diff --git a/cmd/auth/auth_test.go b/cmd/auth/auth_test.go
index f633a61433..289b9e70a1 100644
--- a/cmd/auth/auth_test.go
+++ b/cmd/auth/auth_test.go
@@ -386,7 +386,7 @@ func TestAuthScopesRun_UsesTenantAccessTokenFromCredentialProvider(t *testing.T)
 		AppID: "test-app", AppSecret: "", Brand: core.BrandFeishu,
 	})
 	tokenResolver := &authScopesTokenResolver{}
-	f.Credential = credential.NewCredentialProvider(nil, nil, tokenResolver, nil)
+	f.Credential = newAuthTestCredentialProvider("test-app", tokenResolver)
 
 	appInfoStub := &httpmock.Stub{
 		Method: http.MethodGet,
@@ -442,7 +442,7 @@ func TestAuthScopesRun_LarkPermissionError_TypedAsPermissionError(t *testing.T)
 		AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu,
 	})
 	tokenResolver := &authScopesTokenResolver{}
-	f.Credential = credential.NewCredentialProvider(nil, nil, tokenResolver, nil)
+	f.Credential = newAuthTestCredentialProvider("test-app", tokenResolver)
 
 	reg.Register(&httpmock.Stub{
 		Method: http.MethodGet,
@@ -485,6 +485,18 @@ type authScopesTokenResolver struct {
 	requests []credential.TokenSpec
 }
 
+type authTestAccountResolver struct {
+	appID string
+}
+
+func (r authTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID, Brand: core.BrandFeishu}, nil
+}
+
+func newAuthTestCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, authTestAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 func (r *authScopesTokenResolver) ResolveToken(ctx context.Context, req credential.TokenSpec) (*credential.TokenResult, error) {
 	r.requests = append(r.requests, req)
 	switch req.Type {
diff --git a/cmd/auth/status.go b/cmd/auth/status.go
index 15de7dda9c..b8b4492926 100644
--- a/cmd/auth/status.go
+++ b/cmd/auth/status.go
@@ -27,6 +27,9 @@ func NewCmdAuthStatus(f *cmdutil.Factory, runF func(*StatusOptions) error) *cobr
 	cmd := &cobra.Command{
 		Use:   "status",
 		Short: "View current auth status",
+		Long: `Show OAuth user login, token validity, and granted scopes.
+For token-validity checks, run lark-cli auth status --json --verify.
+This is not profile/app selection diagnostics; use lark-cli whoami for the effective app/profile identity used by an invocation.`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if runF != nil {
 				return runF(opts)
diff --git a/cmd/auth/status_test.go b/cmd/auth/status_test.go
index 7bf0608c77..895dba238d 100644
--- a/cmd/auth/status_test.go
+++ b/cmd/auth/status_test.go
@@ -4,15 +4,35 @@
 package auth
 
 import (
+	"context"
 	"encoding/json"
 	"net/http"
+	"strings"
 	"testing"
 
+	extcred "github.com/larksuite/cli/extension/credential"
+	envprovider "github.com/larksuite/cli/extension/credential/env"
 	"github.com/larksuite/cli/internal/cmdutil"
 	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/credential"
+	"github.com/larksuite/cli/internal/envvars"
 	"github.com/larksuite/cli/internal/httpmock"
 )
 
+func TestAuthStatusHelpDistinguishesFromWhoami(t *testing.T) {
+	cmd := NewCmdAuthStatus(nil, nil)
+	for _, want := range []string{
+		"OAuth user login",
+		"auth status --json --verify",
+		"not profile/app selection diagnostics",
+		"lark-cli whoami",
+	} {
+		if !strings.Contains(cmd.Long, want) {
+			t.Errorf("auth status --help Long missing %q; got:\n%s", want, cmd.Long)
+		}
+	}
+}
+
 func TestAuthStatusRun_SplitsBotAndUserIdentity(t *testing.T) {
 	f, stdout, _, _ := cmdutil.TestFactory(t, &core.CliConfig{
 		AppID: "test-app", AppSecret: "secret", Brand: core.BrandFeishu,
@@ -79,6 +99,51 @@ func TestAuthStatusRun_VerifyReportsBotIdentity(t *testing.T) {
 	}
 }
 
+type fixedStatusAccountResolver struct {
+	account *credential.Account
+}
+
+func (r *fixedStatusAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return r.account, nil
+}
+
+func TestAuthStatus_AllowsMatchingAppIDOnlySelectedProfile(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	t.Setenv(envvars.CliAppID, "cli_a")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	if err := core.SaveMultiAppConfig(&core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{{
+			Name:      "tenant_a",
+			AppId:     "cli_a",
+			AppSecret: core.PlainSecret("test-secret"),
+			Brand:     core.BrandFeishu,
+		}},
+	}); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	config := &core.CliConfig{ProfileName: "tenant_a", AppID: "cli_a", AppSecret: "test-secret", Brand: core.BrandFeishu}
+	f, stdout, _, _ := cmdutil.TestFactory(t, config)
+	f.Credential = credential.NewCredentialProvider(
+		[]extcred.Provider{&envprovider.Provider{}},
+		&fixedStatusAccountResolver{account: credential.AccountFromCliConfig(config)},
+		nil,
+		nil,
+	).WithProfileFromFlag("tenant_a")
+
+	cmd := NewCmdAuth(f)
+	cmd.SetArgs([]string{"status", "--json"})
+	if err := cmd.Execute(); err != nil {
+		t.Fatalf("auth status should use the selected built-in profile: %v", err)
+	}
+	if strings.Contains(stdout.String(), "credentials are provided externally") {
+		t.Fatalf("matching APP_ID-only env was misclassified as external:\n%s", stdout.String())
+	}
+}
+
 type statusOutput struct {
 	Identity   string `json:"identity"`
 	Verified   *bool  `json:"verified"`
diff --git a/cmd/bootstrap.go b/cmd/bootstrap.go
index 841a884094..c5f6c667d8 100644
--- a/cmd/bootstrap.go
+++ b/cmd/bootstrap.go
@@ -6,8 +6,10 @@ package cmd
 import (
 	"errors"
 	"io"
+	"os"
 
 	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/envvars"
 	"github.com/spf13/pflag"
 )
 
@@ -26,5 +28,13 @@ func BootstrapInvocationContext(args []string) (cmdutil.InvocationContext, error
 	if err := fs.Parse(args); err != nil && !errors.Is(err, pflag.ErrHelp) {
 		return cmdutil.InvocationContext{}, err
 	}
-	return cmdutil.InvocationContext{Profile: globals.Profile}, nil
+
+	profileFromFlag := fs.Changed("profile")
+	if !profileFromFlag {
+		globals.Profile = os.Getenv(envvars.CliProfile)
+	}
+	return cmdutil.InvocationContext{
+		Profile:         globals.Profile,
+		ProfileFromFlag: profileFromFlag,
+	}, nil
 }
diff --git a/cmd/bootstrap_test.go b/cmd/bootstrap_test.go
index aa5fd3de79..2ea162d995 100644
--- a/cmd/bootstrap_test.go
+++ b/cmd/bootstrap_test.go
@@ -3,7 +3,11 @@
 
 package cmd
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/larksuite/cli/internal/envvars"
+)
 
 func TestBootstrapInvocationContext_ProfileFlag(t *testing.T) {
 	inv, err := BootstrapInvocationContext([]string{"--profile", "target", "auth", "status"})
@@ -70,3 +74,58 @@ func TestBootstrapInvocationContext_HelpWithProfile(t *testing.T) {
 		t.Fatalf("profile = %q, want %q", inv.Profile, "target")
 	}
 }
+
+func TestBootstrapProfileEnvFallback(t *testing.T) {
+	t.Run("flag wins over env", func(t *testing.T) {
+		t.Setenv(envvars.CliProfile, "tenant_env")
+		inv, err := BootstrapInvocationContext([]string{"--profile", "tenant_flag", "whoami"})
+		if err != nil {
+			t.Fatalf("unexpected err: %v", err)
+		}
+		if inv.Profile != "tenant_flag" {
+			t.Errorf("got %q, want tenant_flag", inv.Profile)
+		}
+		if !inv.ProfileFromFlag {
+			t.Errorf("ProfileFromFlag = false, want true")
+		}
+	})
+	t.Run("explicit empty flag clears env selection", func(t *testing.T) {
+		t.Setenv(envvars.CliProfile, "tenant_env")
+		inv, err := BootstrapInvocationContext([]string{"--profile=", "whoami"})
+		if err != nil {
+			t.Fatalf("unexpected err: %v", err)
+		}
+		if inv.Profile != "" {
+			t.Errorf("got %q, want empty", inv.Profile)
+		}
+		if !inv.ProfileFromFlag {
+			t.Errorf("ProfileFromFlag = false, want true")
+		}
+	})
+	t.Run("env used when flag absent", func(t *testing.T) {
+		t.Setenv(envvars.CliProfile, "tenant_env")
+		inv, err := BootstrapInvocationContext([]string{"whoami"})
+		if err != nil {
+			t.Fatalf("unexpected err: %v", err)
+		}
+		if inv.Profile != "tenant_env" {
+			t.Errorf("got %q, want tenant_env", inv.Profile)
+		}
+		if inv.ProfileFromFlag {
+			t.Errorf("ProfileFromFlag = true, want false")
+		}
+	})
+	t.Run("empty when neither set", func(t *testing.T) {
+		t.Setenv(envvars.CliProfile, "")
+		inv, err := BootstrapInvocationContext([]string{"whoami"})
+		if err != nil {
+			t.Fatalf("unexpected err: %v", err)
+		}
+		if inv.Profile != "" {
+			t.Errorf("got %q, want empty", inv.Profile)
+		}
+		if inv.ProfileFromFlag {
+			t.Errorf("ProfileFromFlag = true, want false")
+		}
+	})
+}
diff --git a/cmd/config/config_test.go b/cmd/config/config_test.go
index 9f0f3da62c..074100b00d 100644
--- a/cmd/config/config_test.go
+++ b/cmd/config/config_test.go
@@ -84,6 +84,16 @@ func TestConfigShowCmd_FlagParsing(t *testing.T) {
 	}
 }
 
+func TestConfigShowHelpClarifiesSavedConfig(t *testing.T) {
+	cmd := NewCmdConfigShow(nil, nil)
+	if !strings.Contains(cmd.Short, "saved config") {
+		t.Errorf("config show short = %q, want saved config", cmd.Short)
+	}
+	if !strings.Contains(cmd.Long, "lark-cli whoami --json") {
+		t.Errorf("config show help missing whoami route")
+	}
+}
+
 func TestConfigShowRun_NotConfiguredReturnsStructuredError(t *testing.T) {
 	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
 
@@ -106,6 +116,77 @@ func TestConfigShowRun_NotConfiguredReturnsStructuredError(t *testing.T) {
 	}
 }
 
+// config show promises "saved config, not current usage" (help + skill
+// routing): the session profile (--profile / LARKSUITE_CLI_PROFILE) must not
+// change what it shows.
+func TestConfigShowRun_IgnoresSessionProfile(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	multi := &core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{
+			{Name: "tenant_a", AppId: "cli_a", AppSecret: core.PlainSecret("your-secret-a"), Brand: core.BrandFeishu},
+			{Name: "tenant_b", AppId: "cli_b", AppSecret: core.PlainSecret("your-secret-b"), Brand: core.BrandFeishu},
+		},
+	}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	f, stdout, _, _ := cmdutil.TestFactory(t, nil)
+	f.Invocation.Profile = "tenant_b" // session selection must not leak in
+
+	if err := configShowRun(&ConfigShowOptions{Factory: f}); err != nil {
+		t.Fatalf("configShowRun: %v", err)
+	}
+	out := stdout.String()
+	if !strings.Contains(out, `"cli_a"`) || !strings.Contains(out, `"tenant_a"`) {
+		t.Fatalf("output = %s, want the saved default tenant_a/cli_a", out)
+	}
+	if strings.Contains(out, `"cli_b"`) {
+		t.Fatalf("output = %s, session profile tenant_b must not change saved-config view", out)
+	}
+}
+
+// engagedEnvStub simulates a fully engaged external credential provider.
+type engagedEnvStub struct{}
+
+func (engagedEnvStub) Name() string  { return "env" }
+func (engagedEnvStub) Priority() int { return 10 }
+func (engagedEnvStub) ResolveAccount(context.Context) (*extcred.Account, error) {
+	return &extcred.Account{AppID: "cli_env", AppSecret: "your-password"}, nil // managed takeover
+}
+func (engagedEnvStub) ResolveToken(context.Context, extcred.TokenSpec) (*extcred.Token, error) {
+	return nil, nil
+}
+
+// config show inspects the SAVED config only, so the parent command's
+// external-credential gate must not apply: even with a fully engaged direct
+// env credential, `config show` still answers from the saved config.
+func TestConfigShow_BypassesExternalCredentialGate(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	multi := &core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{{
+			Name: "tenant_a", AppId: "cli_a", AppSecret: core.PlainSecret("your-secret-a"), Brand: core.BrandFeishu,
+		}},
+	}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	f, stdout, _, _ := cmdutil.TestFactory(t, nil)
+	f.Credential = credential.NewCredentialProvider([]extcred.Provider{engagedEnvStub{}}, nil, nil, nil)
+
+	cmd := NewCmdConfig(f)
+	cmd.SetArgs([]string{"show"})
+	if err := cmd.Execute(); err != nil {
+		t.Fatalf("config show must bypass the external-credential gate: %v", err)
+	}
+	if out := stdout.String(); !strings.Contains(out, `"cli_a"`) {
+		t.Fatalf("output = %s, want the saved config shown", out)
+	}
+}
+
 func TestConfigShowRun_NoActiveProfileReturnsStructuredError(t *testing.T) {
 	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
 	multi := &core.MultiAppConfig{
@@ -481,7 +562,8 @@ func TestConfigBlockedByExternalProvider(t *testing.T) {
 	}{
 		{"init", []string{"init", "--app-id", "x", "--app-secret-stdin"}},
 		{"remove", []string{"remove"}},
-		{"show", []string{"show"}},
+		// "show" is deliberately absent: it inspects the SAVED config only
+		// and bypasses this gate (TestConfigShow_BypassesExternalCredentialGate).
 		{"default-as", []string{"default-as", "user"}},
 		{"strict-mode", []string{"strict-mode", "off"}},
 	}
diff --git a/cmd/config/show.go b/cmd/config/show.go
index 5526f0254a..4bcf8d335c 100644
--- a/cmd/config/show.go
+++ b/cmd/config/show.go
@@ -27,7 +27,16 @@ func NewCmdConfigShow(f *cmdutil.Factory, runF func(*ConfigShowOptions) error) *
 
 	cmd := &cobra.Command{
 		Use:   "show",
-		Short: "Show current configuration",
+		Short: "Show saved config",
+		Long:  "Shows saved config. To see the app/profile lark-cli is using now, run `lark-cli whoami --json`.",
+		// Override parent's RequireBuiltinCredentialProvider check: this
+		// command reads the SAVED config only (its own help promises "saved
+		// config, not current usage"), so the currently effective credential
+		// source — external or otherwise — must not gate it.
+		PersistentPreRunE: func(c *cobra.Command, _ []string) error {
+			c.SilenceUsage = true
+			return nil
+		},
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if runF != nil {
 				return runF(opts)
@@ -53,7 +62,10 @@ func configShowRun(opts *ConfigShowOptions) error {
 	if config == nil || len(config.Apps) == 0 {
 		return core.NotConfiguredError()
 	}
-	app := config.CurrentAppConfig(f.Invocation.Profile)
+	// Saved config only: the session profile (--profile / LARKSUITE_CLI_PROFILE)
+	// must not change what this command shows — the help and skill routing
+	// promise "saved config, not current usage" (use whoami for that).
+	app := config.CurrentAppConfig("")
 	if app == nil {
 		return errs.NewConfigError(errs.SubtypeNotConfigured, "no active profile").WithHint("run: lark-cli profile list")
 	}
diff --git a/cmd/event/consume_test.go b/cmd/event/consume_test.go
index ff0906fad0..08b4326ff0 100644
--- a/cmd/event/consume_test.go
+++ b/cmd/event/consume_test.go
@@ -110,8 +110,20 @@ func (failingTokenResolver) ResolveToken(_ context.Context, _ credential.TokenSp
 	return nil, errors.New("backend unavailable")
 }
 
+type eventTestAccountResolver struct {
+	appID string
+}
+
+func (r eventTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID}, nil
+}
+
+func newEventTestCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, eventTestAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 func factoryWithResolver(r credential.DefaultTokenResolver) *cmdutil.Factory {
-	return &cmdutil.Factory{Credential: credential.NewCredentialProvider(nil, nil, r, nil)}
+	return &cmdutil.Factory{Credential: newEventTestCredentialProvider("cli_x", r)}
 }
 
 func TestResolveTenantToken_EmptyTokenResult(t *testing.T) {
diff --git a/cmd/event/runtime_test.go b/cmd/event/runtime_test.go
index 67f2bea1c2..06729c8c3f 100644
--- a/cmd/event/runtime_test.go
+++ b/cmd/event/runtime_test.go
@@ -44,7 +44,7 @@ func newTestConsumeRuntime(rt http.RoundTripper) *consumeRuntime {
 		client: &client.APIClient{
 			SDK:        sdk,
 			ErrOut:     io.Discard,
-			Credential: credential.NewCredentialProvider(nil, nil, &staticTokenResolver{}, nil),
+			Credential: newEventTestCredentialProvider("test-app", &staticTokenResolver{}),
 			Config:     &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu},
 		},
 		accessIdentity: core.AsBot,
diff --git a/cmd/profile/list.go b/cmd/profile/list.go
index 5b0234c2c9..f19c463402 100644
--- a/cmd/profile/list.go
+++ b/cmd/profile/list.go
@@ -17,11 +17,14 @@ import (
 )
 
 // profileListItem is the JSON output for a single profile entry.
+// `default` (formerly `active`, renamed in this feature as a declared
+// breaking change) marks the saved default profile — never the identity
+// effective for the current invocation; that is whoami's job.
 type profileListItem struct {
 	Name        string         `json:"name"`
 	AppID       string         `json:"appId"`
 	Brand       core.LarkBrand `json:"brand"`
-	Active      bool           `json:"active"`
+	Default     bool           `json:"default"`
 	User        string         `json:"user,omitempty"`
 	TokenStatus string         `json:"tokenStatus,omitempty"`
 }
@@ -30,7 +33,8 @@ type profileListItem struct {
 func NewCmdProfileList(f *cmdutil.Factory) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "list",
-		Short: "List all profiles",
+		Short: "List saved profiles",
+		Long:  "Lists saved profiles. To see the app/profile lark-cli is using now, run `lark-cli whoami --json`.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return profileListRun(f)
 		},
@@ -53,7 +57,7 @@ func profileListRun(f *cmdutil.Factory) error {
 		return nil
 	}
 
-	// Intentionally uses "" to show the persistent active profile, not the ephemeral --profile override.
+	// Intentionally uses "" to show the saved default profile, not the ephemeral --profile override.
 	currentApp := multi.CurrentAppConfig("")
 	currentName := ""
 	if currentApp != nil {
@@ -66,10 +70,10 @@ func profileListRun(f *cmdutil.Factory) error {
 		name := app.ProfileName()
 
 		item := profileListItem{
-			Name:   name,
-			AppID:  app.AppId,
-			Brand:  app.Brand,
-			Active: name == currentName,
+			Name:    name,
+			AppID:   app.AppId,
+			Brand:   app.Brand,
+			Default: name == currentName,
 		}
 
 		if len(app.Users) > 0 {
diff --git a/cmd/profile/profile.go b/cmd/profile/profile.go
index 2216a4f391..9373c99169 100644
--- a/cmd/profile/profile.go
+++ b/cmd/profile/profile.go
@@ -14,6 +14,17 @@ func NewCmdProfile(f *cmdutil.Factory) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "profile",
 		Short: "Manage configuration profiles",
+		Long: `Profiles are named app identities managed by lark-cli.
+
+Identity diagnostics and profile selection:
+  lark-cli whoami --json       Show the app/profile lark-cli is using now.
+  lark-cli auth status --json --verify  Verify OAuth login and token state.
+  --profile <name>             Use a profile for this command only.
+  LARKSUITE_CLI_PROFILE        Use a profile for the current shell / agent session.
+  config show / profile list   Inspect saved config, not current usage.
+  unset LARKSUITE_CLI_PROFILE  Clear the session profile and fall back to direct app env or configured default.
+
+A selected profile takes precedence over matching direct env credentials and tokens.`,
 	}
 	cmdutil.DisableAuthCheck(cmd)
 	cmdutil.SetTips(cmd, []string{
diff --git a/cmd/profile/profile_test.go b/cmd/profile/profile_test.go
index 472a803bf6..f776f6050f 100644
--- a/cmd/profile/profile_test.go
+++ b/cmd/profile/profile_test.go
@@ -306,14 +306,24 @@ func TestProfileListRun_OutputsProfiles(t *testing.T) {
 	if err := json.Unmarshal(stdout.Bytes(), &got); err != nil {
 		t.Fatalf("Unmarshal() error = %v; output=%s", err, stdout.String())
 	}
+	raw := stdout.String()
+	// `active` is renamed to `default` as a declared breaking change: keeping
+	// a permanently mirrored alias would keep misleading agents into reading
+	// it as the currently effective identity (whoami's job).
+	if strings.Contains(raw, `"active"`) {
+		t.Fatalf("profile list output contains renamed active field: %s", raw)
+	}
+	if !strings.Contains(raw, `"default"`) {
+		t.Fatalf("profile list output missing default field: %s", raw)
+	}
 	if len(got) != 2 {
 		t.Fatalf("len(got) = %d, want 2", len(got))
 	}
-	if got[0].Name != "default" || !got[0].Active {
-		t.Fatalf("got[0] = %#v, want active default profile", got[0])
+	if got[0].Name != "default" || !got[0].Default {
+		t.Fatalf("got[0] = %#v, want configured default profile", got[0])
 	}
-	if got[1].Name != "target" || got[1].Active {
-		t.Fatalf("got[1] = %#v, want inactive target profile", got[1])
+	if got[1].Name != "target" || got[1].Default {
+		t.Fatalf("got[1] = %#v, want non-default target profile", got[1])
 	}
 }
 
@@ -627,6 +637,39 @@ func TestProfileRemoveRun_ValidationErrors(t *testing.T) {
 	})
 }
 
+// TestProfileHelpHasSelectionSection asserts `profile --help` documents the
+// per-invocation flag and session-scoped env var for selecting a profile, so
+// users and AI agents can find LARKSUITE_CLI_PROFILE without reading source.
+func TestProfileHelpHasSelectionSection(t *testing.T) {
+	cmd := NewCmdProfile(nil)
+	if !strings.Contains(cmd.Long, "Identity diagnostics and profile selection:") {
+		t.Errorf("profile --help missing identity diagnostics and profile selection section")
+	}
+	if !strings.Contains(cmd.Long, "LARKSUITE_CLI_PROFILE") {
+		t.Errorf("profile --help missing LARKSUITE_CLI_PROFILE")
+	}
+	if !strings.Contains(cmd.Long, "lark-cli whoami --json") {
+		t.Errorf("profile --help missing whoami identity route")
+	}
+	if !strings.Contains(cmd.Long, "config show / profile list") {
+		t.Errorf("profile --help missing saved-config boundary")
+	}
+	const precedence = "A selected profile takes precedence over matching direct env credentials and tokens."
+	if !strings.Contains(cmd.Long, precedence) {
+		t.Errorf("profile --help missing precedence statement %q", precedence)
+	}
+}
+
+func TestProfileListHelpClarifiesSavedProfiles(t *testing.T) {
+	cmd := NewCmdProfileList(nil)
+	if !strings.Contains(cmd.Short, "saved profiles") {
+		t.Errorf("profile list short = %q, want saved profiles", cmd.Short)
+	}
+	if !strings.Contains(cmd.Long, "lark-cli whoami --json") {
+		t.Errorf("profile list help missing whoami route")
+	}
+}
+
 func TestProfileListRun_InvalidConfigReturnsValidationError(t *testing.T) {
 	dir := setupProfileConfigDir(t)
 	if err := os.WriteFile(filepath.Join(dir, "config.json"), []byte("{invalid json"), 0600); err != nil {
diff --git a/cmd/whoami/whoami.go b/cmd/whoami/whoami.go
index d5b4b387f9..6b5b973b70 100644
--- a/cmd/whoami/whoami.go
+++ b/cmd/whoami/whoami.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/larksuite/cli/internal/cmdutil"
 	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/credential"
 	"github.com/larksuite/cli/internal/identitydiag"
 	"github.com/larksuite/cli/internal/output"
 )
@@ -33,6 +34,15 @@ type whoamiResult struct {
 	TokenStatus    string         `json:"tokenStatus"`
 	OnBehalfOf     *delegatedUser `json:"onBehalfOf,omitempty"`
 	Hint           string         `json:"hint,omitempty"`
+
+	// CredentialSource, Explicit, and DirectCredentialEnv surface the cached
+	// credential.IdentitySelection computed during resolution (not re-inferred
+	// here). On the non-env extension-provider path CredentialSource is
+	// "extension:<provider>" (e.g. "extension:sidecar"); an empty value only
+	// means the selection was never resolved.
+	CredentialSource    string                         `json:"credentialSource"`
+	Explicit            bool                           `json:"explicit"`
+	DirectCredentialEnv credential.DirectCredentialEnv `json:"directCredentialEnv"`
 }
 
 // delegatedUser is the user a user-identity acts on behalf of.
@@ -58,6 +68,10 @@ func NewCmdWhoami(f *cmdutil.Factory) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "whoami",
 		Short: "Show the current effective identity, app, profile, and token status (JSON)",
+		Long: `Show the effective app identity used by this invocation. This is not OAuth login status;
+use ` + "`lark-cli auth status --json`" + ` for OAuth user/token state.
+The JSON output includes credentialSource, appId, brand, and whether direct app credential
+env is present and matches the selected profile.`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return whoamiRun(cmd, opts)
 		},
@@ -97,7 +111,17 @@ func whoamiRun(cmd *cobra.Command, opts *Options) error {
 		f.ResolveStrictMode(ctx).ForcedIdentity(),
 	)
 	diag := identitydiag.Diagnose(ctx, f, cfg, false)
-	res := buildResult(cfg, as, source, diag)
+	// Read the cached selection computed during resolution; never re-infer it
+	// here. A resolution failure (e.g. under a non-env extension provider that
+	// doesn't populate a selection) degrades to the zero value rather than
+	// regressing whoami's own error/diagnostic path above.
+	var selection credential.IdentitySelection
+	if f.Credential != nil {
+		if sel, err := f.Credential.Selection(ctx); err == nil {
+			selection = sel
+		}
+	}
+	res := buildResult(cfg, as, source, diag, selection)
 	output.PrintJson(f.IOStreams.Out, res)
 	return nil
 }
@@ -122,18 +146,23 @@ func resolveSource(changedAs bool, flagAs core.Identity, autoDetected bool, stri
 
