feat: add userAgent config for ModelConfig

pkg/config/config.go

@@ -598,6 +598,8 @@ type ModelConfig struct {
 	// existing configs, the field is inferred during load: models with API keys
 	// or the reserved "local-model" name are auto-enabled.
 	Enabled bool `json:"enabled,omitempty" yaml:"enabled,omitempty"`
+	// UserAgent is the user agent string to use for HTTP requests.
+	UserAgent string `json:"user_agent,omitempty" yaml:"-"`
 
 	// isVirtual marks this model as a virtual model generated from multi-key expansion.
 	// Virtual models should not be persisted to config files.

pkg/providers/anthropic_messages/provider.go

@@ -41,15 +41,16 @@ type Provider struct {
 	apiKey     string
 	apiBase    string
 	httpClient *http.Client
+	userAgent  string
 }
 
 // NewProvider creates a new Anthropic Messages API provider.
-func NewProvider(apiKey, apiBase string) *Provider {
+func NewProvider(apiKey, apiBase, userAgent string) *Provider {
-	return NewProviderWithTimeout(apiKey, apiBase, 0)
+	return NewProviderWithTimeout(apiKey, apiBase, userAgent, 0)
 }
 
 // NewProviderWithTimeout creates a provider with custom request timeout.
-func NewProviderWithTimeout(apiKey, apiBase string, timeoutSeconds int) *Provider {
+func NewProviderWithTimeout(apiKey, apiBase, userAgent string, timeoutSeconds int) *Provider {
 	baseURL := normalizeBaseURL(apiBase)
 	timeout := defaultRequestTimeout
 	if timeoutSeconds > 0 {
@@ -57,8 +58,9 @@ func NewProviderWithTimeout(apiKey, apiBase string, timeoutSeconds int) *Provide
 	}
 
 	return &Provider{
-		apiKey:  apiKey,
+		apiKey:    apiKey,
-		apiBase: baseURL,
+		apiBase:   baseURL,
+		userAgent: userAgent,
 		httpClient: &http.Client{
 			Timeout: timeout,
 		},
@@ -105,6 +107,9 @@ func (p *Provider) Chat(
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("X-API-Key", p.apiKey) //nolint:canonicalheader // Anthropic API requires exact header name
 	req.Header.Set("Anthropic-Version", defaultAPIVersion)
+	if p.userAgent != "" {
+		req.Header.Set("User-Agent", p.userAgent)
+	}
 
 	// Execute request
 	resp, err := p.httpClient.Do(req)

pkg/providers/anthropic_messages/provider_test.go

@@ -411,7 +411,7 @@ func TestNormalizeBaseURL(t *testing.T) {
 }
 
 func TestNewProvider(t *testing.T) {
-	provider := NewProvider("test-key", "https://api.example.com")
+	provider := NewProvider("test-key", "https://api.example.com", "")
 	if provider == nil {
 		t.Fatal("NewProvider() returned nil")
 	}
@@ -424,7 +424,7 @@ func TestNewProvider(t *testing.T) {
 }
 
 func TestGetDefaultModel(t *testing.T) {
-	provider := NewProvider("test-key", "")
+	provider := NewProvider("test-key", "", "")
 	got := provider.GetDefaultModel()
 	expected := "claude-sonnet-4.6"
 	if got != expected {
@@ -743,7 +743,7 @@ func TestProviderChatErrors(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			// Create provider using constructor to ensure proper initialization
-			provider := NewProvider(tt.apiKey, "https://api.example.com")
+			provider := NewProvider(tt.apiKey, "https://api.example.com", "")
 
 			_, err := provider.Chat(context.Background(), tt.messages, nil, "test-model", nil)
 			if err == nil {

pkg/providers/azure/provider.go

@@ -36,6 +36,7 @@ type Provider struct {
 	apiKey     string
 	apiBase    string
 	httpClient *http.Client
+	userAgent  string
 }
 
 // Option configures the Azure Provider.
@@ -50,11 +51,19 @@ func WithRequestTimeout(timeout time.Duration) Option {
 	}
 }
 
+// WithUserAgent sets the User-Agent header for requests.
+func WithUserAgent(userAgent string) Option {
+	return func(p *Provider) {
+		p.userAgent = userAgent
+	}
+}
+
 // NewProvider creates a new Azure OpenAI provider.
-func NewProvider(apiKey, apiBase, proxy string, opts ...Option) *Provider {
+func NewProvider(apiKey, apiBase, proxy, userAgent string, opts ...Option) *Provider {
 	p := &Provider{
 		apiKey:     apiKey,
 		apiBase:    strings.TrimRight(apiBase, "/"),
+		userAgent:  userAgent,
 		httpClient: common.NewHTTPClient(proxy),
 	}
 
