feat(auth): add Anthropic OAuth setup-token login flow

Add support for Anthropic's OAuth-based setup tokens (sk-ant-oat01-*)
as an alternative to API keys. This includes:

- New `--setup-token` flag on `auth login` command
- Interactive login menu for Anthropic (setup token vs API key)
- Setup token validation and credential storage with oauth auth method
- Usage endpoint integration to show 5h/7d utilization in `auth status`
- Streaming support for OAuth tokens (required by Anthropic API)
- Model ID normalization (dots to hyphens) for API compatibility
- Remove .env.example (secrets should not be templated)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -1,20 +0,0 @@
-# ── LLM Provider ──────────────────────────
-# Uncomment and set the API key for your provider
-# OPENROUTER_API_KEY=sk-or-v1-xxx
-# ZHIPU_API_KEY=xxx
-# ANTHROPIC_API_KEY=sk-ant-xxx
-# OPENAI_API_KEY=sk-xxx
-# GEMINI_API_KEY=xxx
-# CEREBRAS_API_KEY=xxx
-
-# ── Chat Channel ──────────────────────────
-# TELEGRAM_BOT_TOKEN=123456:ABC...
-# DISCORD_BOT_TOKEN=xxx
-# LINE_CHANNEL_SECRET=xxx
-# LINE_CHANNEL_ACCESS_TOKEN=xxx
-
-# ── Web Search (optional) ────────────────
-# BRAVE_SEARCH_API_KEY=BSA...
-
-# ── Timezone ──────────────────────────────
-TZ=Asia/Tokyo

cmd/picoclaw/internal/auth/helpers.go

@@ -1,6 +1,7 @@
 package auth
 
 import (
+	"bufio"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -17,12 +18,12 @@ import (
 
 const supportedProvidersMsg = "supported providers: openai, anthropic, google-antigravity"
 
-func authLoginCmd(provider string, useDeviceCode bool) error {
+func authLoginCmd(provider string, useDeviceCode bool, setupToken bool) error {
 	switch provider {
 	case "openai":
 		return authLoginOpenAI(useDeviceCode)
 	case "anthropic":
-		return authLoginPasteToken(provider)
+		return authLoginAnthropic(setupToken)
 	case "google-antigravity", "antigravity":
 		return authLoginGoogleAntigravity()
 	default:
@@ -163,6 +164,78 @@ func authLoginGoogleAntigravity() error {
 	return nil
 }
 
+func authLoginAnthropic(setupToken bool) error {
+	if setupToken {
+		return authLoginAnthropicSetupToken()
+	}
+
+	fmt.Println("Anthropic login method:")
+	fmt.Println("  1) Setup token (from `claude setup-token`) (Recommended)")
+	fmt.Println("  2) API key (from console.anthropic.com)")
+	fmt.Print("Choose [1]: ")
+
+	scanner := bufio.NewScanner(os.Stdin)
+	choice := "1"
+	if scanner.Scan() {
+		text := strings.TrimSpace(scanner.Text())
+		if text != "" {
+			choice = text
+		}
+	}
+
+	switch choice {
+	case "1":
+		return authLoginAnthropicSetupToken()
+	case "2":
+		return authLoginPasteToken("anthropic")
+	default:
+		return fmt.Errorf("invalid choice: %s", choice)
+	}
+}
+
+func authLoginAnthropicSetupToken() error {
+	cred, err := auth.LoginSetupToken(os.Stdin)
+	if err != nil {
+		return fmt.Errorf("login failed: %w", err)
+	}
+
+	if err = auth.SetCredential("anthropic", cred); err != nil {
+		return fmt.Errorf("failed to save credentials: %w", err)
+	}
+
+	appCfg, err := internal.LoadConfig()
+	if err == nil {
+		appCfg.Providers.Anthropic.AuthMethod = "oauth"
+
+		found := false
+		for i := range appCfg.ModelList {
+			if isAnthropicModel(appCfg.ModelList[i].Model) {
+				appCfg.ModelList[i].AuthMethod = "oauth"
+				found = true
+				break
+			}
+		}
+		if !found {
+			appCfg.ModelList = append(appCfg.ModelList, config.ModelConfig{
+				ModelName:  "claude-sonnet-4.6",
+				Model:      "anthropic/claude-sonnet-4.6",
+				AuthMethod: "oauth",
+			})
+		}
+
+		appCfg.Agents.Defaults.ModelName = "claude-sonnet-4.6"
+
+		if err := config.SaveConfig(internal.GetConfigPath(), appCfg); err != nil {
+			return fmt.Errorf("could not update config: %w", err)
+		}
+	}
+
+	fmt.Println("Setup token saved for Anthropic!")
+	fmt.Println("Default model set to: claude-sonnet-4.6")
+
+	return nil
+}
+
 func fetchGoogleUserEmail(accessToken string) (string, error) {
 	req, err := http.NewRequest("GET", "https://www.googleapis.com/oauth2/v2/userinfo", nil)
 	if err != nil {
@@ -360,6 +433,16 @@ func authStatusCmd() error {
 		if !cred.ExpiresAt.IsZero() {
 			fmt.Printf("    Expires: %s\n", cred.ExpiresAt.Format("2006-01-02 15:04"))
 		}
+
+		if provider == "anthropic" && cred.AuthMethod == "oauth" {
+			usage, err := auth.FetchAnthropicUsage(cred.AccessToken)
+			if err != nil {
+				fmt.Printf("    Usage: unavailable (%v)\n", err)
+			} else {
+				fmt.Printf("    Usage (5h):  %.1f%%\n", usage.FiveHourUtilization*100)
+				fmt.Printf("    Usage (7d):  %.1f%%\n", usage.SevenDayUtilization*100)
+			}
+		}
 	}
 