 // buildResult maps the resolved identity and local diagnostics into the output.
 // ResolveAs only ever returns user or bot, so the default branch handles user.
-func buildResult(cfg *core.CliConfig, as core.Identity, source string, diag identitydiag.Result) *whoamiResult {
+// selection is the cached credential.IdentitySelection from resolution; it is
+// read as-is, never recomputed.
+func buildResult(cfg *core.CliConfig, as core.Identity, source string, diag identitydiag.Result, selection credential.IdentitySelection) *whoamiResult {
 	defaultAs := cfg.DefaultAs
 	if defaultAs == "" {
 		defaultAs = core.AsAuto
 	}
 	res := &whoamiResult{
-		Profile:        cfg.ProfileName,
-		AppID:          cfg.AppID,
-		Brand:          cfg.Brand,
-		DefaultAs:      string(defaultAs),
-		Identity:       string(as),
-		IdentitySource: source,
+		Profile:             cfg.ProfileName,
+		AppID:               cfg.AppID,
+		Brand:               cfg.Brand,
+		DefaultAs:           string(defaultAs),
+		Identity:            string(as),
+		IdentitySource:      source,
+		CredentialSource:    string(selection.Source),
+		Explicit:            selection.Explicit(),
+		DirectCredentialEnv: selection.DirectCredentialEnv,
 	}
 	// Use the diagnosed hint as-is: it is tailored to the credential source, so
 	// it never says "auth login" when that is blocked under an external provider.
diff --git a/cmd/whoami/whoami_test.go b/cmd/whoami/whoami_test.go
index 0888623974..6d1b29a6ef 100644
--- a/cmd/whoami/whoami_test.go
+++ b/cmd/whoami/whoami_test.go
@@ -15,10 +15,13 @@ import (
 
 	"github.com/larksuite/cli/errs"
 	extcred "github.com/larksuite/cli/extension/credential"
+	envprovider "github.com/larksuite/cli/extension/credential/env"
 	"github.com/larksuite/cli/internal/cmdutil"
 	"github.com/larksuite/cli/internal/core"
 	"github.com/larksuite/cli/internal/credential"
+	"github.com/larksuite/cli/internal/envvars"
 	"github.com/larksuite/cli/internal/identitydiag"
+	"github.com/larksuite/cli/internal/keychain"
 )
 
 func TestResolveSource(t *testing.T) {
@@ -52,7 +55,7 @@ func TestBuildResult_UserValid(t *testing.T) {
 	diag := identitydiag.Result{
 		User: identitydiag.Identity{Available: true, Status: "ready", TokenStatus: "valid", OpenID: "ou_x", UserName: "Alice"},
 	}
-	r := buildResult(cfg, core.AsUser, "auto_detect", diag)
+	r := buildResult(cfg, core.AsUser, "auto_detect", diag, credential.IdentitySelection{})
 
 	if r.Identity != "user" || r.IdentitySource != "auto_detect" {
 		t.Fatalf("identity/source = %q/%q", r.Identity, r.IdentitySource)
@@ -77,7 +80,7 @@ func TestBuildResult_UserMissingToken(t *testing.T) {
 	diag := identitydiag.Result{
 		User: identitydiag.Identity{Available: false, Status: "missing", Hint: "run: lark-cli auth login --help"}, // never logged in
 	}
-	r := buildResult(cfg, core.AsUser, "auto_detect", diag)
+	r := buildResult(cfg, core.AsUser, "auto_detect", diag, credential.IdentitySelection{})
 
 	if r.Available {
 		t.Fatalf("available = true, want false")
@@ -100,7 +103,7 @@ func TestBuildResult_BotReady(t *testing.T) {
 	diag := identitydiag.Result{
 		Bot: identitydiag.Identity{Available: true, Status: "ready"},
 	}
-	r := buildResult(cfg, core.AsBot, "default_as", diag)
+	r := buildResult(cfg, core.AsBot, "default_as", diag, credential.IdentitySelection{})
 
 	if r.Identity != "bot" || r.IdentitySource != "default_as" {
 		t.Fatalf("identity/source = %q/%q", r.Identity, r.IdentitySource)
@@ -121,7 +124,7 @@ func TestBuildResult_BotNotConfigured(t *testing.T) {
 	diag := identitydiag.Result{
 		Bot: identitydiag.Identity{Available: false, Status: "not_configured", Hint: "run: lark-cli config --help"},
 	}
-	r := buildResult(cfg, core.AsBot, "auto_detect", diag)
+	r := buildResult(cfg, core.AsBot, "auto_detect", diag, credential.IdentitySelection{})
 
 	if r.Available {
 		t.Fatalf("available = true, want false")
@@ -318,3 +321,94 @@ func TestWhoami_ExternalProvider_UserHintNotKeychain(t *testing.T) {
 		t.Fatalf("hint should explain external management: %q", got.Hint)
 	}
 }
+
+// noopWhoamiKeychain is a no-op KeychainAccess; the profile below uses a
+// plaintext secret, so no keychain lookup is actually required.
+type noopWhoamiKeychain struct{}
+
+func (noopWhoamiKeychain) Get(service, account string) (string, error) { return "", nil }
+func (noopWhoamiKeychain) Set(service, account, value string) error    { return nil }
+func (noopWhoamiKeychain) Remove(service, account string) error        { return nil }
+
+// credentialSourceSecret is the profile secret written to config for
+// TestWhoamiIncludesCredentialSource. It must never leak into whoami's output
+// (security: never leak a secret).
+const credentialSourceSecret = "test-secret"
+
+// profileSelectionFactory builds a Factory whose CredentialProvider resolves
+// an explicit profile ("tenant_a") supplied via the LARKSUITE_CLI_PROFILE env
+// fallback (not --profile), so Selection().Source resolves to
+// env:LARKSUITE_CLI_PROFILE and Explicit() is true, with no direct
+// app-credential env vars present.
+func profileSelectionFactory(t *testing.T) (*cmdutil.Factory, *bytes.Buffer) {
+	t.Helper()
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+
+	multi := &core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{{
+			Name:      "tenant_a",
+			AppId:     "cli_a",
+			AppSecret: core.PlainSecret(credentialSourceSecret),
+			Brand:     core.BrandFeishu,
+		}},
+	}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	defaultAcct := credential.NewDefaultAccountProvider(func() keychain.KeychainAccess { return noopWhoamiKeychain{} }, "tenant_a")
+	cred := credential.NewCredentialProvider([]extcred.Provider{&envprovider.Provider{}}, defaultAcct, nil, nil)
+	cred.WithProfileFromEnv("tenant_a")
+
+	cfg := &core.CliConfig{ProfileName: "tenant_a", AppID: "cli_a", AppSecret: credentialSourceSecret, Brand: core.BrandFeishu}
+	out := &bytes.Buffer{}
+	f := &cmdutil.Factory{
+		Config:     func() (*core.CliConfig, error) { return cfg, nil },
+		Credential: cred,
+		IOStreams:  &cmdutil.IOStreams{Out: out, ErrOut: &bytes.Buffer{}},
+	}
+	return f, out
+}
+
+// TestWhoamiIncludesCredentialSource locks in the diagnostic fields surfaced
+// from the cached credential.IdentitySelection: credentialSource,
+// explicit, and directCredentialEnv. whoami must read the cached selection
+// as-is, not re-infer it.
+func TestWhoamiIncludesCredentialSource(t *testing.T) {
+	f, out := profileSelectionFactory(t)
+
+	cmd := NewCmdWhoami(f)
+	cmd.SetArgs([]string{})
+	if err := cmd.Execute(); err != nil {
+		t.Fatalf("Execute() error = %v", err)
+	}
+
+	raw := out.String()
+	if strings.Contains(raw, credentialSourceSecret) {
+		t.Fatalf("whoami output leaked the profile secret: %s", raw)
+	}
+
+	var got whoamiResult
+	if err := json.Unmarshal(out.Bytes(), &got); err != nil {
+		t.Fatalf("json.Unmarshal() error = %v\n%s", err, raw)
+	}
+	if got.CredentialSource != string(credential.SourceEnvProfile) {
+		t.Fatalf("credentialSource = %q, want %q", got.CredentialSource, credential.SourceEnvProfile)
+	}
+	if !got.Explicit {
+		t.Fatalf("explicit = false, want true")
+	}
+	if got.DirectCredentialEnv.Present {
+		t.Fatalf("directCredentialEnv.present = true, want false: %#v", got.DirectCredentialEnv)
+	}
+	if !strings.Contains(raw, `"credentialSource": "env:LARKSUITE_CLI_PROFILE"`) {
+		t.Fatalf("raw JSON missing credentialSource literal: %s", raw)
+	}
+	if got.DirectCredentialEnv.Present || len(got.DirectCredentialEnv.Keys) != 0 ||
+		got.DirectCredentialEnv.AppID != "" || got.DirectCredentialEnv.Matched || got.DirectCredentialEnv.ConflictsWithProfile {
+		t.Fatalf("directCredentialEnv = %#v, want only present:false set", got.DirectCredentialEnv)
+	}
+}
diff --git a/errs/ERROR_CONTRACT.md b/errs/ERROR_CONTRACT.md
index 5262ce58dd..383a640536 100644
--- a/errs/ERROR_CONTRACT.md
+++ b/errs/ERROR_CONTRACT.md
@@ -67,6 +67,17 @@ Typed errors render to **stderr** as one JSON object per process exit:
 | `error.params` | per-Subtype-stable | per-parameter validation detail array (`ValidationError`); see **Validation parameters** |
 | per-Subtype extension fields | per-Subtype-stable | e.g. `missing_scopes`, `console_url`, `challenge_url` |
 
+Credential/identity-selection extension fields (per-Subtype-stable):
+
+| Field | Carrier | Subtypes | Notes |
+|-------|---------|----------|-------|
+| `missing_keys` | `ConfigError` | `app_credential_incomplete` | env var NAMES that must all be set; never values |
+| `required_any_of` | `ConfigError` | `app_credential_incomplete` | env var NAMES where any one completes the credential; mutually exclusive with `missing_keys` |
+| `profile` | `ConfigError` | `profile_not_found`, `profile_secret_invalid` | requested profile name |
+| `app_id` | `ConfigError` | `profile_secret_invalid` | plaintext app id; never a secret |
+| `credential_source` | `ConfigError` | `profile_not_found`, `no_active_profile` | how the identity was (not) chosen: `flag:--profile` \| `env:LARKSUITE_CLI_PROFILE` \| `config` |
+| `profile_app_id`, `env_app_id` | `ValidationError` | `profile_app_credential_conflict` | the two conflicting plaintext app ids |
+
 `SecurityPolicyError` renders through the same typed envelope as every
 other category. `error.type` is `"policy"`, `error.subtype` is one of
 `challenge_required` / `access_denied`, and process exit is `6` via
diff --git a/errs/marshal_test.go b/errs/marshal_test.go
index b495ad78f4..c9de3983c6 100644
--- a/errs/marshal_test.go
+++ b/errs/marshal_test.go
@@ -136,6 +136,79 @@ func TestConfigError_MarshalJSON(t *testing.T) {
 	}
 }
 
+func TestConfigError_ProfileFieldsMarshalJSON(t *testing.T) {
+	ce := NewConfigError(SubtypeAppCredentialIncomplete, "incomplete").
+		WithMissingKeys("LARKSUITE_CLI_APP_ID", "LARKSUITE_CLI_APP_SECRET").
+		WithRequiredAnyOf("LARKSUITE_CLI_APP_SECRET", "LARKSUITE_CLI_USER_ACCESS_TOKEN").
+		WithProfile("work").
+		WithAppID("cli_abc").
+		WithCredentialSource("flag:--profile")
+	b, err := json.Marshal(ce)
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := string(b)
+	for _, want := range []string{
+		`"type":"config"`,
+		`"subtype":"app_credential_incomplete"`,
+		`"missing_keys":["LARKSUITE_CLI_APP_ID","LARKSUITE_CLI_APP_SECRET"]`,
+		`"required_any_of":["LARKSUITE_CLI_APP_SECRET","LARKSUITE_CLI_USER_ACCESS_TOKEN"]`,
+		`"profile":"work"`,
+		`"app_id":"cli_abc"`,
+		`"credential_source":"flag:--profile"`,
+	} {
+		if !strings.Contains(s, want) {
+			t.Errorf("missing %q in %s", want, s)
+		}
+	}
+
+	// omitempty: unset fields must not appear on the wire.
+	empty := NewConfigError(SubtypeProfileNotFound, "x")
+	b2, err := json.Marshal(empty)
+	if err != nil {
+		t.Fatal(err)
+	}
+	s2 := string(b2)
+	for _, notWant := range []string{`"missing_keys"`, `"required_any_of"`, `"profile"`, `"app_id"`, `"credential_source"`} {
+		if strings.Contains(s2, notWant) {
+			t.Errorf("%q should be omitted when empty; got %s", notWant, s2)
+		}
+	}
+}
+
+func TestValidationError_ProfileConflictMarshalJSON(t *testing.T) {
+	ve := NewValidationError(SubtypeProfileAppCredentialConflict, "conflict").
+		WithProfileAppConflict("cli_profile", "cli_env")
+	b, err := json.Marshal(ve)
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := string(b)
+	for _, want := range []string{
+		`"type":"validation"`,
+		`"subtype":"profile_app_credential_conflict"`,
+		`"profile_app_id":"cli_profile"`,
+		`"env_app_id":"cli_env"`,
+	} {
+		if !strings.Contains(s, want) {
+			t.Errorf("missing %q in %s", want, s)
+		}
+	}
+
+	// omitempty: unset conflict fields must not appear on the wire.
+	empty := NewValidationError(SubtypeInvalidArgument, "x")
+	b2, err := json.Marshal(empty)
+	if err != nil {
+		t.Fatal(err)
+	}
+	s2 := string(b2)
+	for _, notWant := range []string{`"profile_app_id"`, `"env_app_id"`} {
+		if strings.Contains(s2, notWant) {
+			t.Errorf("%q should be omitted when empty; got %s", notWant, s2)
+		}
+	}
+}
+
 func TestNetworkError_MarshalJSON(t *testing.T) {
 	ne := &NetworkError{
 		Problem: Problem{Category: CategoryNetwork, Subtype: SubtypeNetworkTimeout, Message: "dial timeout"},
diff --git a/errs/subtypes.go b/errs/subtypes.go
index df0cf8ab85..b84c5266b9 100644
--- a/errs/subtypes.go
+++ b/errs/subtypes.go
@@ -12,8 +12,9 @@ const (
 
 // CategoryValidation subtypes
 const (
-	SubtypeInvalidArgument    Subtype = "invalid_argument"    // user-supplied flag / arg failed validation (gRPC INVALID_ARGUMENT alignment)
-	SubtypeFailedPrecondition Subtype = "failed_precondition" // request is valid but the system/resource state is not in the state required to execute; caller must change state (not retry) — e.g. ambiguous remote mapping (gRPC FAILED_PRECONDITION alignment)
+	SubtypeInvalidArgument              Subtype = "invalid_argument"                // user-supplied flag / arg failed validation (gRPC INVALID_ARGUMENT alignment)
+	SubtypeFailedPrecondition           Subtype = "failed_precondition"             // request is valid but the system/resource state is not in the state required to execute; caller must change state (not retry) — e.g. ambiguous remote mapping (gRPC FAILED_PRECONDITION alignment)
+	SubtypeProfileAppCredentialConflict Subtype = "profile_app_credential_conflict" // profile and direct app env both set but app_id differs
 )
 
 // CategoryAuthentication subtypes
@@ -41,9 +42,13 @@ const (
 
 // CategoryConfig subtypes
 const (
-	SubtypeInvalidClient Subtype = "invalid_client" // app_id / app_secret incorrect (RFC 6749 §5.2 alignment)
-	SubtypeNotConfigured Subtype = "not_configured" // local config file absent (user has not run `config init`)
-	SubtypeInvalidConfig Subtype = "invalid_config" // local config file present but malformed
+	SubtypeInvalidClient           Subtype = "invalid_client"            // app_id / app_secret incorrect (RFC 6749 §5.2 alignment)
+	SubtypeNotConfigured           Subtype = "not_configured"            // local config file absent (user has not run `config init`)
+	SubtypeInvalidConfig           Subtype = "invalid_config"            // local config file present but malformed
+	SubtypeProfileNotFound         Subtype = "profile_not_found"         // --profile / LARKSUITE_CLI_PROFILE points to a nonexistent profile
+	SubtypeNoActiveProfile         Subtype = "no_active_profile"         // no active identity input and no usable default profile
+	SubtypeAppCredentialIncomplete Subtype = "app_credential_incomplete" // direct app env missing app_id or app_secret
+	SubtypeProfileSecretInvalid    Subtype = "profile_secret_invalid"    // profile exists but its secret cannot be resolved locally
 )
 
 // CategoryNetwork subtypes
diff --git a/errs/types.go b/errs/types.go
index 94b67d65f7..027c9d5432 100644
--- a/errs/types.go
+++ b/errs/types.go
@@ -61,9 +61,11 @@ type TypedError interface {
 // it is intentionally not serialized.
 type ValidationError struct {
 	Problem
-	Param  string         `json:"param,omitempty"`
-	Params []InvalidParam `json:"params,omitempty"`
-	Cause  error          `json:"-"`
+	Param        string         `json:"param,omitempty"`
+	Params       []InvalidParam `json:"params,omitempty"`
+	ProfileAppID string         `json:"profile_app_id,omitempty"`
+	EnvAppID     string         `json:"env_app_id,omitempty"`
+	Cause        error          `json:"-"`
 }
 
 // InvalidParam is one structured validation diagnostic: the parameter that
@@ -150,6 +152,12 @@ func (e *ValidationError) WithCause(cause error) *ValidationError {
 	return e
 }
 
+func (e *ValidationError) WithProfileAppConflict(profileAppID, envAppID string) *ValidationError {
+	e.ProfileAppID = profileAppID
+	e.EnvAppID = envAppID
+	return e
+}
+
 // =========================== AuthenticationError =============================
 
 // AuthenticationError is the typed error for CategoryAuthentication.
@@ -315,8 +323,18 @@ func (e *PermissionError) WithCause(cause error) *PermissionError {
 // intentionally not serialized.
 type ConfigError struct {
 	Problem
-	Field string `json:"field,omitempty"`
-	Cause error  `json:"-"`
+	Field         string   `json:"field,omitempty"`
+	MissingKeys   []string `json:"missing_keys,omitempty"`
+	RequiredAnyOf []string `json:"required_any_of,omitempty"`
+	Profile       string   `json:"profile,omitempty"`
+	AppID         string   `json:"app_id,omitempty"`
+	// CredentialSource is the machine-readable App/credential selection source
+	// that produced this config error (e.g. "flag:--profile",
+	// "env:LARKSUITE_CLI_PROFILE", "config"). It is required on
+	// profile_not_found and no_active_profile so an agent can branch
+	// on how the identity was (or was not) chosen. It is never a secret.
+	CredentialSource string `json:"credential_source,omitempty"`
+	Cause            error  `json:"-"`
 }
 
 // Unwrap is nil-receiver safe; see ValidationError.Unwrap.
@@ -370,6 +388,34 @@ func (e *ConfigError) WithField(field string) *ConfigError {
 	return e
 }
 
+func (e *ConfigError) WithMissingKeys(keys ...string) *ConfigError {
+	e.MissingKeys = slices.Clone(keys)
+	return e
+}
+
+func (e *ConfigError) WithRequiredAnyOf(keys ...string) *ConfigError {
+	e.RequiredAnyOf = slices.Clone(keys)
+	return e
+}
+
+func (e *ConfigError) WithProfile(name string) *ConfigError {
+	e.Profile = name
+	return e
+}
+
+func (e *ConfigError) WithAppID(appID string) *ConfigError {
+	e.AppID = appID
+	return e
+}
+
+// WithCredentialSource records the machine-readable credential-selection source
+// on the wire (snake_case credential_source). The value is an enum string
+// (e.g. "flag:--profile", "config"), never a secret.
+func (e *ConfigError) WithCredentialSource(source string) *ConfigError {
+	e.CredentialSource = source
+	return e
+}
+
 func (e *ConfigError) WithCause(cause error) *ConfigError {
 	e.Cause = cause
 	return e
diff --git a/errs/types_test.go b/errs/types_test.go
index 8279c2e46b..baac931e53 100644
--- a/errs/types_test.go
+++ b/errs/types_test.go
@@ -643,3 +643,29 @@ func TestBuilderSetter_DefensiveCopy(t *testing.T) {
 		}
 	})
 }
+
+// ======================= Profile selection error subtypes =======================
+
+func TestConfigErrorProfileFields(t *testing.T) {
+	e := errs.NewConfigError(errs.SubtypeAppCredentialIncomplete, "incomplete").
+		WithMissingKeys("LARKSUITE_CLI_APP_ID").
+		WithCredentialSource("env:LARKSUITE_CLI_PROFILE")
+	p, ok := errs.ProblemOf(e)
+	if !ok || p.Subtype != errs.SubtypeAppCredentialIncomplete {
+		t.Fatalf("subtype mismatch: %+v", p)
+	}
+	if len(e.MissingKeys) != 1 || e.MissingKeys[0] != "LARKSUITE_CLI_APP_ID" {
+		t.Errorf("missing_keys not set: %v", e.MissingKeys)
+	}
+	if e.CredentialSource != "env:LARKSUITE_CLI_PROFILE" {
+		t.Errorf("credential_source not set: %q", e.CredentialSource)
+	}
+}
+
+func TestValidationErrorProfileConflict(t *testing.T) {
+	e := errs.NewValidationError(errs.SubtypeProfileAppCredentialConflict, "conflict").
+		WithProfileAppConflict("cli_profile", "cli_env")
+	if e.ProfileAppID != "cli_profile" || e.EnvAppID != "cli_env" {
+		t.Errorf("conflict fields not set: %q %q", e.ProfileAppID, e.EnvAppID)
+	}
+}
diff --git a/extension/credential/env/env.go b/extension/credential/env/env.go
index 5458125689..e45686433a 100644
--- a/extension/credential/env/env.go
+++ b/extension/credential/env/env.go
@@ -23,62 +23,88 @@ func (p *Provider) ResolveAccount(ctx context.Context) (*credential.Account, err
 	appSecret := os.Getenv(envvars.CliAppSecret)
 	hasUAT := os.Getenv(envvars.CliUserAccessToken) != ""
 	hasTAT := os.Getenv(envvars.CliTenantAccessToken) != ""
-	if appID == "" && appSecret == "" {
-		switch {
-		case hasUAT:
-			return nil, &credential.BlockError{Provider: "env", Reason: envvars.CliUserAccessToken + " is set but " + envvars.CliAppID + " is missing"}
-		case hasTAT:
-			return nil, &credential.BlockError{Provider: "env", Reason: envvars.CliTenantAccessToken + " is set but " + envvars.CliAppID + " is missing"}
-		default:
-			return nil, nil
-		}
-	}
-	if appID == "" {
-		return nil, &credential.BlockError{Provider: "env", Reason: envvars.CliAppSecret + " is set but " + envvars.CliAppID + " is missing"}
-	}
-	if appSecret == "" && !hasUAT && !hasTAT {
-		return nil, &credential.BlockError{
-			Provider: "env",
-			Reason:   envvars.CliAppID + " is set but no app secret or access token is available",
-		}
+	presentKeys := presentCredentialEnvKeys(appID, appSecret, hasUAT, hasTAT)
+	if len(presentKeys) == 0 {
+		return nil, nil
 	}
-	brand := credential.Brand(core.ParseBrand(os.Getenv(envvars.CliBrand)))
-	acct := &credential.Account{AppID: appID, AppSecret: appSecret, Brand: brand}
 
-	switch id := credential.Identity(os.Getenv(envvars.CliDefaultAs)); id {
-	case "", credential.IdentityAuto:
-		acct.DefaultAs = id
-	case credential.IdentityUser, credential.IdentityBot:
-		acct.DefaultAs = id
+	// Identity policy variables are validated whenever a direct credential
+	// input is present. Their errors must not be hidden by a later credential
+	// completeness check or profile arbitration.
+	defaultAs := credential.Identity(os.Getenv(envvars.CliDefaultAs))
+	switch defaultAs {
+	case "", credential.IdentityAuto, credential.IdentityUser, credential.IdentityBot:
 	default:
 		return nil, &credential.BlockError{
 			Provider: "env",
-			Reason:   fmt.Sprintf("invalid %s %q (want user, bot, or auto)", envvars.CliDefaultAs, id),
+			Reason:   fmt.Sprintf("invalid %s %q (want user, bot, or auto)", envvars.CliDefaultAs, defaultAs),
+			Code:     credential.BlockReasonInvalidPolicy,
+			Param:    envvars.CliDefaultAs,
 		}
 	}
 
-	// Explicit strict mode policy takes priority
-	switch strictMode := os.Getenv(envvars.CliStrictMode); strictMode {
+	strictMode := os.Getenv(envvars.CliStrictMode)
+	var supported credential.IdentitySupport
+	switch strictMode {
 	case "bot":
-		acct.SupportedIdentities = credential.SupportsBot
+		supported = credential.SupportsBot
 	case "user":
-		acct.SupportedIdentities = credential.SupportsUser
+		supported = credential.SupportsUser
 	case "off":
-		acct.SupportedIdentities = credential.SupportsAll
+		supported = credential.SupportsAll
 	case "":
-		// Infer from available tokens
 		if hasUAT {
-			acct.SupportedIdentities |= credential.SupportsUser
+			supported |= credential.SupportsUser
 		}
 		if hasTAT {
-			acct.SupportedIdentities |= credential.SupportsBot
+			supported |= credential.SupportsBot
 		}
 	default:
 		return nil, &credential.BlockError{
 			Provider: "env",
 			Reason:   fmt.Sprintf("invalid %s %q (want bot, user, or off)", envvars.CliStrictMode, strictMode),
+			Code:     credential.BlockReasonInvalidPolicy,
+			Param:    envvars.CliStrictMode,
+		}
+	}
+
+	if appID == "" && appSecret == "" {
+		switch {
+		case hasUAT:
+			return nil, incompleteCredentialError(
+				appID,
+				envvars.CliUserAccessToken+" is set but "+envvars.CliAppID+" is missing",
+				[]string{envvars.CliAppID}, nil, presentKeys)
+		case hasTAT:
+			return nil, incompleteCredentialError(
+				appID,
+				envvars.CliTenantAccessToken+" is set but "+envvars.CliAppID+" is missing",
+				[]string{envvars.CliAppID}, nil, presentKeys)
 		}
 	}
+	if appID == "" {
+		return nil, incompleteCredentialError(
+			appID,
+			envvars.CliAppSecret+" is set but "+envvars.CliAppID+" is missing",
+			[]string{envvars.CliAppID}, nil, presentKeys)
+	}
+	if appSecret == "" && !hasUAT && !hasTAT {
+		return nil, incompleteCredentialError(
+			appID,
+			envvars.CliAppID+" is set but no app secret or access token is available",
+			nil,
+			[]string{envvars.CliAppSecret, envvars.CliUserAccessToken, envvars.CliTenantAccessToken},
+			presentKeys)
+	}
+	brand := credential.Brand(core.ParseBrand(os.Getenv(envvars.CliBrand)))
+	acct := &credential.Account{
+		AppID:               appID,
+		AppSecret:           appSecret,
+		Brand:               brand,
+		DefaultAs:           defaultAs,
+		SupportedIdentities: supported,
+		Kind:                credential.AccountDirect,
+	}
 
 	if acct.DefaultAs == "" {
 		switch {
@@ -92,6 +118,35 @@ func (p *Provider) ResolveAccount(ctx context.Context) (*credential.Account, err
 	return acct, nil
 }
 
