		if webSearchProviderConfigured(cfg, name) {
-			return name
-		}
-	}
-	return ""
-}
-
-func webSearchProviderConfigured(cfg *config.Config, name string) bool {
-	switch name {
-	case "sogou":
-		return cfg.Tools.Web.Sogou.Enabled
-	case "duckduckgo":
-		return cfg.Tools.Web.DuckDuckGo.Enabled
-	case "brave":
-		return cfg.Tools.Web.Brave.Enabled && len(cfg.Tools.Web.Brave.APIKeys.Values()) > 0
-	case "tavily":
-		return cfg.Tools.Web.Tavily.Enabled && len(cfg.Tools.Web.Tavily.APIKeys.Values()) > 0
-	case "perplexity":
-		return cfg.Tools.Web.Perplexity.Enabled && len(cfg.Tools.Web.Perplexity.APIKeys.Values()) > 0
-	case "searxng":
-		return cfg.Tools.Web.SearXNG.Enabled && strings.TrimSpace(cfg.Tools.Web.SearXNG.BaseURL) != ""
-	case "glm_search":
-		return cfg.Tools.Web.GLMSearch.Enabled && cfg.Tools.Web.GLMSearch.APIKey.String() != ""
-	case "baidu_search":
-		return cfg.Tools.Web.BaiduSearch.Enabled && cfg.Tools.Web.BaiduSearch.APIKey.String() != ""
-	default:
-		return false
+	selected, err := picotools.ResolveWebSearchProviderName(picotools.WebSearchToolOptionsFromConfig(cfg), "")
+	if err != nil {
+		return ""
 	}
+	return selected
 }

web/backend/api/tools_test.go

@@ -198,6 +198,66 @@ func TestHandleUpdateToolState(t *testing.T) {
 	}
 }
 
+func TestHandleListTools_ReportsWebSearchEnabledWhenToolIsOn(t *testing.T) {
+	tests := []struct {
+		name         string
+		preferNative bool
+	}{
+		{name: "without prefer_native", preferNative: false},
+		{name: "with prefer_native", preferNative: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			configPath, cleanup := setupOAuthTestEnv(t)
+			defer cleanup()
+
+			cfg, err := config.LoadConfig(configPath)
+			if err != nil {
+				t.Fatalf("LoadConfig() error = %v", err)
+			}
+			cfg.Tools.Web.PreferNative = tt.preferNative
+			cfg.Tools.Web.Provider = "brave"
+			cfg.Tools.Web.Sogou.Enabled = false
+			cfg.Tools.Web.DuckDuckGo.Enabled = false
+			cfg.Tools.Web.Brave.Enabled = true
+			cfg.Tools.Web.Brave.SetAPIKeys(nil)
+			if err := config.SaveConfig(configPath, cfg); err != nil {
+				t.Fatalf("SaveConfig() error = %v", err)
+			}
+
+			h := NewHandler(configPath)
+			mux := http.NewServeMux()
+			h.RegisterRoutes(mux)
+
+			rec := httptest.NewRecorder()
+			req := httptest.NewRequest(http.MethodGet, "/api/tools", nil)
+			mux.ServeHTTP(rec, req)
+
+			if rec.Code != http.StatusOK {
+				t.Fatalf("status = %d, want %d, body=%s", rec.Code, http.StatusOK, rec.Body.String())
+			}
+
+			var resp toolSupportResponse
+			if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
+				t.Fatalf("Unmarshal() error = %v", err)
+			}
+
+			for _, tool := range resp.Tools {
+				if tool.Name != "web_search" {
+					continue
+				}
+				if tool.Status != "enabled" || tool.ReasonCode != "" {
+					t.Fatalf("web_search = %#v, want enabled with no reason code", tool)
+				}
+				return
+			}
+
+			t.Fatal("expected web_search in response")
+		})
+	}
+}
+
 func TestHandleGetWebSearchConfig(t *testing.T) {
 	configPath, cleanup := setupOAuthTestEnv(t)
 	defer cleanup()
@@ -206,6 +266,7 @@ func TestHandleGetWebSearchConfig(t *testing.T) {
 	if err != nil {
 		t.Fatalf("LoadConfig() error = %v", err)
 	}
+	cfg.Tools.Web.PreferNative = false
 	cfg.Tools.Web.Provider = "sogou"
 	cfg.Tools.Web.Sogou.Enabled = true
 	cfg.Tools.Web.Sogou.MaxResults = 6
@@ -242,6 +303,48 @@ func TestHandleGetWebSearchConfig(t *testing.T) {
 	}
 }
 