@@ -68,9 +77,9 @@ func NewProvider(apiKey, apiBase, proxy string, opts ...Option) *Provider {
 }
 
 // NewProviderWithTimeout creates a new Azure OpenAI provider with a custom request timeout in seconds.
-func NewProviderWithTimeout(apiKey, apiBase, proxy string, requestTimeoutSeconds int) *Provider {
+func NewProviderWithTimeout(apiKey, apiBase, proxy, userAgent string, requestTimeoutSeconds int) *Provider {
 	return NewProvider(
-		apiKey, apiBase, proxy,
+		apiKey, apiBase, proxy, userAgent,
 		WithRequestTimeout(time.Duration(requestTimeoutSeconds)*time.Second),
 	)
 }
@@ -141,6 +150,9 @@ func (p *Provider) Chat(
 	if p.apiKey != "" {
 		req.Header.Set("Authorization", "Bearer "+p.apiKey)
 	}
+	if p.userAgent != "" {
+		req.Header.Set("User-Agent", p.userAgent)
+	}
 
 	resp, err := p.httpClient.Do(req)
 	if err != nil {

pkg/providers/azure/provider_test.go

@@ -46,7 +46,7 @@ func TestProviderChat_AzureURLConstruction(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "my-gpt5-deployment", nil)
 	if err != nil {
 		t.Fatalf("Chat() error = %v", err)
@@ -69,7 +69,7 @@ func TestProviderChat_AzureAuthHeader(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-azure-key", server.URL, "")
+	p := NewProvider("test-azure-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err != nil {
 		t.Fatalf("Chat() error = %v", err)
@@ -92,7 +92,7 @@ func TestProviderChat_AzureRequestBodyContainsModel(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "my-deployment", nil)
 	if err != nil {
 		t.Fatalf("Chat() error = %v", err)
@@ -112,7 +112,7 @@ func TestProviderChat_AzureUsesMaxOutputTokens(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	_, err := p.Chat(
 		t.Context(),
 		[]Message{{Role: "user", Content: "hi"}},
@@ -144,7 +144,7 @@ func TestProviderChat_AzureStoreIsFalse(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err != nil {
 		t.Fatalf("Chat() error = %v", err)
@@ -161,7 +161,7 @@ func TestProviderChat_AzureHTTPError(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("bad-key", server.URL, "")
+	p := NewProvider("bad-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err == nil {
 		t.Fatal("expected error, got nil")
@@ -176,7 +176,7 @@ func TestProviderChat_AzureRateLimitError(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err == nil {
 		t.Fatal("expected error for 429, got nil")
@@ -194,7 +194,7 @@ func TestProviderChat_AzureServerError(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err == nil {
 		t.Fatal("expected error for 500, got nil")
@@ -229,7 +229,7 @@ func TestProviderChat_AzureParseTextOutput(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	out, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err != nil {
 		t.Fatalf("Chat() error = %v", err)
@@ -270,7 +270,7 @@ func TestProviderChat_AzureParseToolCalls(t *testing.T) {
 	}))
 	defer server.Close()
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 	out, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "weather?"}}, nil, "deployment", nil)
 	if err != nil {
 		t.Fatalf("Chat() error = %v", err)
@@ -287,7 +287,7 @@ func TestProviderChat_AzureParseToolCalls(t *testing.T) {
 }
 
 func TestProvider_AzureEmptyAPIBase(t *testing.T) {
-	p := NewProvider("test-key", "", "")
+	p := NewProvider("test-key", "", "", "")
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "deployment", nil)
 	if err == nil {
 		t.Fatal("expected error for empty API base")
@@ -295,21 +295,21 @@ func TestProvider_AzureEmptyAPIBase(t *testing.T) {
 }
 
 func TestProvider_AzureRequestTimeoutDefault(t *testing.T) {
-	p := NewProvider("test-key", "https://example.com", "")
+	p := NewProvider("test-key", "https://example.com", "", "")
 	if p.httpClient.Timeout != defaultRequestTimeout {
 		t.Errorf("timeout = %v, want %v", p.httpClient.Timeout, defaultRequestTimeout)
 	}
 }
 
 func TestProvider_AzureRequestTimeoutOverride(t *testing.T) {
-	p := NewProvider("test-key", "https://example.com", "", WithRequestTimeout(300*time.Second))
+	p := NewProvider("test-key", "https://example.com", "", "", WithRequestTimeout(300*time.Second))
 	if p.httpClient.Timeout != 300*time.Second {
 		t.Errorf("timeout = %v, want %v", p.httpClient.Timeout, 300*time.Second)
 	}
 }
 
 func TestProvider_AzureNewProviderWithTimeout(t *testing.T) {
-	p := NewProviderWithTimeout("test-key", "https://example.com", "", 180)
+	p := NewProviderWithTimeout("test-key", "https://example.com", "", "", 180)
 	if p.httpClient.Timeout != 180*time.Second {
 		t.Errorf("timeout = %v, want %v", p.httpClient.Timeout, 180*time.Second)
 	}
@@ -343,7 +343,7 @@ func TestProviderChat_AzureNativeWebSearchInjection(t *testing.T) {
 		},
 	}
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 
 	// With native_search=true: user-defined web_search should be replaced by built-in
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, tools, "deployment",
@@ -393,7 +393,7 @@ func TestProviderChat_AzureNoNativeWebSearch(t *testing.T) {
 		},
 	}
 