+func incompleteCredentialError(appID, reason string, missingKeys, requiredAnyOf, presentKeys []string) *credential.BlockError {
+	return &credential.BlockError{
+		Provider:      "env",
+		Reason:        reason,
+		Code:          credential.BlockReasonCredentialIncomplete,
+		MissingKeys:   missingKeys,
+		RequiredAnyOf: requiredAnyOf,
+		PresentKeys:   presentKeys,
+		AppID:         appID,
+	}
+}
+
+func presentCredentialEnvKeys(appID, appSecret string, hasUAT, hasTAT bool) []string {
+	var keys []string
+	if appID != "" {
+		keys = append(keys, envvars.CliAppID)
+	}
+	if appSecret != "" {
+		keys = append(keys, envvars.CliAppSecret)
+	}
+	if hasUAT {
+		keys = append(keys, envvars.CliUserAccessToken)
+	}
+	if hasTAT {
+		keys = append(keys, envvars.CliTenantAccessToken)
+	}
+	return keys
+}
+
 func (p *Provider) ResolveToken(ctx context.Context, req credential.TokenSpec) (*credential.Token, error) {
 	var envKey string
 	switch req.Type {
diff --git a/extension/credential/env/env_test.go b/extension/credential/env/env_test.go
index 096bd9fe29..ddaae85e26 100644
--- a/extension/credential/env/env_test.go
+++ b/extension/credential/env/env_test.go
@@ -6,6 +6,7 @@ package env
 import (
 	"context"
 	"errors"
+	"slices"
 	"strings"
 	"testing"
 
@@ -47,6 +48,22 @@ func TestResolveAccount_OnlyIDSet(t *testing.T) {
 	if !errors.As(err, &blockErr) {
 		t.Fatalf("expected BlockError, got %v", err)
 	}
+	if blockErr.Code != credential.BlockReasonCredentialIncomplete {
+		t.Fatalf("Code = %q, want %q", blockErr.Code, credential.BlockReasonCredentialIncomplete)
+	}
+	want := []string{envvars.CliAppSecret, envvars.CliUserAccessToken, envvars.CliTenantAccessToken}
+	if !slices.Equal(blockErr.RequiredAnyOf, want) {
+		t.Fatalf("RequiredAnyOf = %v, want %v", blockErr.RequiredAnyOf, want)
+	}
+	if len(blockErr.MissingKeys) != 0 {
+		t.Fatalf("MissingKeys = %v, want empty", blockErr.MissingKeys)
+	}
+	if !slices.Equal(blockErr.PresentKeys, []string{envvars.CliAppID}) {
+		t.Fatalf("PresentKeys = %v, want [%s]", blockErr.PresentKeys, envvars.CliAppID)
+	}
+	if blockErr.AppID != "cli_test" {
+		t.Fatalf("AppID = %q, want cli_test", blockErr.AppID)
+	}
 }
 
 func TestResolveAccount_AppIDAndUserTokenWithoutSecret(t *testing.T) {
@@ -75,18 +92,81 @@ func TestResolveAccount_OnlySecretSet(t *testing.T) {
 	if !errors.As(err, &blockErr) {
 		t.Fatalf("expected BlockError, got %v", err)
 	}
+	if blockErr.Code != credential.BlockReasonCredentialIncomplete ||
+		!slices.Equal(blockErr.MissingKeys, []string{envvars.CliAppID}) ||
+		!slices.Equal(blockErr.PresentKeys, []string{envvars.CliAppSecret}) {
+		t.Fatalf("BlockError = %+v, want incomplete with missing APP_ID and present APP_SECRET", blockErr)
+	}
+	if len(blockErr.RequiredAnyOf) != 0 {
+		t.Fatalf("RequiredAnyOf = %v, want empty for APP_SECRET-only", blockErr.RequiredAnyOf)
+	}
 }
 
 func TestResolveAccount_OnlyTokenSetWithoutAppID(t *testing.T) {
-	t.Setenv(envvars.CliUserAccessToken, "uat_test")
+	for _, tt := range []struct {
+		name string
+		key  string
+	}{
+		{name: "UAT", key: envvars.CliUserAccessToken},
+		{name: "TAT", key: envvars.CliTenantAccessToken},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv(envvars.CliAppID, "")
+			t.Setenv(envvars.CliAppSecret, "")
+			t.Setenv(envvars.CliUserAccessToken, "")
+			t.Setenv(envvars.CliTenantAccessToken, "")
+			t.Setenv(tt.key, "token_test")
 
-	_, err := (&Provider{}).ResolveAccount(context.Background())
-	var blockErr *credential.BlockError
-	if !errors.As(err, &blockErr) {
-		t.Fatalf("expected BlockError, got %v", err)
+			_, err := (&Provider{}).ResolveAccount(context.Background())
+			var blockErr *credential.BlockError
+			if !errors.As(err, &blockErr) {
+				t.Fatalf("expected BlockError, got %v", err)
+			}
+			if !strings.Contains(err.Error(), envvars.CliAppID) {
+				t.Fatalf("error = %v, want mention of %s", err, envvars.CliAppID)
+			}
+			if blockErr.Code != credential.BlockReasonCredentialIncomplete ||
+				!slices.Equal(blockErr.MissingKeys, []string{envvars.CliAppID}) ||
+				!slices.Equal(blockErr.PresentKeys, []string{tt.key}) {
+				t.Fatalf("BlockError = %+v, want incomplete for %s", blockErr, tt.key)
+			}
+			if len(blockErr.RequiredAnyOf) != 0 {
+				t.Fatalf("RequiredAnyOf = %v, want empty for %s-only", blockErr.RequiredAnyOf, tt.name)
+			}
+		})
 	}
-	if !strings.Contains(err.Error(), envvars.CliAppID) {
-		t.Fatalf("error = %v, want mention of %s", err, envvars.CliAppID)
+}
+
+func TestResolveAccount_InvalidPolicyRejectedBeforeIncomplete(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		key  string
+	}{
+		{name: "DEFAULT_AS", key: envvars.CliDefaultAs},
+		{name: "STRICT_MODE", key: envvars.CliStrictMode},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv(envvars.CliAppID, "cli_test")
+			t.Setenv(envvars.CliAppSecret, "")
+			t.Setenv(envvars.CliUserAccessToken, "")
+			t.Setenv(envvars.CliTenantAccessToken, "")
+			t.Setenv(tt.key, "banana")
+
+			_, err := (&Provider{}).ResolveAccount(context.Background())
+			var blockErr *credential.BlockError
+			if !errors.As(err, &blockErr) {
+				t.Fatalf("error = %T %v, want BlockError", err, err)
+			}
+			if blockErr.Code != credential.BlockReasonInvalidPolicy {
+				t.Fatalf("Code = %q, want %q", blockErr.Code, credential.BlockReasonInvalidPolicy)
+			}
+			if blockErr.Param != tt.key {
+				t.Fatalf("Param = %q, want %q", blockErr.Param, tt.key)
+			}
+			if !strings.Contains(blockErr.Reason, tt.key) {
+				t.Fatalf("reason = %q, want %s", blockErr.Reason, tt.key)
+			}
+		})
 	}
 }
 
@@ -258,6 +338,9 @@ func TestResolveAccount_InvalidStrictModeRejected(t *testing.T) {
 	if !errors.As(err, &blockErr) {
 		t.Fatalf("expected BlockError, got %T", err)
 	}
+	if blockErr.Code != credential.BlockReasonInvalidPolicy || blockErr.Param != envvars.CliStrictMode {
+		t.Fatalf("BlockError = %+v, want invalid_policy with Param %s", blockErr, envvars.CliStrictMode)
+	}
 	if !strings.Contains(err.Error(), envvars.CliStrictMode) {
 		t.Fatalf("error = %v, want mention of %s", err, envvars.CliStrictMode)
 	}
@@ -276,6 +359,9 @@ func TestResolveAccount_InvalidDefaultAsRejected(t *testing.T) {
 	if !errors.As(err, &blockErr) {
 		t.Fatalf("expected BlockError, got %T", err)
 	}
+	if blockErr.Code != credential.BlockReasonInvalidPolicy || blockErr.Param != envvars.CliDefaultAs {
+		t.Fatalf("BlockError = %+v, want invalid_policy with Param %s", blockErr, envvars.CliDefaultAs)
+	}
 	if !strings.Contains(err.Error(), envvars.CliDefaultAs) {
 		t.Fatalf("error = %v, want mention of %s", err, envvars.CliDefaultAs)
 	}
diff --git a/extension/credential/sidecar/provider.go b/extension/credential/sidecar/provider.go
index d01f56616b..1ca31ccc1c 100644
--- a/extension/credential/sidecar/provider.go
+++ b/extension/credential/sidecar/provider.go
@@ -77,6 +77,8 @@ func (p *Provider) ResolveAccount(ctx context.Context) (*credential.Account, err
 		return nil, &credential.BlockError{
 			Provider: "sidecar",
 			Reason:   fmt.Sprintf("invalid %s %q (want user, bot, or auto)", envvars.CliDefaultAs, id),
+			Code:     credential.BlockReasonInvalidPolicy,
+			Param:    envvars.CliDefaultAs,
 		}
 	}
 
@@ -92,6 +94,8 @@ func (p *Provider) ResolveAccount(ctx context.Context) (*credential.Account, err
 		return nil, &credential.BlockError{
 			Provider: "sidecar",
 			Reason:   fmt.Sprintf("invalid %s %q (want bot, user, or off)", envvars.CliStrictMode, strictMode),
+			Code:     credential.BlockReasonInvalidPolicy,
+			Param:    envvars.CliStrictMode,
 		}
 	}
 
diff --git a/extension/credential/sidecar/provider_test.go b/extension/credential/sidecar/provider_test.go
index e265b5652f..8873c12050 100644
--- a/extension/credential/sidecar/provider_test.go
+++ b/extension/credential/sidecar/provider_test.go
@@ -7,7 +7,9 @@ package sidecar
 
 import (
 	"context"
+	"errors"
 	"os"
+	"strings"
 	"testing"
 
 	"github.com/larksuite/cli/extension/credential"
@@ -146,6 +148,57 @@ func TestResolveAccount_StrictMode(t *testing.T) {
 	}
 }
 
+func TestResolveAccount_InvalidPolicyClassified(t *testing.T) {
+	setEnv(t, envvars.CliAuthProxy, "http://127.0.0.1:16384")
+	setEnv(t, envvars.CliProxyKey, "test-key")
+	setEnv(t, envvars.CliAppID, "cli_test")
+
+	tests := []struct {
+		name          string
+		key           string
+		value         string
+		supportedText string
+	}{
+		{
+			name:          "default as",
+			key:           envvars.CliDefaultAs,
+			value:         "banana",
+			supportedText: "want user, bot, or auto",
+		},
+		{
+			name:          "strict mode",
+			key:           envvars.CliStrictMode,
+			value:         "banana",
+			supportedText: "want bot, user, or off",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			unsetEnv(t, envvars.CliDefaultAs)
+			unsetEnv(t, envvars.CliStrictMode)
+			setEnv(t, tt.key, tt.value)
+
+			_, err := (&Provider{}).ResolveAccount(context.Background())
+			var blockErr *credential.BlockError
+			if !errors.As(err, &blockErr) {
+				t.Fatalf("error = %T %v, want BlockError", err, err)
+			}
+			if blockErr.Code != credential.BlockReasonInvalidPolicy {
+				t.Fatalf("Code = %q, want %q", blockErr.Code, credential.BlockReasonInvalidPolicy)
+			}
+			if blockErr.Param != tt.key {
+				t.Fatalf("Param = %q, want %q", blockErr.Param, tt.key)
+			}
+			if !strings.Contains(blockErr.Reason, tt.key) ||
+				!strings.Contains(blockErr.Reason, tt.value) ||
+				!strings.Contains(blockErr.Reason, tt.supportedText) {
+				t.Fatalf("Reason = %q, want variable, invalid value, and supported values", blockErr.Reason)
+			}
+		})
+	}
+}
+
 func TestResolveToken_NotActive(t *testing.T) {
 	unsetEnv(t, envvars.CliAuthProxy)
 
diff --git a/extension/credential/types.go b/extension/credential/types.go
index 209013fda5..4c90e2227f 100644
--- a/extension/credential/types.go
+++ b/extension/credential/types.go
@@ -44,6 +44,27 @@ func (s IdentitySupport) UserOnly() bool { return s == SupportsUser }
 // BotOnly returns true if only bot identity is supported.
 func (s IdentitySupport) BotOnly() bool { return s == SupportsBot }
 
+// AccountKind declares how an account participates in credential arbitration.
+type AccountKind int
+
+const (
+	// AccountManaged means the provider owns the whole identity; winning it
+	// ends arbitration outright. The zero value, so existing providers are
+	// unchanged.
+	AccountManaged AccountKind = iota
+	// AccountDirect marks an actively supplied raw credential (the env
+	// provider's LARKSUITE_CLI_* variables). It participates in profile
+	// arbitration and conflict detection instead of winning outright.
+	//
+	// RESERVED: only the builtin env provider may declare AccountDirect
+	// today — the arbitration's direct-credential diagnostics are defined in
+	// terms of the process environment, and the caller rejects AccountDirect
+	// from any other provider. Third-party providers must return
+	// AccountManaged until the SPI carries provider-reported input
+	// descriptors.
+	AccountDirect
+)
+
 // Account holds resolved app credentials and configuration.
 type Account struct {
 	AppID               string
@@ -53,6 +74,7 @@ type Account struct {
 	ProfileName         string
 	OpenID              string          // optional; if UAT is available, API result takes precedence
 	SupportedIdentities IdentitySupport // zero = provider did not declare; treat as no restriction
+	Kind                AccountKind     // AccountManaged (default) or AccountDirect
 }
 
 // Token holds a resolved access token and optional metadata.
@@ -76,11 +98,38 @@ type TokenSpec struct {
 	AppID string
 }
 
+// BlockReason classifies provider-originated block conditions that callers may
+// safely map to a more specific public error contract.
+type BlockReason string
+
+const (
+	// BlockReasonCredentialIncomplete marks incomplete inputs from the builtin
+	// process-env credential provider. It is reserved for that provider because
+	// direct-credential arbitration and diagnostics currently name the fixed
+	// LARKSUITE_CLI_* env surface. Third-party providers must return an
+	// unclassified BlockError until the SPI carries provider-owned input
+	// descriptors. Blocks without a Code propagate unchanged.
+	BlockReasonCredentialIncomplete BlockReason = "credential_incomplete"
+
+	// BlockReasonInvalidPolicy marks a user-supplied policy input (e.g.
+	// LARKSUITE_CLI_DEFAULT_AS / LARKSUITE_CLI_STRICT_MODE) that failed
+	// validation. The caller maps it to a typed validation error carrying
+	// Param and a repair hint, so user input mistakes never surface as
+	// internal errors.
+	BlockReasonInvalidPolicy BlockReason = "invalid_policy"
+)
+
 // BlockError is returned by a Provider to actively reject a request
 // and prevent subsequent providers in the chain from being consulted.
 type BlockError struct {
-	Provider string
-	Reason   string
+	Provider      string
+	Reason        string
+	Code          BlockReason
+	MissingKeys   []string // environment variable names only; never values
+	RequiredAnyOf []string // environment variable names only; never values
+	PresentKeys   []string // environment variable names only; never values
+	AppID         string   // plaintext app identifier used only for source comparison; never a secret
+	Param         string   // name of the invalid input variable on invalid_policy blocks; never a value
 }
 
 func (e *BlockError) Error() string {
diff --git a/internal/client/client_test.go b/internal/client/client_test.go
index 97018078d0..8ccc4b796a 100644
--- a/internal/client/client_test.go
+++ b/internal/client/client_test.go
@@ -48,6 +48,18 @@ func (s *staticTokenResolver) ResolveToken(_ context.Context, _ credential.Token
 	return &credential.TokenResult{Token: "test-token"}, nil
 }
 
+type clientTestAccountResolver struct {
+	appID string
+}
+
+func (r clientTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID, Brand: core.BrandFeishu}, nil
+}
+
+func newClientTestCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, clientTestAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 // newTestAPIClient creates an APIClient with a mock HTTP transport.
 func newTestAPIClient(t *testing.T, rt http.RoundTripper) (*APIClient, *bytes.Buffer) {
 	t.Helper()
@@ -58,7 +70,7 @@ func newTestAPIClient(t *testing.T, rt http.RoundTripper) (*APIClient, *bytes.Bu
 		lark.WithLogLevel(larkcore.LogLevelError),
 		lark.WithHttpClient(httpClient),
 	)
-	testCred := credential.NewCredentialProvider(nil, nil, &staticTokenResolver{}, nil)
+	testCred := newClientTestCredentialProvider("test-app", &staticTokenResolver{})
 	cfg := &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu}
 	return &APIClient{
 		SDK:        sdk,
@@ -463,7 +475,7 @@ func TestDoStream_IgnoresBaseHTTPClientTimeout(t *testing.T) {
 
 	ac := &APIClient{
 		HTTP:       &http.Client{Timeout: 5 * time.Millisecond},
-		Credential: credential.NewCredentialProvider(nil, nil, &staticTokenResolver{}, nil),
+		Credential: newClientTestCredentialProvider("test-app", &staticTokenResolver{}),
 		Config:     &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu},
 	}
 
@@ -498,7 +510,7 @@ func TestDoStream_TransportFailureSplitsSubtype(t *testing.T) {
 	})
 	ac := &APIClient{
 		HTTP:       &http.Client{Transport: rt},
-		Credential: credential.NewCredentialProvider(nil, nil, &staticTokenResolver{}, nil),
+		Credential: newClientTestCredentialProvider("test-app", &staticTokenResolver{}),
 		Config:     &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu},
 	}
 
@@ -532,7 +544,7 @@ func (f *failingTokenResolver) ResolveToken(_ context.Context, spec credential.T
 func TestResolveAccessToken_NoToken_ReturnsTypedAuthenticationError(t *testing.T) {
 	ac := &APIClient{
 		HTTP:       &http.Client{},
-		Credential: credential.NewCredentialProvider(nil, nil, &failingTokenResolver{}, nil),
+		Credential: newClientTestCredentialProvider("test-app", &failingTokenResolver{}),
 		Config:     &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu},
 	}
 
@@ -572,7 +584,7 @@ func (f *needAuthTokenResolver) ResolveToken(_ context.Context, _ credential.Tok
 func TestResolveAccessToken_NeedAuthorization_SurfacesAsTypedAuthentication(t *testing.T) {
 	ac := &APIClient{
 		HTTP:       &http.Client{},
-		Credential: credential.NewCredentialProvider(nil, nil, &needAuthTokenResolver{userOpenID: "ou_test_user"}, nil),
+		Credential: newClientTestCredentialProvider("test-app", &needAuthTokenResolver{userOpenID: "ou_test_user"}),
 		Config:     &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu},
 	}
 
@@ -612,7 +624,7 @@ func TestResolveAccessToken_NeedAuthorization_SurfacesAsTypedAuthentication(t *t
 func TestDoSDKRequest_AuthFailureSurfacesTypedAuthenticationError(t *testing.T) {
 	ac := &APIClient{
 		HTTP:       &http.Client{},
-		Credential: credential.NewCredentialProvider(nil, nil, &failingTokenResolver{}, nil),
+		Credential: newClientTestCredentialProvider("test-app", &failingTokenResolver{}),
 		Config:     &core.CliConfig{AppID: "test-app", AppSecret: "test-secret", Brand: core.BrandFeishu},
 	}
 
diff --git a/internal/cmdutil/factory.go b/internal/cmdutil/factory.go
index 1b167b7863..c90fa1d4a7 100644
--- a/internal/cmdutil/factory.go
+++ b/internal/cmdutil/factory.go
@@ -27,6 +27,11 @@ import (
 // In tests, replace any field to stub out external dependencies.
 type InvocationContext struct {
 	Profile string
+	// ProfileFromFlag is true when Profile was set via the --profile flag,
+	// and false when it came from the LARKSUITE_CLI_PROFILE env fallback
+	// (or neither was set). Downstream credential resolution uses this to
+	// report the correct profile source.
+	ProfileFromFlag bool
 }
 
 type Factory struct {
diff --git a/internal/cmdutil/factory_default.go b/internal/cmdutil/factory_default.go
index 9527346a7b..5a5a76516a 100644
--- a/internal/cmdutil/factory_default.go
+++ b/internal/cmdutil/factory_default.go
@@ -63,10 +63,11 @@ func NewDefault(streams *IOStreams, inv InvocationContext) *Factory {
 	// Phase 2: Credential (sole data source)
 	// Keychain is read via closure so callers can replace f.Keychain after construction.
 	f.Credential = buildCredentialProvider(credentialDeps{
-		Keychain:   func() keychain.KeychainAccess { return f.Keychain },
-		Profile:    inv.Profile,
-		HttpClient: f.HttpClient,
-		ErrOut:     f.IOStreams.ErrOut,
+		Keychain:        func() keychain.KeychainAccess { return f.Keychain },
+		Profile:         inv.Profile,
+		ProfileFromFlag: inv.ProfileFromFlag,
+		HttpClient:      f.HttpClient,
+		ErrOut:          f.IOStreams.ErrOut,
 	})
 
 	// Phase 3: Runtime config contains resolved account data only.
@@ -174,10 +175,11 @@ func wrapSDKTransport(next http.RoundTripper) http.RoundTripper {
 }
 
 type credentialDeps struct {
-	Keychain   func() keychain.KeychainAccess
-	Profile    string
-	HttpClient func() (*http.Client, error)
-	ErrOut     io.Writer
+	Keychain        func() keychain.KeychainAccess
+	Profile         string
+	ProfileFromFlag bool
+	HttpClient      func() (*http.Client, error)
+	ErrOut          io.Writer
 }
 
 func buildCredentialProvider(deps credentialDeps) *credential.CredentialProvider {
@@ -190,5 +192,13 @@ func buildCredentialProvider(deps credentialDeps) *credential.CredentialProvider
 	// depend on. enrichUserInfo failures are already non-fatal (the
 	// provider clears unverified identity fields), so silencing the
 	// warning is safe.
-	return credential.NewCredentialProvider(providers, defaultAcct, defaultToken, deps.HttpClient)
+	cred := credential.NewCredentialProvider(providers, defaultAcct, defaultToken, deps.HttpClient)
+	if deps.Profile == "" {
+		// No profile selected — don't record a phantom env source.
+		return cred
+	}
+	if deps.ProfileFromFlag {
+		return cred.WithProfileFromFlag(deps.Profile)
+	}
+	return cred.WithProfileFromEnv(deps.Profile)
 }
diff --git a/internal/cmdutil/factory_test.go b/internal/cmdutil/factory_test.go
index 97eed80975..a5f00d7b5f 100644
--- a/internal/cmdutil/factory_test.go
+++ b/internal/cmdutil/factory_test.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/larksuite/cli/errs"
 	extcred "github.com/larksuite/cli/extension/credential"
+	envprovider "github.com/larksuite/cli/extension/credential/env"
 	"github.com/larksuite/cli/internal/core"
 	"github.com/larksuite/cli/internal/credential"
 	"github.com/larksuite/cli/internal/envvars"
@@ -405,6 +406,14 @@ type stubExtProvider struct {
 	err  error
 }
 
+type stubDefaultAccountResolver struct {
+	acct *credential.Account
+}
+
+func (s *stubDefaultAccountResolver) ResolveAccount(_ context.Context) (*credential.Account, error) {
+	return s.acct, nil
+}
+
 func (s *stubExtProvider) Name() string { return s.name }
 func (s *stubExtProvider) ResolveAccount(_ context.Context) (*extcred.Account, error) {
 	return s.acct, s.err
@@ -448,6 +457,86 @@ func TestRequireBuiltinCredentialProvider_AllowsBuiltinProvider(t *testing.T) {
 	}
 }
 