 	return nil

cmd/picoclaw/internal/auth/login.go

@@ -6,6 +6,7 @@ func newLoginCommand() *cobra.Command {
 	var (
 		provider      string
 		useDeviceCode bool
+		setupToken    bool
 	)
 
 	cmd := &cobra.Command{
@@ -13,12 +14,13 @@ func newLoginCommand() *cobra.Command {
 		Short: "Login via OAuth or paste token",
 		Args:  cobra.NoArgs,
 		RunE: func(cmd *cobra.Command, _ []string) error {
-			return authLoginCmd(provider, useDeviceCode)
+			return authLoginCmd(provider, useDeviceCode, setupToken)
 		},
 	}
 
 	cmd.Flags().StringVarP(&provider, "provider", "p", "", "Provider to login with (openai, anthropic)")
 	cmd.Flags().BoolVar(&useDeviceCode, "device-code", false, "Use device code flow (for headless environments)")
+	cmd.Flags().BoolVar(&setupToken, "setup-token", false, "Use setup-token flow for Anthropic (from `claude setup-token`)")
 	_ = cmd.MarkFlagRequired("provider")
 
 	return cmd

pkg/auth/token.go

@@ -31,6 +31,38 @@ func LoginPasteToken(provider string, r io.Reader) (*AuthCredential, error) {
 	}, nil
 }
 
+func LoginSetupToken(r io.Reader) (*AuthCredential, error) {
+	fmt.Println("Paste your setup token from `claude setup-token`:")
+	fmt.Print("> ")
+
+	scanner := bufio.NewScanner(r)
+	if !scanner.Scan() {
+		if err := scanner.Err(); err != nil {
+			return nil, fmt.Errorf("reading token: %w", err)
+		}
+		return nil, fmt.Errorf("no input received")
+	}
+
+	token := strings.TrimSpace(scanner.Text())
+	if token == "" {
+		return nil, fmt.Errorf("token cannot be empty")
+	}
+
+	if !strings.HasPrefix(token, "sk-ant-oat01-") {
+		return nil, fmt.Errorf("invalid setup token: expected prefix sk-ant-oat01-")
+	}
+
+	if len(token) < 80 {
+		return nil, fmt.Errorf("invalid setup token: too short (expected at least 80 characters)")
+	}
+
+	return &AuthCredential{
+		AccessToken: token,
+		Provider:    "anthropic",
+		AuthMethod:  "oauth",
+	}, nil
+}
+
 func providerDisplayName(provider string) string {
 	switch provider {
 	case "anthropic":