-	p := NewProvider("test-key", server.URL, "")
+	p := NewProvider("test-key", server.URL, "", "")
 
 	// Without native_search: user-defined web_search should be kept as-is
 	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, tools, "deployment", nil)

pkg/providers/factory_provider.go

@@ -138,6 +138,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 			apiBase,
 			cfg.Proxy,
 			cfg.MaxTokensField,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 			cfg.ExtraBody,
 		), modelID, nil
@@ -157,6 +158,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 			cfg.APIKey(),
 			cfg.APIBase,
 			cfg.Proxy,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 		), modelID, nil
 
@@ -214,6 +216,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 			apiBase,
 			cfg.Proxy,
 			cfg.MaxTokensField,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 			cfg.ExtraBody,
 		), modelID, nil
@@ -239,6 +242,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 			apiBase,
 			cfg.Proxy,
 			cfg.MaxTokensField,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 			extraBody,
 		), modelID, nil
@@ -265,6 +269,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 			apiBase,
 			cfg.Proxy,
 			cfg.MaxTokensField,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 			cfg.ExtraBody,
 		), modelID, nil
@@ -281,6 +286,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 		return anthropicmessages.NewProviderWithTimeout(
 			cfg.APIKey(),
 			apiBase,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 		), modelID, nil
 
@@ -296,6 +302,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 		return anthropicmessages.NewProviderWithTimeout(
 			cfg.APIKey(),
 			apiBase,
+			cfg.UserAgent,
 			cfg.RequestTimeout,
 		), modelID, nil
 

pkg/providers/http_provider.go

@@ -24,11 +24,11 @@ func NewHTTPProvider(apiKey, apiBase, proxy string) *HTTPProvider {
 }
 
 func NewHTTPProviderWithMaxTokensField(apiKey, apiBase, proxy, maxTokensField string) *HTTPProvider {
-	return NewHTTPProviderWithMaxTokensFieldAndRequestTimeout(apiKey, apiBase, proxy, maxTokensField, 0, nil)
+	return NewHTTPProviderWithMaxTokensFieldAndRequestTimeout(apiKey, apiBase, proxy, maxTokensField, "", 0, nil)
 }
 
 func NewHTTPProviderWithMaxTokensFieldAndRequestTimeout(
-	apiKey, apiBase, proxy, maxTokensField string,
+	apiKey, apiBase, proxy, maxTokensField, userAgent string,
 	requestTimeoutSeconds int,
 	extraBody map[string]any,
 ) *HTTPProvider {
@@ -40,6 +40,7 @@ func NewHTTPProviderWithMaxTokensFieldAndRequestTimeout(
 			openai_compat.WithMaxTokensField(maxTokensField),
 			openai_compat.WithRequestTimeout(time.Duration(requestTimeoutSeconds)*time.Second),
 			openai_compat.WithExtraBody(extraBody),
+			openai_compat.WithUserAgent(userAgent),
 		),
 	}
 }

pkg/providers/openai_compat/provider.go

@@ -36,6 +36,7 @@ type Provider struct {
 	maxTokensField string // Field name for max tokens (e.g., "max_completion_tokens" for o1/glm models)
 	httpClient     *http.Client
 	extraBody      map[string]any // Additional fields to inject into request body
+	userAgent      string
 }
 
 type Option func(*Provider)
@@ -65,6 +66,12 @@ func WithMaxTokensField(maxTokensField string) Option {
 	}
 }
 
+func WithUserAgent(userAgent string) Option {
+	return func(p *Provider) {
+		p.userAgent = userAgent
+	}
+}
+
 func WithRequestTimeout(timeout time.Duration) Option {
 	return func(p *Provider) {
 		if timeout > 0 {
@@ -197,6 +204,9 @@ func (p *Provider) Chat(
 	}
 
 	req.Header.Set("Content-Type", "application/json")
+	if p.userAgent != "" {
+		req.Header.Set("User-Agent", p.userAgent)
+	}
 	if p.apiKey != "" {
 		req.Header.Set("Authorization", "Bearer "+p.apiKey)
 	}