+func TestRequireBuiltinCredentialProvider_AllowsMatchingAppIDOnlyProfile(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	t.Setenv(envvars.CliAppID, "cli_a")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	if err := core.SaveMultiAppConfig(&core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{{
+			Name:      "tenant_a",
+			AppId:     "cli_a",
+			AppSecret: core.PlainSecret("test-secret"),
+			Brand:     core.BrandFeishu,
+		}},
+	}); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	cred := credential.NewCredentialProvider(
+		[]extcred.Provider{&envprovider.Provider{}},
+		&stubDefaultAccountResolver{acct: &credential.Account{AppID: "cli_a", AppSecret: "test-secret"}},
+		nil,
+		nil,
+	).WithProfileFromFlag("tenant_a")
+	f, _, _, _ := TestFactory(t, nil)
+	f.Credential = cred
+
+	if err := f.RequireBuiltinCredentialProvider(context.Background(), "auth"); err != nil {
+		t.Fatalf("matching APP_ID-only profile should use builtin credentials: %v", err)
+	}
+}
+
+// A stale LARKSUITE_CLI_PROFILE (profile that cannot resolve) must not lock
+// the user out of the builtin setup/repair commands this gate guards: the
+// probe falls back to provider engagement and lets the command run.
+func TestRequireBuiltinCredentialProvider_StaleProfileDoesNotLockOut(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir()) // no config -> "ghost" cannot resolve
+
+	stub := &stubExtProvider{name: "env"} // not engaged: returns nil, nil
+	cred := credential.NewCredentialProvider(
+		[]extcred.Provider{stub},
+		&stubDefaultAccountResolver{},
+		nil,
+		nil,
+	).WithProfileFromEnv("ghost")
+	f, _, _, _ := TestFactory(t, nil)
+	f.Credential = cred
+
+	if err := f.RequireBuiltinCredentialProvider(context.Background(), "config"); err != nil {
+		t.Fatalf("stale profile must not lock out builtin auth/config commands: %v", err)
+	}
+}
+
+// An invalid policy variable (e.g. LARKSUITE_CLI_DEFAULT_AS=banana) is a user
+// input error, not an external credential takeover: the gate surfaces the
+// same typed validation error as formal arbitration instead of a misleading
+// "provided externally" refusal.
+func TestRequireBuiltinCredentialProvider_InvalidPolicySurfacesTypedError(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+
+	stub := &stubExtProvider{name: "env", err: &extcred.BlockError{
+		Provider: "env",
+		Reason:   "invalid LARKSUITE_CLI_DEFAULT_AS \"banana\" (want user, bot, or auto)",
+		Code:     extcred.BlockReasonInvalidPolicy,
+		Param:    envvars.CliDefaultAs,
+	}}
+	cred := credential.NewCredentialProvider([]extcred.Provider{stub}, &stubDefaultAccountResolver{}, nil, nil)
+	f, _, _, _ := TestFactory(t, nil)
+	f.Credential = cred
+
+	err := f.RequireBuiltinCredentialProvider(context.Background(), "auth")
+	prob, ok := errs.ProblemOf(err)
+	if !ok || prob.Subtype != errs.SubtypeInvalidArgument {
+		t.Fatalf("err = %v, want typed invalid_argument (same as formal arbitration)", err)
+	}
+	if strings.Contains(err.Error(), "provided externally") {
+		t.Fatalf("err = %v, must not read as external takeover", err)
+	}
+}
+
 func TestRequireBuiltinCredentialProvider_NilCredential(t *testing.T) {
 	f, _, _, _ := TestFactory(t, nil)
 	f.Credential = nil
diff --git a/internal/core/config.go b/internal/core/config.go
index 9a96065938..2d4817473f 100644
--- a/internal/core/config.go
+++ b/internal/core/config.go
@@ -255,7 +255,11 @@ func ResolveConfigFromMulti(raw *MultiAppConfig, kc keychain.KeychainAccess, pro
 	}
 
 	if err := ValidateSecretKeyMatch(app.AppId, app.AppSecret); err != nil {
-		return nil, errs.NewConfigError(errs.SubtypeNotConfigured, "appId and appSecret keychain key are out of sync").
+		// invalid_config, not not_configured: the config exists but is
+		// internally inconsistent. not_configured would let callers degrade
+		// this into a generic "secret invalid" answer and destroy the precise
+		// repair hint (which names the expected keychain key — never a value).
+		return nil, errs.NewConfigError(errs.SubtypeInvalidConfig, "appId and appSecret keychain key are out of sync").
 			WithHint("%s", err.Error()).
 			WithCause(err)
 	}
diff --git a/internal/core/notconfigured.go b/internal/core/notconfigured.go
index 068ea86cfa..5ac3ee3bd6 100644
--- a/internal/core/notconfigured.go
+++ b/internal/core/notconfigured.go
@@ -36,16 +36,13 @@ func LoadOrNotConfigured() (*MultiAppConfig, error) {
 		if errors.Is(err, os.ErrNotExist) {
 			return nil, NotConfiguredError()
 		}
-		// Surface the real cause (parse error, permission denied, etc.)
-		// so the user can fix the broken file. A malformed file is
-		// invalid_config; anything else (permission denied, etc.) is
-		// not_configured. Both stay on the typed structured-envelope path
-		// at the root command's error sink.
-		subtype := errs.SubtypeNotConfigured
-		if isMalformedConfigError(err) {
-			subtype = errs.SubtypeInvalidConfig
-		}
-		return nil, errs.NewConfigError(subtype, "failed to load config: %v", err).WithCause(err)
+		// Surface the real cause so the user can fix the broken file. Every
+		// non-ENOENT load failure — malformed JSON, permission denied, I/O
+		// error — means a config EXISTS but cannot be used: invalid_config.
+		// Only a genuinely absent config is not_configured; anything else
+		// classified as not_configured would let callers degrade it into
+		// profile_not_found / no_active_profile and hide the real cause.
+		return nil, errs.NewConfigError(errs.SubtypeInvalidConfig, "failed to load config: %v", err).WithCause(err)
 	}
 	if multi == nil || len(multi.Apps) == 0 {
 		return nil, NotConfiguredError()
diff --git a/internal/credential/authsidecar_contract_test.go b/internal/credential/authsidecar_contract_test.go
new file mode 100644
index 0000000000..d096b44bc0
--- /dev/null
+++ b/internal/credential/authsidecar_contract_test.go
@@ -0,0 +1,154 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+//go:build authsidecar
+
+package credential_test
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/larksuite/cli/errs"
+	extcred "github.com/larksuite/cli/extension/credential"
+	sidecarprovider "github.com/larksuite/cli/extension/credential/sidecar"
+	"github.com/larksuite/cli/internal/credential"
+	"github.com/larksuite/cli/internal/envvars"
+	"github.com/larksuite/cli/internal/output"
+	"github.com/larksuite/cli/sidecar"
+)
+
+func newRealSidecarCredentialProvider(t *testing.T) *credential.CredentialProvider {
+	t.Helper()
+	t.Setenv(envvars.CliAuthProxy, "http://127.0.0.1:16384")
+	t.Setenv(envvars.CliProxyKey, "test-key")
+	t.Setenv(envvars.CliAppID, "cli_sidecar")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	t.Setenv(envvars.CliDefaultAs, "")
+	t.Setenv(envvars.CliStrictMode, "")
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+
+	return credential.NewCredentialProvider(
+		[]extcred.Provider{&sidecarprovider.Provider{}},
+		nil,
+		nil,
+		nil,
+	)
+}
+
+func TestAuthSidecarInvalidPolicyUsesValidationContract(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		key  string
+	}{
+		{name: "default as", key: envvars.CliDefaultAs},
+		{name: "strict mode", key: envvars.CliStrictMode},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			cp := newRealSidecarCredentialProvider(t)
+			t.Setenv(tt.key, "banana")
+
+			_, err := cp.ResolveAccount(context.Background())
+			problem, ok := errs.ProblemOf(err)
+			if !ok {
+				t.Fatalf("error = %T %v, want typed validation error", err, err)
+			}
+			if problem.Category != errs.CategoryValidation || problem.Subtype != errs.SubtypeInvalidArgument {
+				t.Fatalf("problem = %s/%s, want %s/%s", problem.Category, problem.Subtype, errs.CategoryValidation, errs.SubtypeInvalidArgument)
+			}
+			var validationErr *errs.ValidationError
+			if !errors.As(err, &validationErr) {
+				t.Fatalf("error = %T %v, want ValidationError", err, err)
+			}
+			if validationErr.Param != tt.key {
+				t.Fatalf("param = %q, want %q", validationErr.Param, tt.key)
+			}
+			if got := output.ExitCodeOf(err); got != output.ExitValidation {
+				t.Fatalf("exit code = %d, want %d", got, output.ExitValidation)
+			}
+			if !strings.Contains(problem.Hint, tt.key) {
+				t.Fatalf("hint = %q, want variable name %s", problem.Hint, tt.key)
+			}
+			var blockErr *extcred.BlockError
+			if !errors.As(err, &blockErr) ||
+				blockErr.Code != extcred.BlockReasonInvalidPolicy ||
+				blockErr.Param != tt.key {
+				t.Fatalf("cause = %T %v, want classified BlockError for %s", err, err, tt.key)
+			}
+		})
+	}
+}
+
+func TestAuthSidecarGateProbeUsesValidationContract(t *testing.T) {
+	cp := newRealSidecarCredentialProvider(t)
+	t.Setenv(envvars.CliStrictMode, "banana")
+
+	name, err := cp.ActiveExtensionProviderName(context.Background())
+	if name != "" {
+		t.Fatalf("provider name = %q, want empty on invalid policy", name)
+	}
+	problem, ok := errs.ProblemOf(err)
+	if !ok {
+		t.Fatalf("error = %T %v, want typed validation error", err, err)
+	}
+	var validationErr *errs.ValidationError
+	if !errors.As(err, &validationErr) {
+		t.Fatalf("error = %T %v, want ValidationError", err, err)
+	}
+	if problem.Category != errs.CategoryValidation ||
+		problem.Subtype != errs.SubtypeInvalidArgument ||
+		validationErr.Param != envvars.CliStrictMode {
+		t.Fatalf("problem = %+v param = %q, want validation/invalid_argument param %s", problem, validationErr.Param, envvars.CliStrictMode)
+	}
+}
+
+func TestAuthSidecarTokenHonorsSelectedAppID(t *testing.T) {
+	t.Run("matching app returns sentinel", func(t *testing.T) {
+		cp := newRealSidecarCredentialProvider(t)
+
+		result, err := cp.ResolveToken(context.Background(), credential.TokenSpec{
+			Type:  credential.TokenTypeUAT,
+			AppID: "cli_sidecar",
+		})
+		if err != nil {
+			t.Fatalf("ResolveToken: %v", err)
+		}
+		if result == nil || result.Token != sidecar.SentinelUAT {
+			t.Fatalf("result = %+v, want sidecar UAT sentinel", result)
+		}
+	})
+
+	for _, tt := range []struct {
+		name  string
+		appID string
+	}{
+		{name: "empty app id", appID: ""},
+		{name: "conflicting app id", appID: "cli_other"},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			cp := newRealSidecarCredentialProvider(t)
+
+			result, err := cp.ResolveToken(context.Background(), credential.TokenSpec{
+				Type:  credential.TokenTypeUAT,
+				AppID: tt.appID,
+			})
+			if result != nil {
+				t.Fatalf("result = %+v, want no sidecar sentinel", result)
+			}
+			problem, ok := errs.ProblemOf(err)
+			if !ok {
+				t.Fatalf("error = %T %v, want typed internal error", err, err)
+			}
+			if problem.Category != errs.CategoryInternal || problem.Subtype != errs.SubtypeUnknown {
+				t.Fatalf("problem = %s/%s, want %s/%s", problem.Category, problem.Subtype, errs.CategoryInternal, errs.SubtypeUnknown)
+			}
+			if strings.Contains(err.Error(), sidecar.SentinelUAT) {
+				t.Fatalf("error leaked sidecar sentinel: %v", err)
+			}
+		})
+	}
+}
diff --git a/internal/credential/credential_provider.go b/internal/credential/credential_provider.go
index 8f20be11d9..edb1fe83e0 100644
--- a/internal/credential/credential_provider.go
+++ b/internal/credential/credential_provider.go
@@ -9,11 +9,17 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"os"
+	"slices"
+	"strings"
 	"sync"
 
+	"github.com/larksuite/cli/errs"
 	extcred "github.com/larksuite/cli/extension/credential"
+	envprovider "github.com/larksuite/cli/extension/credential/env"
 	"github.com/larksuite/cli/internal/auth"
 	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/envvars"
 )
 
 // DefaultAccountResolver is implemented by the default account provider.
@@ -136,10 +142,21 @@ type CredentialProvider struct {
 	httpClient   func() (*http.Client, error)
 	warnOut      io.Writer
 
+	// profile is the active profile (from --profile or LARKSUITE_CLI_PROFILE);
+	// profileSrc records which of the two supplied it, for the reported
+	// selection and error attribution.
+	profile    string
+	profileSrc CredentialSourceKind
+
 	accountOnce    sync.Once
 	account        *Account
 	accountErr     error
 	selectedSource credentialSource
+	// selection is the explainable credential-selection result, populated by
+	// doResolveAccount under accountOnce. It never carries a secret.
+	selection IdentitySelection
+
+	enrichOnce sync.Once
 
 	hintOnce sync.Once
 	hint     *IdentityHint
@@ -161,49 +178,521 @@ func (p *CredentialProvider) SetWarnOut(warnOut io.Writer) *CredentialProvider {
 	return p
 }
 
+// WithProfileFromFlag records the --profile flag value as the active profile.
+// It governs credential arbitration and the reported selection source.
+func (p *CredentialProvider) WithProfileFromFlag(profile string) *CredentialProvider {
+	p.profile = profile
+	p.profileSrc = SourceFlagProfile
+	return p
+}
+
+// WithProfileFromEnv records the LARKSUITE_CLI_PROFILE env fallback as the
+// active profile. It governs credential arbitration and the reported
+// selection source.
+func (p *CredentialProvider) WithProfileFromEnv(profile string) *CredentialProvider {
+	p.profile = profile
+	p.profileSrc = SourceEnvProfile
+	return p
+}
+
 // ResolveAccount resolves app credentials. Result is cached after first call.
 // NOTE: Uses sync.Once — only the context from the first call is used for resolution.
 // Subsequent calls return the cached result regardless of their context.
 // This is acceptable for CLI (single invocation per process) but not for long-running servers.
 func (p *CredentialProvider) ResolveAccount(ctx context.Context) (*Account, error) {
+	acct, err := p.resolveAccountSelection(ctx)
+	if err != nil || acct == nil {
+		return acct, err
+	}
+	if _, ok := p.selectedSource.(extensionTokenSource); ok {
+		p.enrichOnce.Do(func() {
+			p.enrichOrClearIdentity(ctx, acct, p.selectedSource)
+		})
+	}
+	return acct, nil
+}
+
+// resolveAccountSelection performs and caches only credential selection. It
+// deliberately does not resolve tokens or user_info, so callers can validate
+// the selected app before any token work begins.
+func (p *CredentialProvider) resolveAccountSelection(ctx context.Context) (*Account, error) {
 	p.accountOnce.Do(func() {
 		p.account, p.accountErr = p.doResolveAccount(ctx)
 	})
 	return p.account, p.accountErr
 }
 
+// doResolveAccount arbitrates the credential/App selection in three phases:
+// gather all arbitration inputs in a single I/O pass, decide the route with a
+// pure function, then execute the remaining I/O for the chosen route.
+//
+// Resolution order (encoded in decideIdentity): a managed extension provider
+// (e.g. sidecar) wins outright; then an explicit profile (--profile /
+// LARKSUITE_CLI_PROFILE) arbitrates against the direct env credential
+// (matching app_id → profile supplies credential and tokens; mismatch → hard
+// conflict; incomplete env without a usable app_id → repair error); then a
+// complete direct env credential; then the config default (currentApp →
+// firstApp).
+//
+// It populates p.selection (never carries a secret) and p.selectedSource on
+// every success path.
 func (p *CredentialProvider) doResolveAccount(ctx context.Context) (*Account, error) {
+	in, err := p.gatherIdentityInputs(ctx)
+	if err != nil {
+		return nil, err
+	}
+	d, err := decideIdentity(in)
+	if err != nil {
+		return nil, err
+	}
+	acct, source, err := p.execute(ctx, d, in)
+	if err != nil {
+		return nil, err
+	}
+	p.selectedSource = source
+	// Assigned only after full success: error paths can never leave a
+	// partial selection behind.
+	p.selection = d.selection
+	return acct, nil
+}
+
+// providerAccount pairs an extension-provider account with its token source.
+type providerAccount struct {
+	acct   *Account
+	source extensionTokenSource
+}
+
+// identityInputs is one invocation's complete arbitration input, gathered in
+// a single pass by gatherIdentityInputs. It is read-only after gathering;
+// decideIdentity consumes it without further I/O.
+type identityInputs struct {
+	profile    string
+	profileSrc CredentialSourceKind
+
+	managed *providerAccount // managed extension account; wins arbitration outright
+	direct  *providerAccount // complete direct env credential
+	// directBlock is a provider's explicit incomplete-direct-credential
+	// classification (BlockError.Code == credential_incomplete). It
+	// participates in profile arbitration instead of failing outright.
+	directBlock *extcred.BlockError
+
+	// directKeys / conflictKeys describe the BUILTIN process-env direct
+	// credential surface (LARKSUITE_CLI_* variable NAMES, never values).
+	// They annotate DirectCredentialEnv and conflict hints; a third-party
+	// AccountDirect provider reports its own inputs via BlockError metadata
+	// (PresentKeys/AppID), not through these.
+	directKeys   []string
+	conflictKeys []string
+
+	config    *core.MultiAppConfig
+	configErr error
+}
+
+// gatherIdentityInputs performs the arbitration's read phase: it consults the
+// extension providers and snapshots the config. Providers classify their own
+// failures at the source (BlockError.Code); this layer must not infer them by
+// re-reading environment variables or parsing Reason.
+func (p *CredentialProvider) gatherIdentityInputs(ctx context.Context) (identityInputs, error) {
+	in := identityInputs{
+		profile:      p.profile,
+		profileSrc:   p.profileSrc,
+		directKeys:   presentDirectCredentialKeys(),
+		conflictKeys: presentDirectCredentialInputKeys(),
+	}
 	for _, prov := range p.providers {
 		acct, err := prov.ResolveAccount(ctx)
 		if err != nil {
-			return nil, err
-		}
-		if acct != nil {
-			internal := convertAccount(acct)
-			source := extensionTokenSource{provider: prov}
-			if err := p.enrichUserInfo(ctx, internal, source); err != nil {
-				if p.warnOut != nil {
-					_, _ = fmt.Fprintf(p.warnOut, "warning: unable to verify user identity from credential source %q: %v\n", source.Name(), err)
+			var blockErr *extcred.BlockError
+			if errors.As(err, &blockErr) {
+				switch blockErr.Code {
+				case extcred.BlockReasonCredentialIncomplete:
+					// app_credential_incomplete, profile matching, and
+					// DirectCredentialEnv diagnostics are defined in terms of
+					// the builtin LARKSUITE_CLI_* env surface. Until the SPI
+					// carries provider-owned input descriptors, accepting this
+					// classification from another provider would produce
+					// contradictory arbitration and repair hints.
+					if _, builtin := prov.(*envprovider.Provider); !builtin {
+						return in, newCredentialIncompleteProviderContractError(prov)
+					}
+					in.directBlock = blockErr
+				case extcred.BlockReasonInvalidPolicy:
+					// A user-supplied policy value failed validation; that is
+					// a validation error, never an internal one.
+					return in, newInvalidPolicyError(blockErr)
+				default:
+					// Blocks without a recognized Code preserve their
+					// original attribution.
+					return in, err
 				}
-				// enrichUserInfo failure is non-fatal: SupportedIdentities
-				// (used for strict mode) is already set by the provider.
-				// Clear unverified user identity for safety.
-				internal.UserOpenId = ""
-				internal.UserName = ""
+				break
 			}
-			p.selectedSource = source
-			return internal, nil
+			// Any other provider error preserves its original attribution.
+			return in, err
 		}
+		if acct == nil {
+			continue
+		}
+		pa := &providerAccount{acct: convertAccount(acct), source: extensionTokenSource{provider: prov}}
+		switch acct.Kind {
+		case extcred.AccountDirect:
+			// The arbitration's direct-credential surface — DirectCredentialEnv,
+			// the env:LARKSUITE_CLI_APP_ID selection source, conflict-hint
+			// keys — is defined in terms of the builtin process-env variables.
+			// Until the SPI carries provider-reported input descriptors, only
+			// the builtin env provider may declare AccountDirect; accepting it
+			// from anyone else would produce self-contradictory diagnostics
+			// (e.g. credentialSource "env:LARKSUITE_CLI_APP_ID" with
+			// directCredentialEnv.present=false). The check is by concrete
+			// type: the registry reserves neither names nor uniqueness, so a
+			// Name() comparison would be forgeable.
+			if _, builtin := prov.(*envprovider.Provider); !builtin {
+				return in, errs.NewInternalError(errs.SubtypeUnknown,
+					"credential provider %q declared AccountDirect, which is reserved for the builtin env provider", prov.Name())
+			}
+			in.direct = pa
+		case extcred.AccountManaged:
+			in.managed = pa
+		default:
+			return in, errs.NewInternalError(errs.SubtypeUnknown,
+				"credential provider %q returned unknown AccountKind %d", prov.Name(), acct.Kind)
+		}
+		break // the first engaged provider ends the scan (registry priority order)
+	}
+	// The config snapshot backs profile lookup, the config-default route, and
+	// config-default failure attribution. A winning managed or direct-env
+	// identity without a profile never needs it — and managed identities must
+	// keep working when the config is absent or malformed.
+	if in.managed == nil && (in.profile != "" || in.direct == nil) {
+		in.config, in.configErr = core.LoadOrNotConfigured()
+	}
+	return in, nil
+}
+
+// credentialRoute names which source serves the selected account and tokens.
+type credentialRoute int
+
+const (
+	routeManaged credentialRoute = iota
+	routeProfile
+	routeDirectEnv
+	routeConfigDefault
+)
+
+// decision is decideIdentity's complete verdict. Nothing in it touched I/O.
+type decision struct {
+	route     credentialRoute
+	selection IdentitySelection
+	// profileAppID is set on routeProfile; app_id is plaintext and safe to
+	// echo in the secret-invalid error.
+	profileAppID string
+}
+
+// decideIdentity holds every selection rule in one place: precedence
+// (managed > profile > direct env > config default), profile/direct-env
+// conflict detection, and error attribution. It is pure — same inputs, same
+// verdict — so the full selection matrix is table-testable without env vars
+// or config fixtures.
+func decideIdentity(in identityInputs) (decision, error) {
+	// DirectCredentialEnv reports the direct env vars truthfully on every
+	// route: Present always means "direct credential env vars are set".
+	directEnv := DirectCredentialEnv{Present: len(in.directKeys) > 0, Keys: in.directKeys}
+	if in.direct != nil {
+		directEnv.AppID = in.direct.acct.AppID
+	}
+	switch {
+	case in.managed != nil:
+		return decision{route: routeManaged, selection: IdentitySelection{
+			Source:              SourceExtension(in.managed.source.Name()),
+			DirectCredentialEnv: directEnv,
+		}}, nil
+	case in.profile != "":
+		return decideProfile(in, directEnv)
+	case in.directBlock != nil:
+		return decision{}, newAppCredentialIncompleteError(in.directBlock, false)
+	case in.direct != nil:
+		return decision{route: routeDirectEnv, selection: IdentitySelection{
+			Source:              SourceEnvAppID,
+			DirectCredentialEnv: directEnv,
+		}}, nil
+	default:
+		return decision{route: routeConfigDefault, selection: IdentitySelection{
+			Source:              selectionSourceForDefault(in.config),
+			DirectCredentialEnv: directEnv,
+		}}, nil
 	}
-	if p.defaultAcct != nil {
+}
+
+// decideProfile arbitrates an explicit profile against the direct env
+// credential state.
+func decideProfile(in identityInputs, directEnv DirectCredentialEnv) (decision, error) {
+	app, err := findProfile(in)
+	if err != nil {
+		return decision{}, err
+	}
+	if in.directBlock != nil {
+		// APP_ID-only is sufficient to compare sources: a matching selected
+		// profile supplies the credential and tokens; a mismatch is the same
+		// hard conflict as a complete direct env. Anything less than a usable
+		// app_id keeps the provider's repair error, extended with the
+		// unset-to-use-the-profile path.
+		if in.directBlock.AppID == "" || !slices.Contains(in.directBlock.PresentKeys, envvars.CliAppID) {
+			return decision{}, newAppCredentialIncompleteError(in.directBlock, true)
+		}
+		if app.AppId != in.directBlock.AppID {
+			return decision{}, newProfileAppCredentialConflict(
+				in.profile, app.AppId, in.directBlock.AppID, in.directBlock.PresentKeys)
+		}
+		directEnv.AppID = in.directBlock.AppID
+		directEnv.Matched = true
+	}
+	if in.direct != nil {
+		// E == complete: the direct env app_id must match the profile.
+		if app.AppId != in.direct.acct.AppID {
+			return decision{}, newProfileAppCredentialConflict(
+				in.profile, app.AppId, in.direct.acct.AppID, in.conflictKeys)
+		}
+		directEnv.Matched = true
+	}
+	return decision{
+		route:        routeProfile,
+		selection:    IdentitySelection{Source: in.profileSrc, DirectCredentialEnv: directEnv},
+		profileAppID: app.AppId,
+	}, nil
+}
+
+// findProfile resolves the requested profile against the config snapshot.
+// A malformed config must surface its real typed cause (invalid_config):
+// reporting it as profile_not_found would send the user to `profile list`
+// and hide the broken file. Only a genuinely absent config degrades to
+// profile_not_found, because the profile then cannot exist anywhere. Both
+// deliberately outrank an incomplete direct env: fixing the profile side is
+// what makes the selected profile usable.
+func findProfile(in identityInputs) (*core.AppConfig, error) {
+	if in.configErr != nil {
+		if prob, ok := errs.ProblemOf(in.configErr); !ok || prob.Subtype != errs.SubtypeNotConfigured {
+			return nil, in.configErr
+		}
+	}
+	if in.config != nil {
+		if app := in.config.FindApp(in.profile); app != nil {
+			return app, nil
+		}
+	}
+	return nil, errs.NewConfigError(errs.SubtypeProfileNotFound,
+		"profile %q not found", in.profile).
+		WithProfile(in.profile).
+		WithCredentialSource(string(in.profileSrc)).
+		WithHint("run `lark-cli profile list` to see available profiles.")
+}
+
+// execute performs the remaining I/O for the decided route and returns the
+// account together with its token source.
+func (p *CredentialProvider) execute(ctx context.Context, d decision, in identityInputs) (*Account, credentialSource, error) {
+	switch d.route {
+	case routeManaged:
+		return in.managed.acct, in.managed.source, nil
+	case routeDirectEnv:
+		return in.direct.acct, in.direct.source, nil
+	case routeProfile:
+		// Resolve the profile's own (keychain-backed) credential locally.
 		acct, err := p.defaultAcct.ResolveAccount(ctx)
 		if err != nil {
-			return nil, err
+			// A typed failure other than not_configured carries its own
+			// precise, secret-free diagnosis (typed errors never embed secret
+			// material per the error contract) — pass it through instead of
+			// flattening it into the generic secret error. Untyped failures
+			// and a config that vanished mid-resolution stay masked: their
+			// content is not guaranteed secret-free.
+			if prob, ok := errs.ProblemOf(err); ok && prob.Subtype != errs.SubtypeNotConfigured {
+				return nil, nil, err
+			}
+			return nil, nil, newProfileSecretInvalidError(in.profile, d.profileAppID)
 		}
-		p.selectedSource = defaultTokenSource{resolver: p.defaultToken}
-		return acct, nil
+		// The resolver re-reads the config; a concurrent profile edit between
+		// gather and here could hand back a different app. Refuse the mismatch
+		// instead of silently using credentials the arbitration never checked.
+		if acct.AppID != d.profileAppID {
+			return nil, nil, errs.NewInternalError(errs.SubtypeUnknown,
+				"config changed during resolution: profile %q resolved to a different app", in.profile).
+				WithHint("retry the command.")
+		}
+		return acct, defaultTokenSource{resolver: p.defaultToken}, nil
+	default: // routeConfigDefault
+		if p.defaultAcct == nil {
+			return nil, nil, core.NotConfiguredError()
+		}
+		acct, err := p.defaultAcct.ResolveAccount(ctx)
+		if err != nil {
+			return nil, nil, translateConfigDefaultFailure(err, in.config)
+		}
+		return acct, defaultTokenSource{resolver: p.defaultToken}, nil
+	}
+}
+
+// translateConfigDefaultFailure attributes a config-default failure from the
+// snapshot: a default profile that EXISTS (has an app_id) but whose secret
+// cannot be resolved locally is profile_secret_invalid — "identity is
+// configured, its secret is broken" is more actionable than "no active
+// profile". Only when there is genuinely no usable default profile do we
+// report no_active_profile. Other typed failures pass through unchanged.
+func translateConfigDefaultFailure(err error, multi *core.MultiAppConfig) error {
+	if prob, ok := errs.ProblemOf(err); !ok || prob.Subtype != errs.SubtypeNotConfigured {
+		return err
+	}
+	if multi != nil {
+		if app := multi.CurrentAppConfig(""); app != nil && app.AppId != "" {
+			return newProfileSecretInvalidError(app.ProfileName(), app.AppId)
+		}
+	}
+	return errs.NewConfigError(errs.SubtypeNoActiveProfile, "no active profile").
+		WithCredentialSource(noActiveProfileCredentialSource).
+		WithHint("run `lark-cli config init` / `lark-cli profile add`, or set %s.", envvars.CliProfile)
+}
+
+func newProfileAppCredentialConflict(profile, profileAppID, envAppID string, presentKeys []string) error {
+	err := errs.NewValidationError(errs.SubtypeProfileAppCredentialConflict,
+		"profile %q app_id does not match %s", profile, envvars.CliAppID).
+		WithProfileAppConflict(profileAppID, envAppID)
+	if len(presentKeys) > 0 {
+		return err.WithHint("unset %s, or select a profile whose app_id matches the environment.",
+			humanList(presentKeys, "and"))
+	}
+	return err.WithHint("unset the direct credential environment variables, or select a profile whose app_id matches the environment.")
+}
+
+func newAppCredentialIncompleteError(blockErr *extcred.BlockError, selectedProfileAvailable bool) *errs.ConfigError {
+	err := errs.NewConfigError(errs.SubtypeAppCredentialIncomplete, "%s", blockErr.Reason).
+		WithCause(blockErr)
+	if len(blockErr.MissingKeys) > 0 {
+		err.WithMissingKeys(blockErr.MissingKeys...)
+	}
+	if len(blockErr.RequiredAnyOf) > 0 {
+		err.WithRequiredAnyOf(blockErr.RequiredAnyOf...)
+	}
+
+	hint := credentialRepairHint(blockErr)
+	if selectedProfileAvailable && len(blockErr.PresentKeys) > 0 {
+		hint += fmt.Sprintf(", or unset %s to use the selected profile", humanList(blockErr.PresentKeys, "and"))
+	}
+	return err.WithHint("%s.", hint)
+}
+
+func credentialRepairHint(blockErr *extcred.BlockError) string {
+	if len(blockErr.RequiredAnyOf) > 0 {
+		return "set " + humanList(blockErr.RequiredAnyOf, "or")
+	}
+	return "set " + humanList(blockErr.MissingKeys, "and")
+}
+
+func humanList(items []string, conjunction string) string {
+	switch len(items) {
+	case 0:
+		return "the missing direct credential variables"
+	case 1:
+		return items[0]
+	case 2:
+		return items[0] + " " + conjunction + " " + items[1]
+	default:
+		return strings.Join(items[:len(items)-1], ", ") + ", " + conjunction + " " + items[len(items)-1]
+	}
+}
+
+// newInvalidPolicyError translates a provider's invalid-policy block into the
+// typed validation contract: the failed variable name travels in param, the
+// repair path in the hint, and the original block stays on the cause chain.
+// Reason carries only the variable name and its non-secret value.
+func newInvalidPolicyError(blockErr *extcred.BlockError) error {
+	return errs.NewValidationError(errs.SubtypeInvalidArgument, "%s", blockErr.Reason).
+		WithParam(blockErr.Param).
+		WithCause(blockErr).
+		WithHint("set %s to a supported value or unset it.", blockErr.Param)
+}
+
+func newCredentialIncompleteProviderContractError(prov extcred.Provider) error {
+	return errs.NewInternalError(errs.SubtypeUnknown,
+		"credential provider %q returned credential_incomplete, which is reserved for the builtin env provider", prov.Name())
+}
+
+// newProfileSecretInvalidError is deliberately generic (SECURITY): the
+// underlying cause may carry secret material, so neither it nor its message
+// may reach the envelope. app_id is plaintext and safe to echo.
+func newProfileSecretInvalidError(profile, appID string) error {
+	return errs.NewConfigError(errs.SubtypeProfileSecretInvalid,
+		"profile %q credential could not be resolved locally", profile).
+		WithProfile(profile).
+		WithAppID(appID).
+		WithHint("verify the profile's app secret or re-add the profile with `lark-cli config`.")
+}
+
+// enrichOrClearIdentity verifies a provider-supplied user identity via
+// enrichUserInfo. Verification failure is non-fatal — SupportedIdentities
+// (used for strict mode) is already set by the provider — but an unverified
+// identity must not survive it: a stale OpenID would attribute calls to a
+// user the token can no longer act for.
+func (p *CredentialProvider) enrichOrClearIdentity(ctx context.Context, acct *Account, source credentialSource) {
+	err := p.enrichUserInfo(ctx, acct, source)
+	if err == nil {
+		return
+	}
+	if p.warnOut != nil {
+		_, _ = fmt.Fprintf(p.warnOut, "warning: unable to verify user identity from credential source %q: %v\n", source.Name(), err)
+	}
+	acct.UserOpenId = ""
+	acct.UserName = ""
+}
+
+// noActiveProfileCredentialSource is the credential_source reported on the
+// no_active_profile error. The error contract fixes this to the literal "config": there is
+// no resolved default profile at all, so the more specific config:currentApp /
+// config:firstApp source values (used on successful config-default selections)
+// would be misleading. It is an enum string, never a secret.
+const noActiveProfileCredentialSource = "config"
+
+// selectionSourceForDefault reports whether the config default resolved to the
+// explicit currentApp or fell back to the first app.
+func selectionSourceForDefault(multi *core.MultiAppConfig) CredentialSourceKind {
+	if multi != nil && multi.CurrentApp != "" {
+		return SourceConfigCurrentApp
 	}
-	return nil, core.NotConfiguredError()
+	return SourceConfigFirstApp
+}
+
+// presentDirectCredentialKeys returns the NAMES (never values) of the direct
+// app credential env vars that are set. Used to annotate DirectCredentialEnv.
+func presentDirectCredentialKeys() []string {
+	var keys []string
+	if os.Getenv(envvars.CliAppID) != "" {
+		keys = append(keys, envvars.CliAppID)
+	}
+	if os.Getenv(envvars.CliAppSecret) != "" {
+		keys = append(keys, envvars.CliAppSecret)
+	}
+	return keys
+}
+
+// presentDirectCredentialInputKeys returns all direct env input names that
+// must be cleared together to remove a profile/app_id conflict. Values are
+// never returned.
+func presentDirectCredentialInputKeys() []string {
+	keys := presentDirectCredentialKeys()
+	if os.Getenv(envvars.CliUserAccessToken) != "" {
+		keys = append(keys, envvars.CliUserAccessToken)
+	}
+	if os.Getenv(envvars.CliTenantAccessToken) != "" {
+		keys = append(keys, envvars.CliTenantAccessToken)
+	}
+	return keys
+}
+
+// Selection resolves the account (once) and returns the cached, secret-free
+// explanation of how the credential/App was selected. It mirrors
+// selectedCredentialSource: resolve-then-return.
+func (p *CredentialProvider) Selection(ctx context.Context) (IdentitySelection, error) {
+	if _, err := p.ResolveAccount(ctx); err != nil {
+		return IdentitySelection{}, err
+	}
+	return p.selection, nil
 }
 
