fix: stabilize claude device fingerprint

internal/config/claude_header_defaults_test.go

@@ -0,0 +1,48 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestLoadConfigOptional_ClaudeHeaderDefaults(t *testing.T) {
+	dir := t.TempDir()
+	configPath := filepath.Join(dir, "config.yaml")
+	configYAML := []byte(`
+claude-header-defaults:
+  user-agent: "  claude-cli/2.1.70 (external, cli)  "
+  package-version: "  0.80.0  "
+  runtime-version: "  v24.5.0  "
+  os: "  MacOS  "
+  arch: "  arm64  "
+  timeout: "  900  "
+`)
+	if err := os.WriteFile(configPath, configYAML, 0o600); err != nil {
+		t.Fatalf("failed to write config: %v", err)
+	}
+
+	cfg, err := LoadConfigOptional(configPath, false)
+	if err != nil {
+		t.Fatalf("LoadConfigOptional() error = %v", err)
+	}
+
+	if got := cfg.ClaudeHeaderDefaults.UserAgent; got != "claude-cli/2.1.70 (external, cli)" {
+		t.Fatalf("UserAgent = %q, want %q", got, "claude-cli/2.1.70 (external, cli)")
+	}
+	if got := cfg.ClaudeHeaderDefaults.PackageVersion; got != "0.80.0" {
+		t.Fatalf("PackageVersion = %q, want %q", got, "0.80.0")
+	}
+	if got := cfg.ClaudeHeaderDefaults.RuntimeVersion; got != "v24.5.0" {
+		t.Fatalf("RuntimeVersion = %q, want %q", got, "v24.5.0")
+	}
+	if got := cfg.ClaudeHeaderDefaults.OS; got != "MacOS" {
+		t.Fatalf("OS = %q, want %q", got, "MacOS")
+	}
+	if got := cfg.ClaudeHeaderDefaults.Arch; got != "arm64" {
+		t.Fatalf("Arch = %q, want %q", got, "arm64")
+	}
+	if got := cfg.ClaudeHeaderDefaults.Timeout; got != "900" {
+		t.Fatalf("Timeout = %q, want %q", got, "900")
+	}
+}

internal/config/config.go

@@ -134,6 +134,8 @@ type ClaudeHeaderDefaults struct {
 	UserAgent      string `yaml:"user-agent" json:"user-agent"`
 	PackageVersion string `yaml:"package-version" json:"package-version"`
 	RuntimeVersion string `yaml:"runtime-version" json:"runtime-version"`
+	OS             string `yaml:"os" json:"os"`
+	Arch           string `yaml:"arch" json:"arch"`
 	Timeout        string `yaml:"timeout" json:"timeout"`
 }
 
@@ -630,6 +632,9 @@ func LoadConfigOptional(configFile string, optional bool) (*Config, error) {
 	// Sanitize Codex header defaults.
 	cfg.SanitizeCodexHeaderDefaults()
 
+	// Sanitize Claude header defaults.
+	cfg.SanitizeClaudeHeaderDefaults()
+
 	// Sanitize Claude key headers
 	cfg.SanitizeClaudeKeys()
 
@@ -729,6 +734,20 @@ func (cfg *Config) SanitizeCodexHeaderDefaults() {
 	cfg.CodexHeaderDefaults.BetaFeatures = strings.TrimSpace(cfg.CodexHeaderDefaults.BetaFeatures)
 }
 
+// SanitizeClaudeHeaderDefaults trims surrounding whitespace from the
+// configured Claude fingerprint baseline values.
+func (cfg *Config) SanitizeClaudeHeaderDefaults() {
+	if cfg == nil {
+		return
+	}
+	cfg.ClaudeHeaderDefaults.UserAgent = strings.TrimSpace(cfg.ClaudeHeaderDefaults.UserAgent)
+	cfg.ClaudeHeaderDefaults.PackageVersion = strings.TrimSpace(cfg.ClaudeHeaderDefaults.PackageVersion)
+	cfg.ClaudeHeaderDefaults.RuntimeVersion = strings.TrimSpace(cfg.ClaudeHeaderDefaults.RuntimeVersion)
+	cfg.ClaudeHeaderDefaults.OS = strings.TrimSpace(cfg.ClaudeHeaderDefaults.OS)
+	cfg.ClaudeHeaderDefaults.Arch = strings.TrimSpace(cfg.ClaudeHeaderDefaults.Arch)
+	cfg.ClaudeHeaderDefaults.Timeout = strings.TrimSpace(cfg.ClaudeHeaderDefaults.Timeout)
+}
+
 // SanitizeOAuthModelAlias normalizes and deduplicates global OAuth model name aliases.
 // It trims whitespace, normalizes channel keys to lower-case, drops empty entries,
 // allows multiple aliases per upstream name, and ensures aliases are unique within each channel.