pkg/auth/usage.go

@@ -0,0 +1,58 @@
+package auth
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+type AnthropicUsage struct {
+	FiveHourUtilization float64
+	SevenDayUtilization float64
+}
+
+func FetchAnthropicUsage(token string) (*AnthropicUsage, error) {
+	req, err := http.NewRequest("GET", "https://api.anthropic.com/api/oauth/usage", nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("anthropic-version", "2023-06-01")
+	req.Header.Set("anthropic-beta", "oauth-2025-04-20")
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, _ := io.ReadAll(resp.Body)
+
+	if resp.StatusCode == http.StatusForbidden {
+		return nil, fmt.Errorf("insufficient scope: usage endpoint requires oauth scope")
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("usage request failed (%d): %s", resp.StatusCode, string(body))
+	}
+
+	var result struct {
+		FiveHour struct {
+			Utilization float64 `json:"utilization"`
+		} `json:"five_hour"`
+		SevenDay struct {
+			Utilization float64 `json:"utilization"`
+		} `json:"seven_day"`
+	}
+	if err := json.Unmarshal(body, &result); err != nil {
+		return nil, fmt.Errorf("parsing usage response: %w", err)
+	}
+
+	return &AnthropicUsage{
+		FiveHourUtilization: result.FiveHour.Utilization,
+		SevenDayUtilization: result.SevenDay.Utilization,
+	}, nil
+}

pkg/providers/anthropic/provider.go

@@ -77,7 +77,10 @@ func (p *Provider) Chat(
 		if err != nil {
 			return nil, fmt.Errorf("refreshing token: %w", err)
 		}
-		opts = append(opts, option.WithAuthToken(tok))
+		opts = append(opts,
+			option.WithAuthToken(tok),
+			option.WithHeader("anthropic-beta", "oauth-2025-04-20"),
+		)
 	}
 
 	params, err := buildParams(messages, tools, model, options)
@@ -85,6 +88,11 @@ func (p *Provider) Chat(
 		return nil, err
 	}
 
+	// OAuth/setup-tokens require streaming; API keys use non-streaming.
+	if p.tokenSource != nil {
+		return p.chatStreaming(ctx, params, opts)
+	}
+
 	resp, err := p.client.Messages.New(ctx, params, opts...)
 	if err != nil {
 		return nil, fmt.Errorf("claude API call: %w", err)
@@ -93,6 +101,28 @@ func (p *Provider) Chat(
 	return parseResponse(resp), nil
 }
 
+func (p *Provider) chatStreaming(
+	ctx context.Context,
+	params anthropic.MessageNewParams,
+	opts []option.RequestOption,
+) (*LLMResponse, error) {
+	stream := p.client.Messages.NewStreaming(ctx, params, opts...)
+	defer stream.Close()
+
+	var msg anthropic.Message
+	for stream.Next() {
+		event := stream.Current()
+		if err := msg.Accumulate(event); err != nil {
+			return nil, fmt.Errorf("claude streaming accumulate: %w", err)
+		}
+	}
+	if err := stream.Err(); err != nil {
+		return nil, fmt.Errorf("claude API call: %w", err)
+	}
+
+	return parseResponse(&msg), nil
+}
+
 func (p *Provider) GetDefaultModel() string {
 	return "claude-sonnet-4.6"
 }
@@ -164,8 +194,12 @@ func buildParams(
 		maxTokens = int64(mt)
 	}
 
+	// Normalize model ID: Anthropic API uses hyphens (claude-sonnet-4-6),
+	// but config may use dots (claude-sonnet-4.6).
+	apiModel := strings.ReplaceAll(model, ".", "-")
+
 	params := anthropic.MessageNewParams{
-		Model:     anthropic.Model(model),
+		Model:     anthropic.Model(apiModel),
 		Messages:  anthropicMessages,
 		MaxTokens: maxTokens,
 	}

pkg/providers/anthropic/provider_test.go

@@ -21,8 +21,8 @@ func TestBuildParams_BasicMessage(t *testing.T) {
 	if err != nil {
 		t.Fatalf("buildParams() error: %v", err)
 	}
-	if string(params.Model) != "claude-sonnet-4.6" {
-		t.Errorf("Model = %q, want %q", params.Model, "claude-sonnet-4.6")
+	if string(params.Model) != "claude-sonnet-4-6" {
+		t.Errorf("Model = %q, want %q", params.Model, "claude-sonnet-4-6")
 	}
 	if params.MaxTokens != 1024 {
 		t.Errorf("MaxTokens = %d, want 1024", params.MaxTokens)