 // enrichUserInfo resolves user identity when extension provides a UAT.
@@ -239,17 +728,13 @@ func (p *CredentialProvider) enrichUserInfo(ctx context.Context, acct *Account,
 }
 
 func (p *CredentialProvider) selectedCredentialSource(ctx context.Context) (credentialSource, error) {
-	if p.selectedSource != nil {
-		return p.selectedSource, nil
-	}
-	if p.defaultAcct == nil {
-		return nil, nil
-	}
-	if _, err := p.ResolveAccount(ctx); err != nil {
+	if _, err := p.resolveAccountSelection(ctx); err != nil {
 		return nil, err
 	}
 	if p.selectedSource == nil {
-		return nil, fmt.Errorf("credential provider resolved an account without selecting a token source")
+		return nil, errs.NewInternalError(errs.SubtypeUnknown,
+			"credential provider resolved an account without selecting a token source").
+			WithHint("retry the command.")
 	}
 	return p.selectedSource, nil
 }
@@ -302,51 +787,88 @@ func (p *CredentialProvider) doResolveIdentityHint(ctx context.Context) (*Identi
 
 // ResolveToken resolves an access token.
 func (p *CredentialProvider) ResolveToken(ctx context.Context, req TokenSpec) (*TokenResult, error) {
-	source, err := p.selectedCredentialSource(ctx)
+	acct, err := p.resolveAccountSelection(ctx)
 	if err != nil {
 		return nil, err
 	}
-	if source != nil {
-		return resolveTokenFromSource(ctx, source, req)
+	if acct == nil {
+		return nil, errs.NewInternalError(errs.SubtypeUnknown,
+			"credential provider resolved no account before %s token resolution", req.Type).
+			WithHint("retry the command.")
 	}
-
-	for _, prov := range p.providers {
-		source := extensionTokenSource{provider: prov}
-		result, found, err := source.TryResolveToken(ctx, req)
-		if err != nil {
-			return nil, err
-		}
-		if found {
-			return result, nil
-		}
+	source := p.selectedSource
+	if source == nil {
+		return nil, errs.NewInternalError(errs.SubtypeUnknown,
+			"credential provider resolved app %q without selecting a token source", acct.AppID).
+			WithHint("retry the command.")
 	}
-	source = defaultTokenSource{resolver: p.defaultToken}
-	result, found, err := source.TryResolveToken(ctx, req)
-	if err != nil {
-		return nil, err
+	if req.AppID == "" {
+		return nil, errs.NewInternalError(errs.SubtypeUnknown,
+			"TokenSpec.AppID is required for %s token resolution", req.Type).
+			WithHint("retry the command.")
 	}
-	if found {
-		return result, nil
+	if req.AppID != acct.AppID {
+		return nil, errs.NewInternalError(errs.SubtypeUnknown,
+			"token requested for app %q but the selected account belongs to app %q", req.AppID, acct.AppID).
+			WithHint("retry the command.")
 	}
-	return nil, &TokenUnavailableError{Type: req.Type}
+	return resolveTokenFromSource(ctx, source, req)
 }
 