+func TestHandleGetWebSearchConfig_DoesNotExposeNativeAsCurrentService(t *testing.T) {
+	configPath, cleanup := setupOAuthTestEnv(t)
+	defer cleanup()
+
+	cfg, err := config.LoadConfig(configPath)
+	if err != nil {
+		t.Fatalf("LoadConfig() error = %v", err)
+	}
+	cfg.Tools.Web.PreferNative = true
+	cfg.Tools.Web.Provider = "brave"
+	cfg.Tools.Web.Sogou.Enabled = false
+	cfg.Tools.Web.DuckDuckGo.Enabled = false
+	cfg.Tools.Web.Brave.Enabled = true
+	cfg.Tools.Web.Brave.SetAPIKeys(nil)
+	if err := config.SaveConfig(configPath, cfg); err != nil {
+		t.Fatalf("SaveConfig() error = %v", err)
+	}
+
+	h := NewHandler(configPath)
+	mux := http.NewServeMux()
+	h.RegisterRoutes(mux)
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/tools/web-search-config", nil)
+	mux.ServeHTTP(rec, req)
+
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status = %d, want %d, body=%s", rec.Code, http.StatusOK, rec.Body.String())
+	}
+
+	var resp webSearchConfigResponse
+	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("Unmarshal() error = %v", err)
+	}
+	if !resp.PreferNative {
+		t.Fatal("prefer_native should remain true in response")
+	}
+	if resp.CurrentService != "" {
+		t.Fatalf("current_service = %q, want empty when no external provider is ready", resp.CurrentService)
+	}
+}
+
 func TestHandleUpdateWebSearchConfig(t *testing.T) {
 	configPath, cleanup := setupOAuthTestEnv(t)
 	defer cleanup()
@@ -393,6 +496,27 @@ func TestResolveCurrentWebSearchProvider_PrefersConfiguredProvidersBeforeSogou(t
 	}
 }
 
+func TestResolveCurrentWebSearchProvider_FallsBackWhenExplicitProviderUnavailable(t *testing.T) {
+	cfg := config.DefaultConfig()
+	cfg.Tools.Web.Provider = "brave"
+	cfg.Tools.Web.Brave.Enabled = true
+	cfg.Tools.Web.Sogou.Enabled = true
+
+	if got := resolveCurrentWebSearchProvider(cfg); got != "sogou" {
+		t.Fatalf("resolveCurrentWebSearchProvider() = %q, want sogou", got)
+	}
+}
+
+func TestResolveCurrentWebSearchProvider_FallsBackWhenProviderIsUnknown(t *testing.T) {
+	cfg := config.DefaultConfig()
+	cfg.Tools.Web.Provider = "totally_unknown"
+	cfg.Tools.Web.Sogou.Enabled = true
+
+	if got := resolveCurrentWebSearchProvider(cfg); got != "sogou" {
+		t.Fatalf("resolveCurrentWebSearchProvider() = %q, want sogou", got)
+	}
+}
+
 func TestResolveCurrentWebSearchProvider_UsesPreferredLanguageForSogouAndDuckDuckGo(t *testing.T) {
 	cfg := config.DefaultConfig()
 	cfg.Tools.Web.Provider = "auto"
@@ -413,3 +537,22 @@ func TestResolveCurrentWebSearchProvider_UsesPreferredLanguageForSogouAndDuckDuc
 		t.Fatalf("resolveCurrentWebSearchProvider() = %q, want sogou", got)
 	}
 }
+
+func TestResolveCurrentWebSearchProvider_IgnoresPreferNativeInConfigView(t *testing.T) {
+	cfg := config.DefaultConfig()
+	cfg.ModelList = []*config.ModelConfig{{
+		ModelName: "custom-default",
+		Model:     "openai/gpt-4o",
+		APIKeys:   config.SimpleSecureStrings("sk-default"),
+	}}
+	cfg.Agents.Defaults.ModelName = "custom-default"
+	cfg.Tools.Web.PreferNative = true
+	cfg.Tools.Web.Provider = "brave"
+	cfg.Tools.Web.Sogou.Enabled = false
+	cfg.Tools.Web.DuckDuckGo.Enabled = false
+	cfg.Tools.Web.Brave.Enabled = true
+
+	if got := resolveCurrentWebSearchProvider(cfg); got != "" {
+		t.Fatalf("resolveCurrentWebSearchProvider() = %q, want empty when only native search would be available", got)
+	}
+}