fix: add default copilot claude model aliases for oauth routing

internal/config/config.go

@@ -759,22 +759,24 @@ func (cfg *Config) SanitizeOAuthModelAlias() {
 		return
 	}
 
-	// Inject default Kiro aliases if no user-configured kiro aliases exist
+	// Inject channel defaults when the channel is absent in user config.
+	// Presence is checked case-insensitively and includes explicit nil/empty markers.
 	if cfg.OAuthModelAlias == nil {
 		cfg.OAuthModelAlias = make(map[string][]OAuthModelAlias)
 	}
-	if _, hasKiro := cfg.OAuthModelAlias["kiro"]; !hasKiro {
-		// Check case-insensitive too
-		found := false
+	hasChannel := func(channel string) bool {
 		for k := range cfg.OAuthModelAlias {
-			if strings.EqualFold(strings.TrimSpace(k), "kiro") {
-				found = true
-				break
+			if strings.EqualFold(strings.TrimSpace(k), channel) {
+				return true
 			}
 		}
-		if !found {
-			cfg.OAuthModelAlias["kiro"] = defaultKiroAliases()
-		}
+		return false
+	}
+	if !hasChannel("kiro") {
+		cfg.OAuthModelAlias["kiro"] = defaultKiroAliases()
+	}
+	if !hasChannel("github-copilot") {
+		cfg.OAuthModelAlias["github-copilot"] = defaultGitHubCopilotAliases()
 	}
 
 	if len(cfg.OAuthModelAlias) == 0 {

internal/config/oauth_model_alias_migration.go

@@ -42,6 +42,21 @@ func defaultKiroAliases() []OAuthModelAlias {
 	}
 }
 
+// defaultGitHubCopilotAliases returns default oauth-model-alias entries that
+// expose Claude hyphen-style IDs for GitHub Copilot Claude models.
+// This keeps compatibility with clients (e.g. Claude Code) that use
+// Anthropic-style model IDs like "claude-opus-4-6".
+func defaultGitHubCopilotAliases() []OAuthModelAlias {
+	return []OAuthModelAlias{
+		{Name: "claude-haiku-4.5", Alias: "claude-haiku-4-5", Fork: true},
+		{Name: "claude-opus-4.1", Alias: "claude-opus-4-1", Fork: true},
+		{Name: "claude-opus-4.5", Alias: "claude-opus-4-5", Fork: true},
+		{Name: "claude-opus-4.6", Alias: "claude-opus-4-6", Fork: true},
+		{Name: "claude-sonnet-4.5", Alias: "claude-sonnet-4-5", Fork: true},
+		{Name: "claude-sonnet-4.6", Alias: "claude-sonnet-4-6", Fork: true},
+	}
+}
+
 // defaultAntigravityAliases returns the default oauth-model-alias configuration
 // for the antigravity channel when neither field exists.
 func defaultAntigravityAliases() []OAuthModelAlias {

internal/config/oauth_model_alias_test.go

@@ -107,6 +107,44 @@ func TestSanitizeOAuthModelAlias_InjectsDefaultKiroAliases(t *testing.T) {
 	}
 }
 
+func TestSanitizeOAuthModelAlias_InjectsDefaultGitHubCopilotAliases(t *testing.T) {
+	cfg := &Config{
+		OAuthModelAlias: map[string][]OAuthModelAlias{
+			"codex": {
+				{Name: "gpt-5", Alias: "g5"},
+			},
+		},
+	}
+
+	cfg.SanitizeOAuthModelAlias()
+
+	copilotAliases := cfg.OAuthModelAlias["github-copilot"]
+	if len(copilotAliases) == 0 {
+		t.Fatal("expected default github-copilot aliases to be injected")
+	}
+
+	aliasSet := make(map[string]bool, len(copilotAliases))
+	for _, a := range copilotAliases {
+		aliasSet[a.Alias] = true
+		if !a.Fork {
+			t.Fatalf("expected all default github-copilot aliases to have fork=true, got fork=false for %q", a.Alias)
+		}
+	}
+	expectedAliases := []string{
+		"claude-haiku-4-5",
+		"claude-opus-4-1",
+		"claude-opus-4-5",
+		"claude-opus-4-6",
+		"claude-sonnet-4-5",
+		"claude-sonnet-4-6",
+	}
+	for _, expected := range expectedAliases {
+		if !aliasSet[expected] {
+			t.Fatalf("expected default github-copilot alias %q to be present", expected)
+		}
+	}
+}
+
 func TestSanitizeOAuthModelAlias_DoesNotOverrideUserKiroAliases(t *testing.T) {
 	// When user has configured kiro aliases, defaults should NOT be injected
 	cfg := &Config{
@@ -128,6 +166,26 @@ func TestSanitizeOAuthModelAlias_DoesNotOverrideUserKiroAliases(t *testing.T) {
 	}
 }
 
+func TestSanitizeOAuthModelAlias_DoesNotOverrideUserGitHubCopilotAliases(t *testing.T) {
+	cfg := &Config{
+		OAuthModelAlias: map[string][]OAuthModelAlias{
+			"github-copilot": {
+				{Name: "claude-opus-4.6", Alias: "my-opus", Fork: true},
+			},
+		},
+	}
+
+	cfg.SanitizeOAuthModelAlias()
+
+	copilotAliases := cfg.OAuthModelAlias["github-copilot"]
+	if len(copilotAliases) != 1 {
+		t.Fatalf("expected 1 user-configured github-copilot alias, got %d", len(copilotAliases))
+	}
+	if copilotAliases[0].Alias != "my-opus" {
+		t.Fatalf("expected user alias to be preserved, got %q", copilotAliases[0].Alias)
+	}
+}
+
 func TestSanitizeOAuthModelAlias_DoesNotReinjectAfterExplicitDeletion(t *testing.T) {
 	// When user explicitly deletes kiro aliases (key exists with nil value),
 	// defaults should NOT be re-injected on subsequent sanitize calls (#222).
@@ -154,6 +212,24 @@ func TestSanitizeOAuthModelAlias_DoesNotReinjectAfterExplicitDeletion(t *testing
 	}
 }
 
+func TestSanitizeOAuthModelAlias_GitHubCopilotDoesNotReinjectAfterExplicitDeletion(t *testing.T) {
+	cfg := &Config{
+		OAuthModelAlias: map[string][]OAuthModelAlias{
+			"github-copilot": nil, // explicitly deleted
+		},
+	}
+
+	cfg.SanitizeOAuthModelAlias()
+
+	copilotAliases := cfg.OAuthModelAlias["github-copilot"]
+	if len(copilotAliases) != 0 {
+		t.Fatalf("expected github-copilot aliases to remain empty after explicit deletion, got %d aliases", len(copilotAliases))
+	}
+	if _, exists := cfg.OAuthModelAlias["github-copilot"]; !exists {
+		t.Fatal("expected github-copilot key to be preserved as nil marker after sanitization")
+	}
+}
+
 func TestSanitizeOAuthModelAlias_DoesNotReinjectAfterExplicitDeletionEmpty(t *testing.T) {
 	// Same as above but with empty slice instead of nil (PUT with empty body).
 	cfg := &Config{