 // ActiveExtensionProviderName reports whether an extension provider is managing
-// credentials. It probes p.providers (extension providers only, not defaultAcct)
-// and returns the name of the first engaged provider.
+// the credentials that actually win selection. With an explicit profile that
+// resolves successfully it reuses ResolveAccount's cached arbitration result;
+// otherwise it probes extension providers directly and returns the first
+// engaged provider.
 //
 // "Engaged" means: ResolveAccount returns a non-nil account, OR returns a
 // *extcred.BlockError (provider configured but misconfigured — still counts as
-// external). Any other error is propagated to the caller.
+// external). Any other probe error is propagated to the caller.
+//
+// A failed profile resolution (profile not found, broken secret, malformed
+// config, incomplete direct env, ...) deliberately does NOT propagate: this
+// probe guards the builtin setup/repair commands (auth, config), and an
+// unresolvable credential must never lock the user out of the commands that
+// fix it. It falls back to the engagement probe, which answers the only
+// question this function owns: is an extension provider holding credentials?
 //
 // Returns ("", nil) when no extension provider is active (built-in keychain path).
-// Safe to call multiple times — probes providers directly without the sync.Once cache.
+// Safe to call multiple times: explicit-profile resolution uses sync.Once, while
+// the probe path only consults providers.
 func (p *CredentialProvider) ActiveExtensionProviderName(ctx context.Context) (string, error) {
+	// With an explicit profile, report the source that actually won the same
+	// arbitration used by commands. A matching APP_ID-only env block is not an
+	// external takeover once the selected profile supplies credentials/tokens.
+	if p.profile != "" {
+		if _, err := p.ResolveAccount(ctx); err == nil {
+			if p.selectedSource == nil {
+				return "", nil
+			}
+			if _, builtin := p.selectedSource.(defaultTokenSource); builtin {
+				return "", nil
+			}
+			return p.selectedSource.Name(), nil
+		}
+		// Resolution failed — fall through to the engagement probe.
+	}
 	for _, prov := range p.providers {
 		acct, err := prov.ResolveAccount(ctx)
 		if err != nil {
 			var blockErr *extcred.BlockError
 			if errors.As(err, &blockErr) {
+				// Align with formal arbitration: a misconfigured policy
+				// variable is the same typed validation error everywhere —
+				// not an external takeover of the provider that reported it,
+				// and not license to keep scanning and blame a later
+				// provider instead.
+				if blockErr.Code == extcred.BlockReasonInvalidPolicy {
+					return "", newInvalidPolicyError(blockErr)
+				}
+				if blockErr.Code == extcred.BlockReasonCredentialIncomplete {
+					if _, builtin := prov.(*envprovider.Provider); !builtin {
+						return "", newCredentialIncompleteProviderContractError(prov)
+					}
+				}
 				name := blockErr.Provider
 				if name == "" {
 					name = prov.Name()
diff --git a/internal/credential/credential_provider_selection_test.go b/internal/credential/credential_provider_selection_test.go
new file mode 100644
index 0000000000..48641cc7bd
--- /dev/null
+++ b/internal/credential/credential_provider_selection_test.go
@@ -0,0 +1,1124 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package credential_test
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"runtime"
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/larksuite/cli/errs"
+	extcred "github.com/larksuite/cli/extension/credential"
+	envprovider "github.com/larksuite/cli/extension/credential/env"
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/credential"
+	"github.com/larksuite/cli/internal/envvars"
+	"github.com/larksuite/cli/internal/keychain"
+	"github.com/larksuite/cli/internal/output"
+)
+
+func asConfigError(t *testing.T, err error) *errs.ConfigError {
+	t.Helper()
+	var ce *errs.ConfigError
+	if !errors.As(err, &ce) {
+		t.Fatalf("expected *errs.ConfigError, got %T: %v", err, err)
+	}
+	return ce
+}
+
+func asValidationError(t *testing.T, err error) *errs.ValidationError {
+	t.Helper()
+	var ve *errs.ValidationError
+	if !errors.As(err, &ve) {
+		t.Fatalf("expected *errs.ValidationError, got %T: %v", err, err)
+	}
+	return ve
+}
+
+// secretValue is the profile secret written to config. It must NEVER appear in
+// any error message or IdentitySelection (security: never leak a secret).
+const secretValue = "your-secret"
+
+// envSecretValue is the direct env app secret. Same no-leak guarantee.
+const envSecretValue = "your-password"
+
+// writeConfigTenantA writes a config with a single profile "tenant_a" (app_id
+// "cli_a"). The secret is a plaintext secret stored in config, which resolves
+// locally without a keychain lookup.
+func writeConfigTenantA(t *testing.T) {
+	t.Helper()
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	multi := &core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{{
+			Name:      "tenant_a",
+			AppId:     "cli_a",
+			AppSecret: core.PlainSecret(secretValue),
+			Brand:     core.BrandFeishu,
+		}},
+	}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+}
+
+// writeConfigTenantABroken writes tenant_a with a keychain-backed secret ref
+// that cannot be resolved (noop keychain returns empty), so profile secret
+// resolution fails locally.
+func writeConfigTenantABroken(t *testing.T) {
+	t.Helper()
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	// A keychain SecretRef whose key does NOT match app_id cli_a. Local secret
+	// resolution fails (ValidateSecretKeyMatch), exercising profile_secret_invalid.
+	multi := &core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps: []core.AppConfig{{
+			Name:      "tenant_a",
+			AppId:     "cli_a",
+			AppSecret: core.SecretInput{Ref: &core.SecretRef{Source: "keychain", ID: "appsecret:wrong_key"}},
+			Brand:     core.BrandFeishu,
+		}},
+	}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+}
+
+func newProvider(t *testing.T, profile string, fromFlag bool) *credential.CredentialProvider {
+	t.Helper()
+	ep := &envprovider.Provider{}
+	defaultAcct := credential.NewDefaultAccountProvider(func() keychain.KeychainAccess { return &noopKC{} }, profile)
+	cp := credential.NewCredentialProvider([]extcred.Provider{ep}, defaultAcct, nil, nil)
+	if fromFlag {
+		cp.WithProfileFromFlag(profile)
+	} else {
+		cp.WithProfileFromEnv(profile)
+	}
+	return cp
+}
+
+// assertNoSecretLeak fails if any secret value appears in the given strings.
+func assertNoSecretLeak(t *testing.T, where string, vals ...string) {
+	t.Helper()
+	for _, v := range vals {
+		if v == "" {
+			continue
+		}
+		if strings.Contains(v, secretValue) {
+			t.Errorf("%s leaked profile secret: %q", where, v)
+		}
+		if strings.Contains(v, envSecretValue) {
+			t.Errorf("%s leaked env secret: %q", where, v)
+		}
+	}
+}
+
+func subtypeOf(t *testing.T, err error) errs.Subtype {
+	t.Helper()
+	if err == nil {
+		t.Fatalf("expected error, got nil")
+	}
+	p, ok := errs.ProblemOf(err)
+	if !ok {
+		t.Fatalf("error is not a typed problem: %v", err)
+	}
+	return p.Subtype
+}
+
+// With no profile, direct credential, or config default, selection reports no_active_profile.
+func TestSelection_NoActiveProfile(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir()) // empty dir -> no config
+	cp := newProvider(t, "", false)
+
+	sel, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeNoActiveProfile {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeNoActiveProfile)
+	}
+	// no_active_profile must carry credential_source=config.
+	ce := asConfigError(t, err)
+	if ce.CredentialSource != "config" {
+		t.Errorf("credential_source = %q, want %q", ce.CredentialSource, "config")
+	}
+	assertNoSecretLeak(t, "state2", err.Error(), string(sel.Source))
+}
+
+// Config-default profile with an out-of-sync keychain ref: the precise typed
+// cause (invalid_config) passes through on the default route too — parity
+// with main, which surfaced this exact diagnosis before the profile feature.
+func TestSelection_ConfigDefaultKeychainOutOfSyncSurfacesRealCause(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantABroken(t) // CurrentApp = tenant_a (app_id cli_a), out-of-sync keychain ref
+	cp := newProvider(t, "", false)
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeInvalidConfig {
+		t.Fatalf("subtype = %q, want invalid_config (precise cause, not no_active_profile)", got)
+	}
+	prob, _ := errs.ProblemOf(err)
+	if !strings.Contains(prob.Message, "out of sync") {
+		t.Errorf("message = %q, want the out-of-sync diagnosis", prob.Message)
+	}
+	if !strings.Contains(prob.Hint, "appsecret:cli_a") {
+		t.Errorf("hint = %q, want the expected keychain key named", prob.Hint)
+	}
+	assertNoSecretLeak(t, "config-default-out-of-sync", prob.Message, prob.Hint)
+}
+
+// writeMalformedConfig points the config dir at a temp file containing invalid
+// JSON, with no direct-credential env set.
+func writeMalformedConfig(t *testing.T) {
+	t.Helper()
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	if err := os.MkdirAll(core.GetConfigDir(), 0o700); err != nil {
+		t.Fatalf("mkdir config dir: %v", err)
+	}
+	if err := os.WriteFile(core.GetConfigPath(), []byte("{ this is not valid json"), 0o600); err != nil {
+		t.Fatalf("write malformed config: %v", err)
+	}
+}
+
+// assertMalformedSurfaced requires the malformed config to surface as the typed
+// invalid_config subtype — never masked (as profile_not_found on the explicit
+// path, or no_active_profile on the config-default path), which would hide a
+// broken file and misdirect the user (e.g. to `config init`, risking overwrite
+// of a recoverable config).
+func assertMalformedSurfaced(t *testing.T, err error) {
+	t.Helper()
+	if err == nil {
+		t.Fatalf("expected error for malformed config, got nil")
+	}
+	prob, ok := errs.ProblemOf(err)
+	if !ok {
+		t.Fatalf("malformed config error is not typed: %v", err)
+	}
+	if prob.Subtype != errs.SubtypeInvalidConfig {
+		t.Fatalf("malformed config subtype = %q, want invalid_config (not masked)", prob.Subtype)
+	}
+}
+
+// Explicit profile + malformed config → invalid_config, not profile_not_found.
+func TestSelection_ExplicitProfile_MalformedConfig_PropagatesError(t *testing.T) {
+	writeMalformedConfig(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	_, err := cp.Selection(context.Background())
+	assertMalformedSurfaced(t, err)
+}
+
+// Config-default path (no profile) + malformed config → invalid_config, not
+// no_active_profile. Both paths route through core.LoadOrNotConfigured so a
+// temporarily broken config is never misreported as "no active profile, run
+// config init".
+func TestSelection_ConfigDefault_MalformedConfig_PropagatesError(t *testing.T) {
+	writeMalformedConfig(t)
+	cp := newProvider(t, "", false)
+
+	_, err := cp.Selection(context.Background())
+	assertMalformedSurfaced(t, err)
+}
+
+// APP_ID without a secret or access token reports app_credential_incomplete.
+func TestSelection_AppIDOnlyWithoutProfile(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_env")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "", false)
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeAppCredentialIncomplete {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeAppCredentialIncomplete)
+	}
+	if got := output.ExitCodeOf(err); got != output.ExitAuth {
+		t.Fatalf("exit code = %d, want %d", got, output.ExitAuth)
+	}
+	prob, _ := errs.ProblemOf(err)
+	ce := asConfigError(t, err)
+	if len(ce.MissingKeys) != 0 {
+		t.Errorf("missing_keys = %v, want empty because no single key is required", ce.MissingKeys)
+	}
+	wantAnyOf := []string{envvars.CliAppSecret, envvars.CliUserAccessToken, envvars.CliTenantAccessToken}
+	if !slices.Equal(ce.RequiredAnyOf, wantAnyOf) {
+		t.Errorf("required_any_of = %v, want %v", ce.RequiredAnyOf, wantAnyOf)
+	}
+	// required_any_of must be NAMES only, never values.
+	for _, k := range ce.RequiredAnyOf {
+		if strings.Contains(k, envSecretValue) || strings.Contains(k, secretValue) {
+			t.Errorf("required_any_of contains a value, not a name: %q", k)
+		}
+	}
+	wantHint := "set LARKSUITE_CLI_APP_SECRET, LARKSUITE_CLI_USER_ACCESS_TOKEN, or LARKSUITE_CLI_TENANT_ACCESS_TOKEN."
+	if ce.Hint != wantHint {
+		t.Errorf("hint = %q, want %q", ce.Hint, wantHint)
+	}
+	var blockErr *extcred.BlockError
+	if !errors.As(err, &blockErr) || blockErr.Code != extcred.BlockReasonCredentialIncomplete {
+		t.Fatalf("cause chain does not preserve credential BlockError: %T %v", err, err)
+	}
+	assertNoSecretLeak(t, "state3", prob.Message, prob.Hint)
+}
+
+func TestSelection_IncompleteDirectEnvWithoutProfile_UsesDirectRepairOnly(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		key  string
+	}{
+		{name: "APP_SECRET-only", key: envvars.CliAppSecret},
+		{name: "UAT-only", key: envvars.CliUserAccessToken},
+		{name: "TAT-only", key: envvars.CliTenantAccessToken},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv(envvars.CliAppID, "")
+			t.Setenv(envvars.CliAppSecret, "")
+			t.Setenv(envvars.CliUserAccessToken, "")
+			t.Setenv(envvars.CliTenantAccessToken, "")
+			t.Setenv(tt.key, "direct-value")
+			t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+
+			cp := newProvider(t, "", false)
+			_, err := cp.Selection(context.Background())
+			ce := asConfigError(t, err)
+			if got := output.ExitCodeOf(err); got != output.ExitAuth {
+				t.Fatalf("exit code = %d, want %d", got, output.ExitAuth)
+			}
+			if ce.Message != tt.key+" is set but "+envvars.CliAppID+" is missing" {
+				t.Errorf("message = %q, want provider's exact reason", ce.Message)
+			}
+			if ce.Hint != "set "+envvars.CliAppID+"." {
+				t.Errorf("hint = %q, want direct repair only", ce.Hint)
+			}
+			if !slices.Equal(ce.MissingKeys, []string{envvars.CliAppID}) {
+				t.Errorf("missing_keys = %v, want [%s]", ce.MissingKeys, envvars.CliAppID)
+			}
+		})
+	}
+}
+
+// A complete direct credential without a profile is selected from APP_ID env.
+func TestSelection_CompleteDirectEnv(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_env")
+	t.Setenv(envvars.CliAppSecret, envSecretValue)
+	writeConfigTenantA(t)
+	cp := newProvider(t, "", false)
+
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if sel.Source != credential.SourceEnvAppID {
+		t.Fatalf("source = %q, want %q", sel.Source, credential.SourceEnvAppID)
+	}
+	if !sel.DirectCredentialEnv.Present {
+		t.Errorf("DirectCredentialEnv.Present = false, want true")
+	}
+	assertNoSecretLeak(t, "state4", string(sel.Source), sel.DirectCredentialEnv.AppID)
+	assertNoSecretLeak(t, "state4-keys", sel.DirectCredentialEnv.Keys...)
+}
+
+// A valid profile selected by flag reports flag:--profile as its source.
+func TestSelection_ProfileOnlyFromFlag(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if sel.Source != credential.SourceFlagProfile {
+		t.Fatalf("source = %q, want %q", sel.Source, credential.SourceFlagProfile)
+	}
+	if sel.DirectCredentialEnv.Present {
+		t.Errorf("DirectCredentialEnv.Present = true, want false")
+	}
+	assertNoSecretLeak(t, "state5", string(sel.Source))
+}
+
+// A valid profile selected by env reports LARKSUITE_CLI_PROFILE as its source.
+func TestSelection_ProfileOnlyFromEnv(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", false)
+
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if sel.Source != credential.SourceEnvProfile {
+		t.Fatalf("source = %q, want %q", sel.Source, credential.SourceEnvProfile)
+	}
+}
+
+// An explicitly selected missing profile reports profile_not_found even when direct env is complete.
+func TestSelection_MissingProfileWinsOverDirectEnv(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_env")
+	t.Setenv(envvars.CliAppSecret, envSecretValue)
+	writeConfigTenantA(t)
+	cp := newProvider(t, "does_not_exist", true)
+
+	sel, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeProfileNotFound {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeProfileNotFound)
+	}
+	prob, _ := errs.ProblemOf(err)
+	// profile_not_found must carry the credential_source that
+	// named the profile — here the --profile flag.
+	ce := asConfigError(t, err)
+	if ce.CredentialSource != string(credential.SourceFlagProfile) {
+		t.Errorf("credential_source = %q, want %q", ce.CredentialSource, credential.SourceFlagProfile)
+	}
+	assertNoSecretLeak(t, "state6", err.Error(), prob.Hint, string(sel.Source))
+}
+
+// REAL-path regression for review F1: a valid profile whose saved keychain
+// ref is inconsistent with its app_id must surface the precise typed cause —
+// invalid_config, "out of sync", hint naming the expected keychain key — via
+// the actual DefaultAccountProvider, not be flattened into the generic
+// profile_secret_invalid (which is reserved for untyped failures).
+func TestSelection_ProfileKeychainOutOfSyncSurfacesRealCause(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantABroken(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeInvalidConfig {
+		t.Fatalf("subtype = %q, want invalid_config (precise cause, not the generic secret error)", got)
+	}
+	prob, _ := errs.ProblemOf(err)
+	if !strings.Contains(prob.Message, "out of sync") {
+		t.Errorf("message = %q, want the out-of-sync diagnosis", prob.Message)
+	}
+	if !strings.Contains(prob.Hint, "appsecret:cli_a") {
+		t.Errorf("hint = %q, want the expected keychain key named", prob.Hint)
+	}
+	assertNoSecretLeak(t, "keychain-out-of-sync", prob.Message, prob.Hint)
+}
+
+// secretMarkerValue is a distinctive string used to prove that the
+// profile_secret_invalid path drops the underlying error entirely, even when
+// that underlying error's own message CONTAINS a secret. Unlike
+// writeConfigTenantABroken (whose noop-keychain failure is a harmless empty
+// error), this uses a custom DefaultAccountResolver whose error text embeds
+// the marker, closing the gap where a leak could hide in a cause chain that
+// happens to be empty in the noop-keychain case.
+const secretMarkerValue = "your-access-token"
+
+// leakingSecretResolver is a DefaultAccountResolver stub whose ResolveAccount
+// fails with an error whose message contains secretMarkerValue, simulating a
+// real keychain/secret-resolution failure that echoes back sensitive material
+// (e.g. a keychain library including the attempted secret in its error text).
+type leakingSecretResolver struct{}
+
+func (leakingSecretResolver) ResolveAccount(ctx context.Context) (*credential.Account, error) {
+	return nil, fmt.Errorf("keychain decode failed for secret %s", secretMarkerValue)
+}
+
+// When account/secret resolution fails with an error that itself contains a
+// secret, doResolveAccount emits a generic
+// profile_secret_invalid ConfigError WITHOUT attaching the underlying cause,
+// so a secret embedded in that underlying error can never surface through
+// err.Error(), Message, Hint, the unwrapped cause chain, or Selection().
+func TestSelection_ProfileSecretErrorDoesNotLeak(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantA(t) // profile "tenant_a" exists with app_id "cli_a"
+
+	ep := &envprovider.Provider{}
+	cp := credential.NewCredentialProvider([]extcred.Provider{ep}, leakingSecretResolver{}, nil, nil)
+	cp.WithProfileFromFlag("tenant_a")
+
+	sel, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeProfileSecretInvalid {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeProfileSecretInvalid)
+	}
+	ce := asConfigError(t, err)
+	if ce.Profile != "tenant_a" {
+		t.Errorf("profile = %q, want tenant_a", ce.Profile)
+	}
+	if ce.AppID != "cli_a" {
+		t.Errorf("app_id = %q, want cli_a", ce.AppID)
+	}
+
+	// Walk the full unwrap chain. This is the assertion that would catch a
+	// regression where the profile_secret_invalid branch starts attaching the
+	// underlying error via WithCause: if it did, this loop would find the
+	// marker in a wrapped link even though err.Error()/Message/Hint (which
+	// only reflect the top-level ConfigError, not the chain) might look clean.
+	for cur := error(ce); cur != nil; cur = errors.Unwrap(cur) {
+		if strings.Contains(cur.Error(), secretMarkerValue) {
+			t.Errorf("cause chain leaked secret marker: %v", cur)
+		}
+	}
+
+	if strings.Contains(err.Error(), secretMarkerValue) {
+		t.Errorf("err.Error() leaked secret marker: %q", err.Error())
+	}
+	if strings.Contains(ce.Message, secretMarkerValue) {
+		t.Errorf("Message leaked secret marker: %q", ce.Message)
+	}
+	if strings.Contains(ce.Hint, secretMarkerValue) {
+		t.Errorf("Hint leaked secret marker: %q", ce.Hint)
+	}
+	if strings.Contains(string(sel.Source), secretMarkerValue) {
+		t.Errorf("Selection.Source leaked secret marker: %q", sel.Source)
+	}
+	if strings.Contains(sel.DirectCredentialEnv.AppID, secretMarkerValue) {
+		t.Errorf("Selection.DirectCredentialEnv.AppID leaked secret marker: %q", sel.DirectCredentialEnv.AppID)
+	}
+	for _, k := range sel.DirectCredentialEnv.Keys {
+		if strings.Contains(k, secretMarkerValue) {
+			t.Errorf("Selection.DirectCredentialEnv.Keys leaked secret marker: %q", k)
+		}
+	}
+	// The secret-invalid path leaves p.selection zero-valued; this trivially
+	// implies no marker anywhere in it and guards against a future field being populated
+	// from the failed resolution.
+	if sel.Source != "" || sel.DirectCredentialEnv.Present ||
+		sel.DirectCredentialEnv.AppID != "" || len(sel.DirectCredentialEnv.Keys) != 0 {
+		t.Errorf("Selection() = %+v, want zero value on profile_secret_invalid", sel)
+	}
+}
+
+// A profile matching a complete direct env credential wins and records the env as matched.
+func TestSelection_ProfileMatchesCompleteDirectEnv(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_a") // matches profile app_id
+	t.Setenv(envvars.CliAppSecret, envSecretValue)
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if sel.Source != credential.SourceFlagProfile {
+		t.Fatalf("source = %q, want %q", sel.Source, credential.SourceFlagProfile)
+	}
+	if !sel.DirectCredentialEnv.Present || !sel.DirectCredentialEnv.Matched {
+		t.Fatalf("DirectCredentialEnv = %+v, want Present && Matched", sel.DirectCredentialEnv)
+	}
+	if sel.DirectCredentialEnv.AppID != "cli_a" {
+		t.Errorf("DirectCredentialEnv.AppID = %q, want cli_a", sel.DirectCredentialEnv.AppID)
+	}
+	assertNoSecretLeak(t, "state8", string(sel.Source), sel.DirectCredentialEnv.AppID)
+	assertNoSecretLeak(t, "state8-keys", sel.DirectCredentialEnv.Keys...)
+}
+
+// APP_ID-only is sufficient for profile arbitration: a matching selected
+// profile supplies all credentials and tokens, so the incomplete direct env
+// must not block the profile.
+func TestSelection_ProfileMatchesAppIDOnly_ProfileWins(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_a")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	acct, err := cp.ResolveAccount(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if acct.AppID != "cli_a" || acct.AppSecret != secretValue {
+		t.Fatalf("account = %+v, want selected profile credentials", acct)
+	}
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("Selection: %v", err)
+	}
+	if !sel.DirectCredentialEnv.Present || !sel.DirectCredentialEnv.Matched {
+		t.Fatalf("DirectCredentialEnv = %+v, want Present && Matched", sel.DirectCredentialEnv)
+	}
+}
+
+func TestSelection_ProfileMatchingEnvTokens_UsesProfileTokenSource(t *testing.T) {
+	for _, tt := range []struct {
+		name      string
+		tokenType credential.TokenType
+		envKey    string
+	}{
+		{name: "UAT", tokenType: credential.TokenTypeUAT, envKey: envvars.CliUserAccessToken},
+		{name: "TAT", tokenType: credential.TokenTypeTAT, envKey: envvars.CliTenantAccessToken},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv(envvars.CliAppID, "cli_a")
+			t.Setenv(envvars.CliAppSecret, "")
+			t.Setenv(envvars.CliUserAccessToken, "")
+			t.Setenv(envvars.CliTenantAccessToken, "")
+			t.Setenv(tt.envKey, "env-token")
+			writeConfigTenantA(t)
+
+			ep := &envprovider.Provider{}
+			defaultAcct := credential.NewDefaultAccountProvider(func() keychain.KeychainAccess { return &noopKC{} }, "tenant_a")
+			defaultToken := &mockDefaultTokenProvider{token: "profile-token"}
+			cp := credential.NewCredentialProvider([]extcred.Provider{ep}, defaultAcct, defaultToken, nil)
+			cp.WithProfileFromFlag("tenant_a")
+
+			result, err := cp.ResolveToken(context.Background(), credential.TokenSpec{Type: tt.tokenType, AppID: "cli_a"})
+			if err != nil {
+				t.Fatalf("ResolveToken: %v", err)
+			}
+			if result.Token != "profile-token" {
+				t.Fatalf("token = %q, want profile-token (env token must not override selected profile)", result.Token)
+			}
+			sel, err := cp.Selection(context.Background())
+			if err != nil {
+				t.Fatalf("Selection: %v", err)
+			}
+			if sel.Source != credential.SourceFlagProfile || !sel.DirectCredentialEnv.Present || !sel.DirectCredentialEnv.Matched {
+				t.Fatalf("Selection = %+v, want profile source with matched direct env", sel)
+			}
+		})
+	}
+}
+
+// A profile that conflicts with a complete direct env credential reports a hard conflict.
+func TestSelection_ProfileConflictsWithCompleteDirectEnv(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_x") // mismatches profile app_id cli_a
+	t.Setenv(envvars.CliAppSecret, envSecretValue)
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeProfileAppCredentialConflict {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeProfileAppCredentialConflict)
+	}
+	if got := output.ExitCodeOf(err); got != output.ExitValidation {
+		t.Fatalf("exit code = %d, want %d", got, output.ExitValidation)
+	}
+	ve := asValidationError(t, err)
+	if ve.ProfileAppID != "cli_a" {
+		t.Errorf("profile_app_id = %q, want cli_a", ve.ProfileAppID)
+	}
+	if ve.EnvAppID != "cli_x" {
+		t.Errorf("env_app_id = %q, want cli_x", ve.EnvAppID)
+	}
+	if !strings.Contains(ve.Hint, "unset "+envvars.CliAppID+" and "+envvars.CliAppSecret) {
+		t.Errorf("hint = %q, want exact conflicting env variable names", ve.Hint)
+	}
+	assertNoSecretLeak(t, "state9", ve.Message, ve.Hint)
+}
+
+func TestSelection_ProfileConflictsWithAppIDOnly(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_x")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeProfileAppCredentialConflict {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeProfileAppCredentialConflict)
+	}
+	ve := asValidationError(t, err)
+	if ve.ProfileAppID != "cli_a" || ve.EnvAppID != "cli_x" {
+		t.Fatalf("conflict = profile:%q env:%q, want cli_a/cli_x", ve.ProfileAppID, ve.EnvAppID)
+	}
+	if !strings.Contains(ve.Hint, "unset "+envvars.CliAppID) {
+		t.Errorf("hint = %q, want exact APP_ID unset instruction", ve.Hint)
+	}
+}
+
+func TestSelection_ExplicitMissingProfileWinsOverIncompleteEnv(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_a")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_typo", false)
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeProfileNotFound {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeProfileNotFound)
+	}
+	ce := asConfigError(t, err)
+	if ce.Profile != "tenant_typo" || ce.CredentialSource != string(credential.SourceEnvProfile) {
+		t.Fatalf("profile error = %+v, want tenant_typo from env profile", ce)
+	}
+}
+
+func TestSelection_ExplicitProfileMalformedConfigWinsOverIncompleteEnv(t *testing.T) {
+	writeMalformedConfig(t)
+	t.Setenv(envvars.CliAppSecret, "direct-value")
+	cp := newProvider(t, "tenant_a", true)
+
+	_, err := cp.Selection(context.Background())
+	assertMalformedSurfaced(t, err)
+}
+
+// A direct secret or token without APP_ID remains incomplete even when a valid profile is selected.
+func TestSelection_ProfileWithDirectEnvMissingAppID(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		key  string
+	}{
+		{name: "APP_SECRET-only", key: envvars.CliAppSecret},
+		{name: "UAT-only", key: envvars.CliUserAccessToken},
+		{name: "TAT-only", key: envvars.CliTenantAccessToken},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv(envvars.CliAppID, "")
+			t.Setenv(envvars.CliAppSecret, "")
+			t.Setenv(envvars.CliUserAccessToken, "")
+			t.Setenv(envvars.CliTenantAccessToken, "")
+			t.Setenv(tt.key, "direct-value")
+			writeConfigTenantA(t)
+			cp := newProvider(t, "tenant_a", true)
+
+			_, err := cp.Selection(context.Background())
+			if got := subtypeOf(t, err); got != errs.SubtypeAppCredentialIncomplete {
+				t.Fatalf("subtype = %q, want %q", got, errs.SubtypeAppCredentialIncomplete)
+			}
+			if got := output.ExitCodeOf(err); got != output.ExitAuth {
+				t.Fatalf("exit code = %d, want %d", got, output.ExitAuth)
+			}
+			ce := asConfigError(t, err)
+			if !slices.Equal(ce.MissingKeys, []string{envvars.CliAppID}) {
+				t.Errorf("missing_keys = %v, want [%s]", ce.MissingKeys, envvars.CliAppID)
+			}
+			wantHint := "set " + envvars.CliAppID + ", or unset " + tt.key + " to use the selected profile."
+			if ce.Hint != wantHint {
+				t.Errorf("hint = %q, want %q", ce.Hint, wantHint)
+			}
+			var blockErr *extcred.BlockError
+			if !errors.As(err, &blockErr) || blockErr.Code != extcred.BlockReasonCredentialIncomplete {
+				t.Fatalf("cause chain does not preserve credential BlockError: %T %v", err, err)
+			}
+			assertNoSecretLeak(t, "state10", ce.Message, ce.Hint)
+			assertNoSecretLeak(t, "state10-keys", ce.MissingKeys...)
+		})
+	}
+}
+
+// An invalid policy variable is a user input mistake: it must surface as a
+// typed validation error (exit 2) carrying the variable name in param and a
+// repair hint — never as an internal error, and never rewritten into
+// app_credential_incomplete. The original BlockError stays on the cause chain.
+func TestSelection_InvalidPolicyEnvBlockBecomesTypedValidation(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		key  string
+	}{
+		{name: "invalid DEFAULT_AS", key: envvars.CliDefaultAs},
+		{name: "invalid STRICT_MODE", key: envvars.CliStrictMode},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Setenv(envvars.CliAppID, "cli_a")
+			t.Setenv(envvars.CliAppSecret, "")
+			t.Setenv(envvars.CliUserAccessToken, "")
+			t.Setenv(envvars.CliTenantAccessToken, "")
+			t.Setenv(tt.key, "banana")
+			writeConfigTenantA(t)
+			cp := newProvider(t, "tenant_a", true)
+
+			_, err := cp.Selection(context.Background())
+			if got := subtypeOf(t, err); got != errs.SubtypeInvalidArgument {
+				t.Fatalf("subtype = %q, want %q", got, errs.SubtypeInvalidArgument)
+			}
+			if got := output.ExitCodeOf(err); got != output.ExitValidation {
+				t.Fatalf("exit code = %d, want validation %d", got, output.ExitValidation)
+			}
+			ve := asValidationError(t, err)
+			if ve.Param != tt.key {
+				t.Errorf("param = %q, want %q", ve.Param, tt.key)
+			}
+			if !strings.Contains(ve.Message, tt.key) || !strings.Contains(ve.Message, "banana") {
+				t.Errorf("message = %q, want the variable name and its invalid value", ve.Message)
+			}
+			if !strings.Contains(ve.Hint, tt.key) {
+				t.Errorf("hint = %q, want repair guidance naming %s", ve.Hint, tt.key)
+			}
+			var blockErr *extcred.BlockError
+			if !errors.As(err, &blockErr) || blockErr.Code != extcred.BlockReasonInvalidPolicy {
+				t.Fatalf("cause chain does not preserve the invalid-policy BlockError: %T %v", err, err)
+			}
+			if strings.Contains(err.Error(), string(errs.SubtypeAppCredentialIncomplete)) {
+				t.Fatalf("error was rewritten as app_credential_incomplete: %v", err)
+			}
+		})
+	}
+}
+
+func TestActiveExtensionProviderName_MatchingAppIDOnlyProfileUsesBuiltin(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "cli_a")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+	cp := newProvider(t, "tenant_a", true)
+
+	name, err := cp.ActiveExtensionProviderName(context.Background())
+	if err != nil {
+		t.Fatalf("ActiveExtensionProviderName: %v", err)
+	}
+	if name != "" {
+		t.Fatalf("provider name = %q, want builtin profile (empty)", name)
+	}
+}
+
+// A failed profile resolution must neither propagate its error nor report an
+// external takeover: this probe guards the builtin setup/repair commands
+// (auth, config), which must stay usable to fix exactly these states. It
+// falls back to the engagement probe instead.
+func TestActiveExtensionProviderName_ProfileResolutionFailureFallsBackToProbe(t *testing.T) {
+	t.Run("no provider engaged, stale profile -> builtin allowed", func(t *testing.T) {
+		t.Setenv(envvars.CliAppID, "")
+		t.Setenv(envvars.CliAppSecret, "")
+		t.Setenv(envvars.CliUserAccessToken, "")
+		t.Setenv(envvars.CliTenantAccessToken, "")
+		t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir()) // no config -> profile_not_found
+		cp := newProvider(t, "ghost", false)
+
+		name, err := cp.ActiveExtensionProviderName(context.Background())
+		if err != nil || name != "" {
+			t.Fatalf("ActiveExtensionProviderName = %q, %v; want \"\", nil", name, err)
+		}
+	})
+	t.Run("engaged env provider still reported on conflict", func(t *testing.T) {
+		t.Setenv(envvars.CliAppID, "cli_x") // conflicts with tenant_a -> resolution fails
+		t.Setenv(envvars.CliAppSecret, envSecretValue)
+		t.Setenv(envvars.CliUserAccessToken, "")
+		t.Setenv(envvars.CliTenantAccessToken, "")
+		writeConfigTenantA(t)
+		cp := newProvider(t, "tenant_a", true)
+
+		name, err := cp.ActiveExtensionProviderName(context.Background())
+		if err != nil || name != "env" {
+			t.Fatalf("ActiveExtensionProviderName = %q, %v; want \"env\", nil", name, err)
+		}
+	})
+}
+
+// stubFailureResolver fails ResolveAccount with a fixed error.
+type stubFailureResolver struct{ err error }
+
+func (s *stubFailureResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return nil, s.err
+}
+
+// stubAccountResolver returns a fixed account.
+type stubAccountResolver struct{ acct *credential.Account }
+
+func (s *stubAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return s.acct, nil
+}
+
+// Contract test: ANY typed resolver failure (other than not_configured) on
+// the profile route passes through with its own subtype and hint. The
+// real-path proof for the keychain out-of-sync case is
+// TestSelection_ProfileKeychainOutOfSyncSurfacesRealCause above.
+func TestSelection_ProfileTypedResolverFailurePassesThrough(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+
+	typed := errs.NewValidationError(errs.SubtypeFailedPrecondition,
+		"credential backend rejected the stored profile").
+		WithHint("repair the stored profile input.")
+	cp := credential.NewCredentialProvider(
+		[]extcred.Provider{&envprovider.Provider{}}, &stubFailureResolver{err: typed}, nil, nil)
+	cp.WithProfileFromFlag("tenant_a")
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeFailedPrecondition {
+		t.Fatalf("subtype = %q, want the typed failure passed through", got)
+	}
+	if strings.Contains(err.Error(), "could not be resolved locally") {
+		t.Fatalf("typed failure was flattened into the generic secret error: %v", err)
+	}
+}
+
+// An untyped resolver failure must stay masked behind the generic secret
+// error: its content is not guaranteed secret-free.
+func TestSelection_ProfileUntypedResolverFailureStaysGeneric(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+
+	cp := credential.NewCredentialProvider(
+		[]extcred.Provider{&envprovider.Provider{}},
+		&stubFailureResolver{err: fmt.Errorf("read keychain: %s", secretValue)}, nil, nil)
+	cp.WithProfileFromFlag("tenant_a")
+
+	_, err := cp.Selection(context.Background())
+	if got := subtypeOf(t, err); got != errs.SubtypeProfileSecretInvalid {
+		t.Fatalf("subtype = %q, want %q", got, errs.SubtypeProfileSecretInvalid)
+	}
+	assertNoSecretLeak(t, "untyped-resolver-failure", err.Error())
+}
+
+// The resolver re-reads the config after arbitration validated the snapshot;
+// if a concurrent edit hands back a different app, the mismatch must be
+// refused rather than silently using credentials arbitration never checked.
+func TestSelection_ProfileResolverAppIDMismatchRefused(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t) // snapshot sees tenant_a -> cli_a
+
+	cp := credential.NewCredentialProvider(
+		[]extcred.Provider{&envprovider.Provider{}},
+		&stubAccountResolver{acct: &credential.Account{AppID: "cli_other", AppSecret: secretValue}}, nil, nil)
+	cp.WithProfileFromFlag("tenant_a")
+
+	_, err := cp.Selection(context.Background())
+	if err == nil {
+		t.Fatal("expected error for app_id mismatch between snapshot and resolver")
+	}
+	if !strings.Contains(err.Error(), "config changed during resolution") {
+		t.Fatalf("error = %v, want config-changed refusal", err)
+	}
+}
+
+// A config that exists but cannot be read (permission denied) must surface
+// invalid_config with the real cause — not profile_not_found (the profile may
+// well exist in the unreadable file) and not no_active_profile.
+func TestSelection_UnreadableConfigSurfacesRealCause(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("relies on POSIX file permissions")
+	}
+	if os.Geteuid() == 0 {
+		t.Skip("root bypasses file permissions")
+	}
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv(envvars.CliUserAccessToken, "")
+	t.Setenv(envvars.CliTenantAccessToken, "")
+	writeConfigTenantA(t)
+	path := core.GetConfigPath()
+	if err := os.Chmod(path, 0o000); err != nil {
+		t.Fatalf("chmod: %v", err)
+	}
+	t.Cleanup(func() { _ = os.Chmod(path, 0o600) })
+
+	t.Run("explicit profile", func(t *testing.T) {
+		cp := newProvider(t, "tenant_a", true)
+		_, err := cp.Selection(context.Background())
+		if got := subtypeOf(t, err); got != errs.SubtypeInvalidConfig {
+			t.Fatalf("subtype = %q, want invalid_config (not profile_not_found)", got)
+		}
+	})
+	t.Run("config default", func(t *testing.T) {
+		cp := newProvider(t, "", false)
+		_, err := cp.Selection(context.Background())
+		if got := subtypeOf(t, err); got != errs.SubtypeInvalidConfig {
+			t.Fatalf("subtype = %q, want invalid_config (not no_active_profile)", got)
+		}
+	})
+}
+
+// fakeSidecarProvider is a NON-env extension provider (Priority 0, Name !=
+// directCredentialProviderName) that always returns a non-nil account. It
+// stands in for the sidecar extension provider without needing a build tag.
+type fakeSidecarProvider struct {
+	appID string
+}
+
+func (f *fakeSidecarProvider) Name() string  { return "sidecar" }
+func (f *fakeSidecarProvider) Priority() int { return 0 }
+func (f *fakeSidecarProvider) ResolveAccount(ctx context.Context) (*extcred.Account, error) {
+	return &extcred.Account{AppID: f.appID, Brand: extcred.Brand("feishu")}, nil
+}
+func (f *fakeSidecarProvider) ResolveToken(ctx context.Context, req extcred.TokenSpec) (*extcred.Token, error) {
+	return &extcred.Token{Value: "sidecar-tok", Source: "sidecar"}, nil
+}
+
+// Regression: a NON-env extension provider (sidecar) that returns a managed
+// account must win outright even when a profile is set. It must NOT be treated
+// as a direct-credential env account: no profile arbitration, no
+// profile_app_credential_conflict (even though its app_id differs from the
+// profile's cli_a), and DirectCredentialEnv.Present must stay false because no
+// direct env vars are set. The selection source names the provider explicitly.
+func TestSelection_NonEnvExtensionProviderWinsOverProfile(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")     // no direct env credential
+	t.Setenv(envvars.CliAppSecret, "") // no direct env credential
+	writeConfigTenantA(t)              // profile tenant_a exists, app_id cli_a
+
+	sidecar := &fakeSidecarProvider{appID: "sidecar_app"} // differs from cli_a
+	defaultAcct := credential.NewDefaultAccountProvider(func() keychain.KeychainAccess { return &noopKC{} }, "tenant_a")
+	cp := credential.NewCredentialProvider([]extcred.Provider{sidecar}, defaultAcct, nil, nil)
+	cp.WithProfileFromFlag("tenant_a")
+
+	acct, err := cp.ResolveAccount(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// The sidecar account is used as-is, NOT overridden by profile arbitration.
+	if acct == nil || acct.AppID != "sidecar_app" {
+		t.Fatalf("account = %+v, want AppID sidecar_app (sidecar wins outright)", acct)
+	}
+
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected Selection error: %v", err)
+	}
+	// No misreported direct env credential.
+	if sel.DirectCredentialEnv.Present {
+		t.Errorf("DirectCredentialEnv.Present = true, want false (no direct env vars set)")
+	}
+	if sel.Source != credential.SourceExtension("sidecar") {
+		t.Errorf("source = %q, want %q", sel.Source, credential.SourceExtension("sidecar"))
+	}
+	// The mismatched app_id (sidecar_app vs profile cli_a) must NOT trigger a
+	// profile_app_credential_conflict: both ResolveAccount and Selection above
+	// returned nil errors, so no conflict (or any other) error was produced.
+	// Guard against a future regression that surfaces a conflict via Selection.
+	if _, selErr := cp.Selection(context.Background()); selErr != nil {
+		if subtypeOf(t, selErr) == errs.SubtypeProfileAppCredentialConflict {
+			t.Errorf("got profile_app_credential_conflict, want none for non-env provider")
+		}
+	}
+	assertNoSecretLeak(t, "nonenv-sidecar", string(sel.Source), sel.DirectCredentialEnv.AppID)
+}
+
+// Without an explicit profile or direct credential, selection uses the configured current app.
+func TestSelection_ConfigDefault(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	writeConfigTenantA(t) // CurrentApp = tenant_a
+	cp := newProvider(t, "", false)
+
+	sel, err := cp.Selection(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if sel.Source != credential.SourceConfigCurrentApp {
+		t.Fatalf("source = %q, want %q", sel.Source, credential.SourceConfigCurrentApp)
+	}
+}
+
+// forgedDirectProvider impersonates the builtin env provider by name and
+// declares AccountDirect. The reservation must hold by concrete type, not by
+// the forgeable Name() string.
+type forgedDirectProvider struct{}
+
+func (forgedDirectProvider) Name() string  { return "env" }
+func (forgedDirectProvider) Priority() int { return 0 }
+func (forgedDirectProvider) ResolveAccount(context.Context) (*extcred.Account, error) {
+	return &extcred.Account{AppID: "forged_app", Kind: extcred.AccountDirect}, nil
+}
+func (forgedDirectProvider) ResolveToken(context.Context, extcred.TokenSpec) (*extcred.Token, error) {
+	return nil, nil
+}
+
+func TestSelection_ForgedDirectProviderRejected(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+
+	cp := credential.NewCredentialProvider([]extcred.Provider{forgedDirectProvider{}}, nil, nil, nil)
+	_, err := cp.ResolveAccount(context.Background())
+	if err == nil || !strings.Contains(err.Error(), "reserved for the builtin env provider") {
+		t.Fatalf("err = %v, want AccountDirect reservation failure for a name-forging provider", err)
+	}
+}
+
+// forgedIncompleteProvider exercises the public SPI boundary: although it
+// supplies provider-owned metadata, credential_incomplete is reserved for the
+// builtin env provider while arbitration diagnostics name LARKSUITE_CLI_*.
+type forgedIncompleteProvider struct{}
+
+func (forgedIncompleteProvider) Name() string  { return "vault" }
+func (forgedIncompleteProvider) Priority() int { return 0 }
+func (forgedIncompleteProvider) ResolveAccount(context.Context) (*extcred.Account, error) {
+	return nil, &extcred.BlockError{
+		Provider:    "vault",
+		Reason:      "vault app credential is incomplete",
+		Code:        extcred.BlockReasonCredentialIncomplete,
+		AppID:       "vault_app",
+		PresentKeys: []string{"VAULT_APP_ID"},
+	}
+}
+func (forgedIncompleteProvider) ResolveToken(context.Context, extcred.TokenSpec) (*extcred.Token, error) {
+	return nil, nil
+}
+
+func TestSelection_NonEnvCredentialIncompleteRejected(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliAppSecret, "")
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+
+	providers := []extcred.Provider{forgedIncompleteProvider{}}
+	probeCP := credential.NewCredentialProvider(providers, nil, nil, nil)
+	name, probeErr := probeCP.ActiveExtensionProviderName(context.Background())
+	if name != "" {
+		t.Fatalf("provider name = %q, want none for an invalid SPI classification", name)
+	}
+
+	arbCP := credential.NewCredentialProvider(providers, nil, nil, nil)
+	_, arbErr := arbCP.ResolveAccount(context.Background())
+	for label, err := range map[string]error{"probe": probeErr, "arbitration": arbErr} {
+		if err == nil || !strings.Contains(err.Error(), "reserved for the builtin env provider") {
+			t.Fatalf("%s err = %v, want credential_incomplete reservation failure for a non-env provider", label, err)
+		}
+		if got := subtypeOf(t, err); got != errs.SubtypeUnknown {
+			t.Fatalf("%s subtype = %q, want unknown internal contract violation", label, got)
+		}
+	}
+	if probeErr.Error() != arbErr.Error() {
+		t.Fatalf("probe and arbitration diverge:\n  probe: %v\n  arbitration: %v", probeErr, arbErr)
+	}
+}
+
+// policyBlockProvider blocks with an invalid_policy classification, standing
+// in for the env provider having seen a bad LARKSUITE_CLI_DEFAULT_AS.
+type policyBlockProvider struct{}
+
+func (policyBlockProvider) Name() string  { return "env" }
+func (policyBlockProvider) Priority() int { return 0 }
+func (policyBlockProvider) ResolveAccount(context.Context) (*extcred.Account, error) {
+	return nil, &extcred.BlockError{
+		Provider: "env",
+		Reason:   "invalid LARKSUITE_CLI_DEFAULT_AS \"banana\" (want user, bot, or auto)",
+		Code:     extcred.BlockReasonInvalidPolicy,
+		Param:    envvars.CliDefaultAs,
+	}
+}
+func (policyBlockProvider) ResolveToken(context.Context, extcred.TokenSpec) (*extcred.Token, error) {
+	return nil, nil
+}
+
+// The gate probe must stay aligned with formal arbitration when multiple
+// providers are registered: provider A's invalid_policy block surfaces as the
+// same typed validation error in both, instead of the probe scanning on and
+// blaming provider B as an external takeover.
+func TestActiveExtensionProviderName_InvalidPolicyAlignsWithArbitration(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	providers := []extcred.Provider{policyBlockProvider{}, &fakeSidecarProvider{appID: "sidecar_app"}}
+
+	probeCP := credential.NewCredentialProvider(providers, nil, nil, nil)
+	name, probeErr := probeCP.ActiveExtensionProviderName(context.Background())
+	if name != "" {
+		t.Fatalf("provider name = %q, want none (no external takeover)", name)
+	}
+	if got := subtypeOf(t, probeErr); got != errs.SubtypeInvalidArgument {
+		t.Fatalf("probe subtype = %q, want invalid_argument", got)
+	}
+
+	arbCP := credential.NewCredentialProvider(providers, nil, nil, nil)
+	_, arbErr := arbCP.ResolveAccount(context.Background())
+	if got := subtypeOf(t, arbErr); got != errs.SubtypeInvalidArgument {
+		t.Fatalf("arbitration subtype = %q, want invalid_argument", got)
+	}
+	if probeErr.Error() != arbErr.Error() {
+		t.Fatalf("probe and arbitration diverge:\n  probe: %v\n  arbitration: %v", probeErr, arbErr)
+	}
+}
diff --git a/internal/credential/credential_provider_test.go b/internal/credential/credential_provider_test.go
index 6dd13a985d..c54bddb662 100644
--- a/internal/credential/credential_provider_test.go
+++ b/internal/credential/credential_provider_test.go
@@ -11,6 +11,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/larksuite/cli/errs"
 	extcred "github.com/larksuite/cli/extension/credential"
 	"github.com/larksuite/cli/internal/auth"
 	"github.com/larksuite/cli/internal/core"
@@ -23,6 +24,7 @@ type mockExtProvider struct {
 	err        error
 	accountErr error
 	tokenErr   error
+	tokenCalls int
 }
 
 func (m *mockExtProvider) Name() string { return m.name }
@@ -33,6 +35,7 @@ func (m *mockExtProvider) ResolveAccount(ctx context.Context) (*extcred.Account,
 	return m.account, m.err
 }
 func (m *mockExtProvider) ResolveToken(ctx context.Context, req extcred.TokenSpec) (*extcred.Token, error) {
+	m.tokenCalls++
 	if m.tokenErr != nil {
 		return nil, m.tokenErr
 	}
@@ -49,11 +52,13 @@ func (m *mockDefaultAcct) ResolveAccount(ctx context.Context) (*Account, error)
 }
 
 type mockDefaultToken struct {
-	result *TokenResult
-	err    error
+	result     *TokenResult
+	err        error
+	tokenCalls int
 }
 
 func (m *mockDefaultToken) ResolveToken(ctx context.Context, req TokenSpec) (*TokenResult, error) {
+	m.tokenCalls++
 	return m.result, m.err
 }
 
@@ -116,35 +121,45 @@ func TestCredentialProvider_AccountCached(t *testing.T) {
 }
 
 func TestCredentialProvider_TokenFromExtension(t *testing.T) {
-	cp := NewCredentialProvider(
-		[]extcred.Provider{&mockExtProvider{
-			name:    "env",
-			account: &extcred.Account{AppID: "ext_app", Brand: "feishu"},
-			token:   &extcred.Token{Value: "ext_tok", Source: "env"},
-		}},
-		&mockDefaultAcct{}, &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}, nil,
-	)
-	result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if result.Token != "ext_tok" {
-		t.Errorf("expected ext_tok, got %s", result.Token)
+	for _, sourceName := range []string{"env", "authsidecar"} {
+		t.Run(sourceName, func(t *testing.T) {
+			cp := NewCredentialProvider(
+				[]extcred.Provider{&mockExtProvider{
+					name:    sourceName,
+					account: &extcred.Account{AppID: "ext_app", Brand: "feishu"},
+					token:   &extcred.Token{Value: "ext_tok", Source: sourceName},
+				}},
+				&mockDefaultAcct{account: &Account{AppID: "default_app"}},
+				&mockDefaultToken{result: &TokenResult{Token: "default_tok"}}, nil,
+			)
+			result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "ext_app"})
+			if err != nil {
+				t.Fatal(err)
+			}
+			if result.Token != "ext_tok" {
+				t.Errorf("expected ext_tok, got %s", result.Token)
+			}
+		})
 	}
 }
 
 func TestCredentialProvider_TokenFallsToDefault(t *testing.T) {
+	defaultToken := &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}
 	cp := NewCredentialProvider(
 		[]extcred.Provider{&mockExtProvider{name: "skip"}},
-		&mockDefaultAcct{}, &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}, nil,
+		&mockDefaultAcct{account: &Account{AppID: "default_app"}},
+		defaultToken, nil,
 	)
-	result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
+	result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "default_app"})
 	if err != nil {
 		t.Fatal(err)
 	}
 	if result.Token != "default_tok" {
 		t.Errorf("expected default_tok, got %s", result.Token)
 	}
+	if defaultToken.tokenCalls != 1 {
+		t.Fatalf("default ResolveToken() calls = %d, want 1", defaultToken.tokenCalls)
+	}
 }
 
 func TestCredentialProvider_TokenDoesNotMixSourcesAfterDefaultAccountSelection(t *testing.T) {
@@ -159,7 +174,7 @@ func TestCredentialProvider_TokenDoesNotMixSourcesAfterDefaultAccountSelection(t
 		t.Fatalf("ResolveAccount() error = %v", err)
 	}
 
-	result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
+	result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "default_app"})
 	if err != nil {
 		t.Fatalf("ResolveToken() error = %v", err)
 	}
@@ -181,7 +196,7 @@ func TestCredentialProvider_SelectedSourceWithoutTokenReturnsUnavailableError(t
 		t.Fatalf("ResolveAccount() error = %v", err)
 	}
 
-	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
+	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "ext_app"})
 	if err == nil {
 		t.Fatal("ResolveToken() error = nil, want unavailable error")
 	}
@@ -202,7 +217,7 @@ func TestCredentialProvider_ResolveTokenPropagatesNonBlockExtensionError(t *test
 		nil,
 	)
 
-	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
+	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "ext_app"})
 	if err == nil || err.Error() != "provider exploded" {
 		t.Fatalf("ResolveToken() error = %v, want provider exploded", err)
 	}
@@ -312,12 +327,12 @@ func TestCredentialProvider_ResolveIdentityHint_CachesResult(t *testing.T) {
 func TestCredentialProvider_ResolveTokenTreatsEmptyDefaultTokenAsMalformed(t *testing.T) {
 	cp := NewCredentialProvider(
 		nil,
-		nil,
+		&mockDefaultAcct{account: &Account{AppID: "default_app"}},
 		&mockDefaultToken{result: &TokenResult{Token: ""}},
 		nil,
 	)
 
-	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
+	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "default_app"})
 	if err == nil || !strings.Contains(err.Error(), "empty token") {
 		t.Fatalf("ResolveToken() error = %v, want malformed empty token error", err)
 	}
@@ -410,17 +425,189 @@ func TestCredentialProvider_ResolveAccountWarnsWhenExtensionIdentityVerification
 }
 
 func TestCredentialProvider_ResolveTokenDoesNotBypassFailedDefaultAccountResolution(t *testing.T) {
+	defaultToken := &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}
 	cp := NewCredentialProvider(
 		nil,
 		&mockDefaultAcct{err: errors.New("config unavailable")},
-		&mockDefaultToken{result: &TokenResult{Token: "default_tok"}},
+		defaultToken,
 		nil,
 	)
 
-	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT})
+	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "default_app"})
 	if err == nil || err.Error() != "config unavailable" {
 		t.Fatalf("ResolveToken() error = %v, want config unavailable", err)
 	}
+	if defaultToken.tokenCalls != 0 {
+		t.Fatalf("default ResolveToken() calls = %d, want 0", defaultToken.tokenCalls)
+	}
+}
+
+func TestCredentialProvider_ResolveTokenRejectsUnboundAppBeforeExtensionIO(t *testing.T) {
+	tests := []struct {
+		name  string
+		appID string
+	}{
+		{name: "empty app id"},
+		{name: "different app id", appID: "other_app"},
+	}
+
+	for _, tt := range tests {
+		for _, sourceName := range []string{"env", "authsidecar"} {
+			t.Run(tt.name+"/"+sourceName, func(t *testing.T) {
+				provider := &mockExtProvider{
+					name:    sourceName,
+					account: &extcred.Account{AppID: "ext_app", Brand: "feishu"},
+					token:   &extcred.Token{Value: "ext_tok", Source: sourceName},
+				}
+				httpClientCalls := 0
+				cp := NewCredentialProvider(
+					[]extcred.Provider{provider},
+					&mockDefaultAcct{account: &Account{AppID: "default_app"}},
+					&mockDefaultToken{result: &TokenResult{Token: "default_tok"}},
+					func() (*http.Client, error) {
+						httpClientCalls++
+						return nil, errors.New("unexpected user_info call")
+					},
+				)
+
+				_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: tt.appID})
+				if err == nil {
+					t.Fatal("ResolveToken() error = nil, want app binding error")
+				}
+				assertInternalUnknownWithRetryHint(t, err)
+				if provider.tokenCalls != 0 {
+					t.Fatalf("extension ResolveToken() calls = %d, want 0", provider.tokenCalls)
+				}
+				if httpClientCalls != 0 {
+					t.Fatalf("httpClient() calls = %d, want 0", httpClientCalls)
+				}
+			})
+		}
+	}
+}
+
+func TestCredentialProvider_ResolveTokenRejectsUnboundAppBeforeDefaultIO(t *testing.T) {
+	tests := []struct {
+		name  string
+		appID string
+	}{
+		{name: "empty app id"},
+		{name: "different app id", appID: "other_app"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			defaultToken := &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}
+			cp := NewCredentialProvider(
+				nil,
+				&mockDefaultAcct{account: &Account{AppID: "default_app"}},
+				defaultToken,
+				nil,
+			)
+
+			_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: tt.appID})
+			if err == nil {
+				t.Fatal("ResolveToken() error = nil, want app binding error")
+			}
+			assertInternalUnknownWithRetryHint(t, err)
+			if defaultToken.tokenCalls != 0 {
+				t.Fatalf("default ResolveToken() calls = %d, want 0", defaultToken.tokenCalls)
+			}
+		})
+	}
+}
+
+func TestCredentialProvider_ResolveTokenRejectsNilAccountBeforeTokenIO(t *testing.T) {
+	defaultToken := &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}
+	cp := NewCredentialProvider(
+		nil,
+		&mockDefaultAcct{},
+		defaultToken,
+		nil,
+	)
+
+	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "requested_app"})
+	if err == nil {
+		t.Fatal("ResolveToken() error = nil, want nil account error")
+	}
+	assertInternalUnknownWithRetryHint(t, err)
+	if defaultToken.tokenCalls != 0 {
+		t.Fatalf("default ResolveToken() calls = %d, want 0", defaultToken.tokenCalls)
+	}
+}
+
+func TestCredentialProvider_ResolveTokenRejectsMissingSelectedSourceWithoutFallback(t *testing.T) {
+	extension := &mockExtProvider{
+		name:  "env",
+		token: &extcred.Token{Value: "ext_tok", Source: "env"},
+	}
+	defaultToken := &mockDefaultToken{result: &TokenResult{Token: "default_tok"}}
+	cp := NewCredentialProvider(
+		[]extcred.Provider{extension},
+		&mockDefaultAcct{account: &Account{AppID: "default_app"}},
+		defaultToken,
+		nil,
+	)
+	cp.account = &Account{AppID: "selected_app"}
+	cp.accountOnce.Do(func() {})
+
+	_, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "selected_app"})
+	if err == nil {
+		t.Fatal("ResolveToken() error = nil, want missing selected source error")
+	}
+	assertInternalUnknownWithRetryHint(t, err)
+	if extension.tokenCalls != 0 {
+		t.Fatalf("extension ResolveToken() calls = %d, want 0", extension.tokenCalls)
+	}
+	if defaultToken.tokenCalls != 0 {
+		t.Fatalf("default ResolveToken() calls = %d, want 0", defaultToken.tokenCalls)
+	}
+}
+
+func TestCredentialProvider_ResolveTokenMatchingExtensionDoesNotEnrichIdentity(t *testing.T) {
+	provider := &mockExtProvider{
+		name:    "env",
+		account: &extcred.Account{AppID: "ext_app", Brand: "feishu"},
+		token:   &extcred.Token{Value: "ext_tok", Source: "env"},
+	}
+	httpClientCalls := 0
+	cp := NewCredentialProvider(
+		[]extcred.Provider{provider},
+		nil,
+		nil,
+		func() (*http.Client, error) {
+			httpClientCalls++
+			return nil, errors.New("unexpected user_info call")
+		},
+	)
+
+	result, err := cp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "ext_app"})
+	if err != nil {
+		t.Fatalf("ResolveToken() error = %v", err)
+	}
+	if result.Token != "ext_tok" {
+		t.Fatalf("ResolveToken() token = %q, want %q", result.Token, "ext_tok")
+	}
+	if provider.tokenCalls != 1 {
+		t.Fatalf("extension ResolveToken() calls = %d, want 1", provider.tokenCalls)
+	}
+	if httpClientCalls != 0 {
+		t.Fatalf("httpClient() calls = %d, want 0", httpClientCalls)
+	}
+}
+
+func assertInternalUnknownWithRetryHint(t *testing.T, err error) {
+	t.Helper()
+	problem, ok := errs.ProblemOf(err)
+	if !ok {
+		t.Fatalf("error type = %T, want typed internal error", err)
+	}
+	if problem.Category != errs.CategoryInternal || problem.Subtype != errs.SubtypeUnknown {
+		t.Fatalf("error problem = %+v, want internal/unknown", problem)
+	}
+	if problem.Hint != "retry the command." {
+		t.Fatalf("error hint = %q, want retry hint", problem.Hint)
+	}
 }
 
 func TestActiveExtensionProviderName_ExtActive(t *testing.T) {
diff --git a/internal/credential/decide_test.go b/internal/credential/decide_test.go
new file mode 100644
index 0000000000..8e8aa87630
--- /dev/null
+++ b/internal/credential/decide_test.go
@@ -0,0 +1,181 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package credential
+
+import (
+	"context"
+	"testing"
+
+	"github.com/larksuite/cli/errs"
+	extcred "github.com/larksuite/cli/extension/credential"
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/envvars"
+)
+
+// stubDecideProvider satisfies extcred.Provider for building providerAccount
+// literals; decideIdentity only ever calls Name() on it.
+type stubDecideProvider struct{ name string }
+
+func (s stubDecideProvider) Name() string  { return s.name }
+func (s stubDecideProvider) Priority() int { return 0 }
+func (s stubDecideProvider) ResolveAccount(context.Context) (*extcred.Account, error) {
+	return nil, nil
+}
+func (s stubDecideProvider) ResolveToken(context.Context, extcred.TokenSpec) (*extcred.Token, error) {
+	return nil, nil
+}
+
+func pa(providerName, appID string) *providerAccount {
+	return &providerAccount{
+		acct:   &Account{AppID: appID},
+		source: extensionTokenSource{provider: stubDecideProvider{name: providerName}},
+	}
+}
+
+func appIDOnlyBlock(appID string) *extcred.BlockError {
+	return &extcred.BlockError{
+		Provider:      "env",
+		Reason:        envvars.CliAppID + " is set but no app secret or access token is available",
+		Code:          extcred.BlockReasonCredentialIncomplete,
+		RequiredAnyOf: []string{envvars.CliAppSecret, envvars.CliUserAccessToken, envvars.CliTenantAccessToken},
+		PresentKeys:   []string{envvars.CliAppID},
+		AppID:         appID,
+	}
+}
+
+func uatOnlyBlock() *extcred.BlockError {
+	return &extcred.BlockError{
+		Provider:    "env",
+		Reason:      envvars.CliUserAccessToken + " is set but " + envvars.CliAppID + " is missing",
+		Code:        extcred.BlockReasonCredentialIncomplete,
+		MissingKeys: []string{envvars.CliAppID},
+		PresentKeys: []string{envvars.CliUserAccessToken},
+	}
+}
+
+// TestDecideIdentity exercises the selection matrix as data: decideIdentity is
+// pure, so every rule (precedence, conflict detection, error attribution) is
+// table-testable without env vars or config fixtures.
+func TestDecideIdentity(t *testing.T) {
+	tenantA := &core.MultiAppConfig{
+		CurrentApp: "tenant_a",
+		Apps:       []core.AppConfig{{Name: "tenant_a", AppId: "cli_a"}},
+	}
+	noCurrent := &core.MultiAppConfig{
+		Apps: []core.AppConfig{{Name: "tenant_a", AppId: "cli_a"}},
+	}
+	invalidConfigErr := errs.NewConfigError(errs.SubtypeInvalidConfig, "invalid config format")
+	notConfiguredErr := core.NotConfiguredError()
+
+	cases := []struct {
+		name    string
+		in      identityInputs
+		route   credentialRoute
+		source  CredentialSourceKind
+		matched bool
+		subtype errs.Subtype // "" = success expected
+	}{
+		{
+			name:   "managed provider wins over explicit profile",
+			in:     identityInputs{profile: "tenant_a", profileSrc: SourceFlagProfile, managed: pa("sidecar", "sidecar_app"), config: tenantA},
+			route:  routeManaged,
+			source: SourceExtension("sidecar"),
+		},
+		{
+			name:    "profile conflicts with complete direct env app_id",
+			in:      identityInputs{profile: "tenant_a", profileSrc: SourceFlagProfile, direct: pa("env", "cli_x"), directKeys: []string{envvars.CliAppID, envvars.CliAppSecret}, config: tenantA},
+			subtype: errs.SubtypeProfileAppCredentialConflict,
+		},
+		{
+			name:    "matched complete direct env yields profile route",
+			in:      identityInputs{profile: "tenant_a", profileSrc: SourceEnvProfile, direct: pa("env", "cli_a"), directKeys: []string{envvars.CliAppID, envvars.CliAppSecret}, config: tenantA},
+			route:   routeProfile,
+			source:  SourceEnvProfile,
+			matched: true,
+		},
+		{
+			name:    "APP_ID-only block matching the profile yields profile route",
+			in:      identityInputs{profile: "tenant_a", profileSrc: SourceFlagProfile, directBlock: appIDOnlyBlock("cli_a"), directKeys: []string{envvars.CliAppID}, config: tenantA},
+			route:   routeProfile,
+			source:  SourceFlagProfile,
+			matched: true,
+		},
+		{
+			name:    "APP_ID-only block mismatching the profile is a hard conflict",
+			in:      identityInputs{profile: "tenant_a", profileSrc: SourceFlagProfile, directBlock: appIDOnlyBlock("cli_x"), directKeys: []string{envvars.CliAppID}, config: tenantA},
+			subtype: errs.SubtypeProfileAppCredentialConflict,
+		},
+		{
+			name:    "UAT-only block with a valid profile keeps the repair error",
+			in:      identityInputs{profile: "tenant_a", profileSrc: SourceFlagProfile, directBlock: uatOnlyBlock(), config: tenantA},
+			subtype: errs.SubtypeAppCredentialIncomplete,
+		},
+		{
+			name:    "block without profile is app_credential_incomplete",
+			in:      identityInputs{directBlock: appIDOnlyBlock("cli_a"), directKeys: []string{envvars.CliAppID}},
+			subtype: errs.SubtypeAppCredentialIncomplete,
+		},
+		{
+			name:   "complete direct env without profile wins",
+			in:     identityInputs{direct: pa("env", "cli_env"), directKeys: []string{envvars.CliAppID, envvars.CliAppSecret}},
+			route:  routeDirectEnv,
+			source: SourceEnvAppID,
+		},
+		{
+			name:    "malformed config is not masked as profile_not_found",
+			in:      identityInputs{profile: "tenant_a", profileSrc: SourceFlagProfile, configErr: invalidConfigErr},
+			subtype: errs.SubtypeInvalidConfig,
+		},
+		{
+			name:    "absent config degrades to profile_not_found",
+			in:      identityInputs{profile: "ghost", profileSrc: SourceEnvProfile, configErr: notConfiguredErr},
+			subtype: errs.SubtypeProfileNotFound,
+		},
+		{
+			name:    "profile missing from a valid config is profile_not_found even with incomplete env",
+			in:      identityInputs{profile: "ghost", profileSrc: SourceEnvProfile, directBlock: appIDOnlyBlock("cli_a"), directKeys: []string{envvars.CliAppID}, config: tenantA},
+			subtype: errs.SubtypeProfileNotFound,
+		},
+		{
+			name:   "config default reports currentApp",
+			in:     identityInputs{config: tenantA},
+			route:  routeConfigDefault,
+			source: SourceConfigCurrentApp,
+		},
+		{
+			name:   "config default without currentApp reports firstApp",
+			in:     identityInputs{config: noCurrent},
+			route:  routeConfigDefault,
+			source: SourceConfigFirstApp,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			d, err := decideIdentity(tc.in)
+			if tc.subtype != "" {
+				if err == nil {
+					t.Fatalf("decideIdentity = %+v, want error subtype %q", d, tc.subtype)
+				}
+				prob, ok := errs.ProblemOf(err)
+				if !ok || prob.Subtype != tc.subtype {
+					t.Fatalf("error = %v, want subtype %q", err, tc.subtype)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("decideIdentity: %v", err)
+			}
+			if d.route != tc.route {
+				t.Errorf("route = %d, want %d", d.route, tc.route)
+			}
+			if d.selection.Source != tc.source {
+				t.Errorf("source = %q, want %q", d.selection.Source, tc.source)
+			}
+			if d.selection.DirectCredentialEnv.Matched != tc.matched {
+				t.Errorf("matched = %v, want %v", d.selection.DirectCredentialEnv.Matched, tc.matched)
+			}
+		})
+	}
+}
diff --git a/internal/credential/default_provider.go b/internal/credential/default_provider.go
index d7401b62ed..d927917fe1 100644
--- a/internal/credential/default_provider.go
+++ b/internal/credential/default_provider.go
@@ -74,9 +74,13 @@ func NewDefaultAccountProvider(kc func() keychain.KeychainAccess, profile string
 
 func (p *DefaultAccountProvider) ResolveAccount(ctx context.Context) (*Account, error) {
 	// Load config once — used for both credentials and strict mode.
-	multi, err := core.LoadMultiAppConfig()
+	// LoadOrNotConfigured distinguishes an absent config (→ not_configured)
+	// from a malformed/unreadable one (→ invalid_config with cause), so a
+	// broken config is never masked as "run config init" — matching the
+	// explicit-profile path in doResolveAccount.
+	multi, err := core.LoadOrNotConfigured()
 	if err != nil {
-		return nil, core.NotConfiguredError()
+		return nil, err
 	}
 
 	cfg, err := core.ResolveConfigFromMulti(multi, p.keychain(), p.profile)
@@ -116,6 +120,7 @@ type DefaultTokenProvider struct {
 
 	tatOnce   sync.Once
 	tatResult *TokenResult
+	tatAppID  string
 	tatErr    error
 }
 
@@ -126,21 +131,42 @@ func NewDefaultTokenProvider(defaultAcct *DefaultAccountProvider, httpClient fun
 func (p *DefaultTokenProvider) ResolveToken(ctx context.Context, req TokenSpec) (*TokenResult, error) {
 	switch req.Type {
 	case TokenTypeUAT:
-		return p.resolveUAT(ctx)
+		return p.resolveUAT(ctx, req)
 	case TokenTypeTAT:
-		return p.resolveTAT(ctx)
+		return p.resolveTAT(ctx, req)
 	default:
 		return nil, fmt.Errorf("unsupported token type: %s", req.Type)
 	}
 }
 
+// checkTokenAppID refuses to hand out a token for a different app than the
+// caller resolved. The token provider re-reads the config, so a concurrent
+// profile edit between account resolution and token resolution could otherwise
+// cross tokens between apps. TokenSpec.AppID is REQUIRED here: an empty value
+// would silently disable the guarantee, so it is rejected rather than skipped.
+func checkTokenAppID(req TokenSpec, resolvedAppID string) error {
+	if req.AppID == "" {
+		return errs.NewInternalError(errs.SubtypeUnknown,
+			"TokenSpec.AppID is required for %s token resolution", req.Type)
+	}
+	if req.AppID == resolvedAppID {
+		return nil
+	}
+	return errs.NewInternalError(errs.SubtypeUnknown,
+		"config changed during resolution: token requested for app %q but the saved profile now resolves to a different app", req.AppID).
+		WithHint("retry the command.")
+}
+
 // resolveUAT resolves a user access token. Not cached (unlike TAT) because UAT
 // may be refreshed between calls and GetValidAccessToken handles its own caching.
-func (p *DefaultTokenProvider) resolveUAT(ctx context.Context) (*TokenResult, error) {
+func (p *DefaultTokenProvider) resolveUAT(ctx context.Context, req TokenSpec) (*TokenResult, error) {
 	acct, err := p.defaultAcct.ResolveAccount(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if err := checkTokenAppID(req, acct.AppID); err != nil {
+		return nil, err
+	}
 	httpClient, err := p.httpClient()
 	if err != nil {
 		return nil, err
@@ -157,20 +183,36 @@ func (p *DefaultTokenProvider) resolveUAT(ctx context.Context) (*TokenResult, er
 	return &TokenResult{Token: token, Scopes: scopes}, nil
 }
 
-// resolveTAT resolves a tenant access token. The result is cached after the first
-// call via sync.Once — only the context from the first call is used.
-func (p *DefaultTokenProvider) resolveTAT(ctx context.Context) (*TokenResult, error) {
-	p.tatOnce.Do(func() {
-		p.tatResult, p.tatErr = p.doResolveTAT(ctx)
-	})
-	return p.tatResult, p.tatErr
-}
-
-func (p *DefaultTokenProvider) doResolveTAT(ctx context.Context) (*TokenResult, error) {
+// resolveTAT resolves a tenant access token. The result is cached after the
+// first mint via sync.Once — only the context from that call is used.
+//
+// The account is resolved and checked against the request BEFORE any token
+// work: a mismatched request must not trigger a token mint (network call,
+// quota, audit trail) for the wrong app. The cached result is additionally
+// re-checked on every hit, so a token minted for one app is never served to
+// a request that resolved another.
+func (p *DefaultTokenProvider) resolveTAT(ctx context.Context, req TokenSpec) (*TokenResult, error) {
 	acct, err := p.defaultAcct.ResolveAccount(ctx)
 	if err != nil {
 		return nil, err
 	}
+	if err := checkTokenAppID(req, acct.AppID); err != nil {
+		return nil, err
+	}
+	p.tatOnce.Do(func() {
+		p.tatResult, p.tatErr = p.doResolveTAT(ctx, acct)
+		p.tatAppID = acct.AppID
+	})
+	if p.tatErr != nil {
+		return nil, p.tatErr
+	}
+	if err := checkTokenAppID(req, p.tatAppID); err != nil {
+		return nil, err
+	}
+	return p.tatResult, nil
+}
+
+func (p *DefaultTokenProvider) doResolveTAT(ctx context.Context, acct *Account) (*TokenResult, error) {
 	httpClient, err := p.httpClient()
 	if err != nil {
 		return nil, err
diff --git a/internal/credential/default_provider_test.go b/internal/credential/default_provider_test.go
index 057f1dba80..06b8332461 100644
--- a/internal/credential/default_provider_test.go
+++ b/internal/credential/default_provider_test.go
@@ -4,10 +4,15 @@
 package credential
 
 import (
+	"context"
 	"errors"
+	"io"
+	"net/http"
+	"strings"
 	"testing"
 
 	"github.com/larksuite/cli/errs"
+	"github.com/larksuite/cli/internal/core"
 )
 
 func TestDefaultTokenProvider_Dispatches(t *testing.T) {
@@ -92,3 +97,136 @@ func TestClassifyTATResponseCode_CodeZeroOtherError_StillTyped(t *testing.T) {
 		t.Fatalf("code-0 invalid_scope must not be a ConfigError, got %T", err)
 	}
 }
+
+func TestCheckTokenAppID(t *testing.T) {
+	if err := checkTokenAppID(TokenSpec{Type: TokenTypeUAT}, "cli_a"); err == nil {
+		t.Fatal("empty requested app must be rejected: it would silently disable the guarantee")
+	}
+	if err := checkTokenAppID(TokenSpec{AppID: "cli_a"}, "cli_a"); err != nil {
+		t.Fatalf("matching app must pass: %v", err)
+	}
+	err := checkTokenAppID(TokenSpec{AppID: "cli_a"}, "cli_b")
+	if err == nil {
+		t.Fatal("mismatched app must be refused")
+	}
+	var ie *errs.InternalError
+	if !errors.As(err, &ie) {
+		t.Fatalf("error type = %T, want *errs.InternalError", err)
+	}
+}
+
+// REAL-path regression for review F2: the token provider re-reads the config,
+// so a profile edit between account resolution and token resolution must not
+// hand a token minted for the new app to a caller that resolved the old one.
+// Uses the real DefaultAccountProvider + DefaultTokenProvider; the HTTP stub
+// makes the network step unreachable, so reaching it proves the app check ran
+// and passed first.
+func TestDefaultTokenProvider_RefusesTokenAfterConfigSwap(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	writeCfg := func(appID string) {
+		t.Helper()
+		multi := &core.MultiAppConfig{CurrentApp: "tenant_a", Apps: []core.AppConfig{{
+			Name: "tenant_a", AppId: appID, AppSecret: core.PlainSecret("your-secret"), Brand: core.BrandFeishu,
+		}}}
+		if err := core.SaveMultiAppConfig(multi); err != nil {
+			t.Fatalf("SaveMultiAppConfig: %v", err)
+		}
+	}
+	writeCfg("cli_a")
+
+	httpSentinel := errors.New("http client sentinel: unreachable in test")
+	tp := NewDefaultTokenProvider(
+		NewDefaultAccountProvider(nil, "tenant_a"),
+		func() (*http.Client, error) { return nil, httpSentinel },
+		nil,
+	)
+
+	// Matching app: the consistency check passes and resolution proceeds to
+	// the (stubbed) HTTP step.
+	_, err := tp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "cli_a"})
+	if !errors.Is(err, httpSentinel) {
+		t.Fatalf("err = %v, want the HTTP sentinel (check must pass for a matching app)", err)
+	}
+
+	// The profile now resolves to a different app: the token request that was
+	// arbitrated for cli_a must be refused before any token work happens.
+	writeCfg("cli_b")
+	_, err = tp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeUAT, AppID: "cli_a"})
+	if err == nil || !strings.Contains(err.Error(), "config changed during resolution") {
+		t.Fatalf("err = %v, want config-changed refusal", err)
+	}
+}
+
+// F1 regression: a TAT request for a mismatched app must be refused BEFORE
+// any token work starts — no HTTP client construction, no mint, no cache —
+// otherwise the CLI mints (and caches) a token for the wrong app and only
+// then refuses to return it, leaving auth audit/quota side effects behind.
+func TestDefaultTokenProvider_TATChecksAppBeforeAnyTokenWork(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	multi := &core.MultiAppConfig{CurrentApp: "tenant_a", Apps: []core.AppConfig{{
+		Name: "tenant_a", AppId: "cli_b", AppSecret: core.PlainSecret("your-secret"), Brand: core.BrandFeishu,
+	}}}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	httpCalled := false
+	tp := NewDefaultTokenProvider(
+		NewDefaultAccountProvider(nil, "tenant_a"),
+		func() (*http.Client, error) { httpCalled = true; return nil, errors.New("http sentinel") },
+		nil,
+	)
+
+	// The profile resolves to cli_b, but the caller arbitrated cli_a.
+	_, err := tp.ResolveToken(context.Background(), TokenSpec{Type: TokenTypeTAT, AppID: "cli_a"})
+	if err == nil || !strings.Contains(err.Error(), "config changed during resolution") {
+		t.Fatalf("err = %v, want config-changed refusal", err)
+	}
+	if httpCalled {
+		t.Fatal("token work started for a mismatched app: the check must run before any HTTP client is built")
+	}
+}
+
+// countingTATTripper serves a canned successful TAT response and counts calls.
+type countingTATTripper struct{ calls int }
+
+func (c *countingTATTripper) RoundTrip(*http.Request) (*http.Response, error) {
+	c.calls++
+	return &http.Response{
+		StatusCode: http.StatusOK,
+		Body:       io.NopCloser(strings.NewReader(`{"code":0,"access_token":"your-access-token"}`)),
+		Header:     http.Header{"Content-Type": []string{"application/json"}},
+	}, nil
+}
+
+// TAT happy path: the first request mints the token over HTTP, the second is
+// served from the sync.Once cache without another HTTP call.
+func TestDefaultTokenProvider_TATSuccessAndCacheHit(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	multi := &core.MultiAppConfig{CurrentApp: "tenant_a", Apps: []core.AppConfig{{
+		Name: "tenant_a", AppId: "cli_a", AppSecret: core.PlainSecret("your-secret"), Brand: core.BrandFeishu,
+	}}}
+	if err := core.SaveMultiAppConfig(multi); err != nil {
+		t.Fatalf("SaveMultiAppConfig: %v", err)
+	}
+
+	tripper := &countingTATTripper{}
+	tp := NewDefaultTokenProvider(
+		NewDefaultAccountProvider(nil, "tenant_a"),
+		func() (*http.Client, error) { return &http.Client{Transport: tripper}, nil },
+		nil,
+	)
+
+	req := TokenSpec{Type: TokenTypeTAT, AppID: "cli_a"}
+	first, err := tp.ResolveToken(context.Background(), req)
+	if err != nil || first.Token != "your-access-token" {
+		t.Fatalf("first resolve = %+v, %v; want minted token", first, err)
+	}
+	second, err := tp.ResolveToken(context.Background(), req)
+	if err != nil || second.Token != "your-access-token" {
+		t.Fatalf("second resolve = %+v, %v; want cached token", second, err)
+	}
+	if tripper.calls != 1 {
+		t.Fatalf("HTTP calls = %d, want exactly 1 (second resolve must hit the cache)", tripper.calls)
+	}
+}
diff --git a/internal/credential/identity_selection.go b/internal/credential/identity_selection.go
new file mode 100644
index 0000000000..bba484fc9c
--- /dev/null
+++ b/internal/credential/identity_selection.go
@@ -0,0 +1,54 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package credential
+
+// CredentialSourceKind is the wire-stable App/credential selection source.
+type CredentialSourceKind string
+
+const (
+	SourceFlagProfile      CredentialSourceKind = "flag:--profile"
+	SourceEnvProfile       CredentialSourceKind = "env:LARKSUITE_CLI_PROFILE"
+	SourceEnvAppID         CredentialSourceKind = "env:LARKSUITE_CLI_APP_ID"
+	SourceConfigCurrentApp CredentialSourceKind = "config:currentApp"
+	SourceConfigFirstApp   CredentialSourceKind = "config:firstApp"
+
+	// SourceExtensionPrefix prefixes the name of a managed extension provider
+	// that won selection outright (e.g. "extension:sidecar"). With it, an
+	// empty Source is left with exactly one meaning: not resolved.
+	SourceExtensionPrefix CredentialSourceKind = "extension:"
+)
+
+// SourceExtension reports the selection source for a managed extension
+// provider by name.
+func SourceExtension(name string) CredentialSourceKind {
+	return SourceExtensionPrefix + CredentialSourceKind(name)
+}
+
+// DirectCredentialEnv describes the state of direct app credential env vars.
+// It never carries a secret value — only names and the non-sensitive app_id.
+type DirectCredentialEnv struct {
+	Present              bool     `json:"present"`
+	Keys                 []string `json:"keys,omitempty"`
+	AppID                string   `json:"appId,omitempty"`
+	Matched              bool     `json:"matched,omitempty"`
+	ConflictsWithProfile bool     `json:"conflictsWithProfile,omitempty"`
+}
+
+// IdentitySelection is the explainable result of credential selection.
+// It carries NO secret value.
+type IdentitySelection struct {
+	Source              CredentialSourceKind
+	DirectCredentialEnv DirectCredentialEnv
+}
+
+// Explicit reports whether the identity was actively specified by the
+// user/agent (flag or env), which governs no-fallback behavior.
+func (s IdentitySelection) Explicit() bool {
+	switch s.Source {
+	case SourceFlagProfile, SourceEnvProfile, SourceEnvAppID:
+		return true
+	default:
+		return false
+	}
+}
diff --git a/internal/credential/identity_selection_test.go b/internal/credential/identity_selection_test.go
new file mode 100644
index 0000000000..326e8753f5
--- /dev/null
+++ b/internal/credential/identity_selection_test.go
@@ -0,0 +1,25 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package credential
+
+import "testing"
+
+func TestIdentitySelectionExplicit(t *testing.T) {
+	cases := []struct {
+		src      CredentialSourceKind
+		explicit bool
+	}{
+		{SourceFlagProfile, true},
+		{SourceEnvProfile, true},
+		{SourceEnvAppID, true},
+		{SourceConfigCurrentApp, false},
+		{SourceConfigFirstApp, false},
+	}
+	for _, c := range cases {
+		sel := IdentitySelection{Source: c.src}
+		if sel.Explicit() != c.explicit {
+			t.Errorf("source %q: Explicit()=%v want %v", c.src, sel.Explicit(), c.explicit)
+		}
+	}
+}
diff --git a/internal/credential/integration_test.go b/internal/credential/integration_test.go
index de173d1948..531e1e0483 100644
--- a/internal/credential/integration_test.go
+++ b/internal/credential/integration_test.go
@@ -52,6 +52,24 @@ func TestFullChain_EnvWins(t *testing.T) {
 	}
 }
 
+func TestFullChain_EnvRejectsDifferentApp(t *testing.T) {
+	t.Setenv(envvars.CliAppID, "env_app")
+	t.Setenv(envvars.CliAppSecret, "env_secret")
+	t.Setenv(envvars.CliUserAccessToken, "env_uat")
+
+	cp := credential.NewCredentialProvider(
+		[]extcred.Provider{&envprovider.Provider{}},
+		nil, nil, nil,
+	)
+
+	_, err := cp.ResolveToken(context.Background(), credential.TokenSpec{
+		Type: credential.TokenTypeUAT, AppID: "other_app",
+	})
+	if err == nil {
+		t.Fatal("ResolveToken() error = nil, want app binding error")
+	}
+}
+
 func TestFullChain_Fallthrough(t *testing.T) {
 	// env provider returns nil (no env vars set), falls through to default token
 	ep := &envprovider.Provider{}
@@ -59,7 +77,8 @@ func TestFullChain_Fallthrough(t *testing.T) {
 
 	cp := credential.NewCredentialProvider(
 		[]extcred.Provider{ep},
-		nil, mock, nil,
+		&mockDefaultAccountProvider{account: &credential.Account{AppID: "app1"}},
+		mock, nil,
 	)
 	result, err := cp.ResolveToken(context.Background(), credential.TokenSpec{
 		Type: credential.TokenTypeUAT, AppID: "app1",
@@ -72,6 +91,14 @@ func TestFullChain_Fallthrough(t *testing.T) {
 	}
 }
 
+type mockDefaultAccountProvider struct {
+	account *credential.Account
+}
+
+func (m *mockDefaultAccountProvider) ResolveAccount(context.Context) (*credential.Account, error) {
+	return m.account, nil
+}
+
 type mockDefaultTokenProvider struct {
 	token  string
 	scopes string
diff --git a/internal/envvars/envvars.go b/internal/envvars/envvars.go
index 36b60e42d5..6d40bc5290 100644
--- a/internal/envvars/envvars.go
+++ b/internal/envvars/envvars.go
@@ -21,6 +21,7 @@ const (
 
 	CliAgentName  = "LARKSUITE_CLI_AGENT_NAME"
 	CliAgentTrace = "LARKSUITE_CLI_AGENT_TRACE"
+	CliProfile    = "LARKSUITE_CLI_PROFILE"
 
 	CliProxyEnable  = "LARKSUITE_CLI_PROXY_ENABLE"
 	CliProxyAddress = "LARKSUITE_CLI_PROXY_ADDRESS"
diff --git a/shortcuts/common/runner_scope_test.go b/shortcuts/common/runner_scope_test.go
index c3313eaf43..fa1f217a1e 100644
--- a/shortcuts/common/runner_scope_test.go
+++ b/shortcuts/common/runner_scope_test.go
@@ -25,6 +25,18 @@ func (r *scopeCheckTokenResolver) ResolveToken(ctx context.Context, req credenti
 	return r.result, r.err
 }
 
+type scopeCheckAccountResolver struct {
+	appID string
+}
+
+func (r scopeCheckAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID}, nil
+}
+
+func newScopeCheckCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, scopeCheckAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 // TestEnhancePermissionError_TypedPermissionErrorRouted pins typed routing:
 // an *errs.PermissionError gets enhanced regardless of its Message text,
 // decoupling this helper from canonical-message rewrites that would
@@ -106,7 +118,7 @@ func TestEnhancePermissionError_PermissionErrorGetsScopeHint(t *testing.T) {
 
 func TestCheckShortcutScopes_PropagatesContextCancellation(t *testing.T) {
 	f := &cmdutil.Factory{
-		Credential: credential.NewCredentialProvider(nil, nil, &scopeCheckTokenResolver{err: context.Canceled}, nil),
+		Credential: newScopeCheckCredentialProvider("app-1", &scopeCheckTokenResolver{err: context.Canceled}),
 	}
 
 	err := checkShortcutScopes(f, context.Background(), core.AsUser, &core.CliConfig{AppID: "app-1"}, []string{"im:message:read"})
@@ -124,9 +136,9 @@ func TestCheckShortcutScopes_PropagatesContextCancellation(t *testing.T) {
 // command for human consumers.
 func TestCheckShortcutScopes_ReturnsTypedPermissionError(t *testing.T) {
 	f := &cmdutil.Factory{
-		Credential: credential.NewCredentialProvider(nil, nil, &scopeCheckTokenResolver{
+		Credential: newScopeCheckCredentialProvider("app-1", &scopeCheckTokenResolver{
 			result: &credential.TokenResult{Token: "t", Scopes: "im:message:read calendar:calendar:read"},
-		}, nil),
+		}),
 	}
 
 	required := []string{"im:message:read", "drive:drive:read", "docx:document:read"}
@@ -168,7 +180,7 @@ func TestCheckShortcutScopes_ReturnsTypedPermissionError(t *testing.T) {
 
 func TestCheckShortcutScopes_IgnoresNonContextTokenErrors(t *testing.T) {
 	f := &cmdutil.Factory{
-		Credential: credential.NewCredentialProvider(nil, nil, &scopeCheckTokenResolver{err: errors.New("token cache unavailable")}, nil),
+		Credential: newScopeCheckCredentialProvider("app-1", &scopeCheckTokenResolver{err: errors.New("token cache unavailable")}),
 	}
 
 	err := checkShortcutScopes(f, context.Background(), core.AsUser, &core.CliConfig{AppID: "app-1"}, []string{"im:message:read"})
diff --git a/shortcuts/drive/drive_status_test.go b/shortcuts/drive/drive_status_test.go
index d00498460b..9a504397fb 100644
--- a/shortcuts/drive/drive_status_test.go
+++ b/shortcuts/drive/drive_status_test.go
@@ -33,6 +33,18 @@ func (r *driveStatusScopedTokenResolver) ResolveToken(ctx context.Context, req c
 	return &credential.TokenResult{Token: "test-token", Scopes: r.scopes}, nil
 }
 
+type driveTestAccountResolver struct {
+	appID string
+}
+
+func (r driveTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID}, nil
+}
+
+func newDriveTestCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, driveTestAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 // TestDriveStatusCategorizesByHash exercises the four-bucket classification
 // against a real walk of the temp dir and a mocked Drive listing.
 func TestDriveStatusCategorizesByHash(t *testing.T) {
@@ -308,7 +320,7 @@ func TestDriveStatusQuickMarksUntrustedTimestampAsModified(t *testing.T) {
 // requiring drive:file:download even after quick mode made download optional.
 func TestDriveStatusExactRejectsMissingDownloadScope(t *testing.T) {
 	f, _, _, _ := cmdutil.TestFactory(t, driveTestConfig())
-	f.Credential = credential.NewCredentialProvider(nil, nil, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly"}, nil)
+	f.Credential = newDriveTestCredentialProvider(driveTestConfig().AppID, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly"})
 
 	tmpDir := t.TempDir()
 	withDriveWorkingDir(t, tmpDir)
@@ -357,7 +369,7 @@ func TestDriveStatusExactRejectsMissingDownloadScope(t *testing.T) {
 // blocked on the exact-mode download scope precheck.
 func TestDriveStatusQuickAcceptsMissingDownloadScope(t *testing.T) {
 	f, stdout, _, reg := cmdutil.TestFactory(t, driveTestConfig())
-	f.Credential = credential.NewCredentialProvider(nil, nil, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly"}, nil)
+	f.Credential = newDriveTestCredentialProvider(driveTestConfig().AppID, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly"})
 
 	tmpDir := t.TempDir()
 	withDriveWorkingDir(t, tmpDir)
diff --git a/shortcuts/drive/drive_sync_test.go b/shortcuts/drive/drive_sync_test.go
index 70104a2f37..0faf591b83 100644
--- a/shortcuts/drive/drive_sync_test.go
+++ b/shortcuts/drive/drive_sync_test.go
@@ -22,7 +22,6 @@ import (
 	"github.com/larksuite/cli/extension/fileio"
 	"github.com/larksuite/cli/internal/cmdutil"
 	"github.com/larksuite/cli/internal/core"
-	"github.com/larksuite/cli/internal/credential"
 	"github.com/larksuite/cli/internal/httpmock"
 	"github.com/larksuite/cli/internal/output"
 	"github.com/larksuite/cli/shortcuts/common"
@@ -1593,7 +1592,7 @@ func TestDriveSyncAskConflictEOFDuringPlanningPreventsAnyWrites(t *testing.T) {
 
 func TestDriveSyncDryRunQuickAcceptsMetadataOnlyScope(t *testing.T) {
 	f, stdout, _, _ := cmdutil.TestFactory(t, driveTestConfig())
-	f.Credential = credential.NewCredentialProvider(nil, nil, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly"}, nil)
+	f.Credential = newDriveTestCredentialProvider(driveTestConfig().AppID, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly"})
 
 	tmpDir := t.TempDir()
 	withDriveWorkingDir(t, tmpDir)
@@ -1622,7 +1621,7 @@ func TestDriveSyncPreflightsActionScopesBeforeListing(t *testing.T) {
 		AppID: "drive-sync-download-scope-only", AppSecret: "test-secret", Brand: core.BrandFeishu,
 	}
 	f, stdout, _, _ := cmdutil.TestFactory(t, syncTestConfig)
-	f.Credential = credential.NewCredentialProvider(nil, nil, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly drive:file:download"}, nil)
+	f.Credential = newDriveTestCredentialProvider(syncTestConfig.AppID, &driveStatusScopedTokenResolver{scopes: "drive:drive.metadata:readonly drive:file:download"})
 
 	tmpDir := t.TempDir()
 	withDriveWorkingDir(t, tmpDir)
diff --git a/shortcuts/drive/drive_task_result_test.go b/shortcuts/drive/drive_task_result_test.go
index 99a4ef7c2c..5f36920d90 100644
--- a/shortcuts/drive/drive_task_result_test.go
+++ b/shortcuts/drive/drive_task_result_test.go
@@ -329,7 +329,7 @@ func newDriveTaskResultRuntimeWithScopes(t *testing.T, as core.Identity, scopes
 
 	cfg := driveTestConfig()
 	factory, _, _, _ := cmdutil.TestFactory(t, cfg)
-	factory.Credential = credential.NewCredentialProvider(nil, nil, &mockDriveTaskResultTokenResolver{scopes: scopes}, nil)
+	factory.Credential = newDriveTestCredentialProvider(cfg.AppID, &mockDriveTaskResultTokenResolver{scopes: scopes})
 
 	runtime := common.TestNewRuntimeContextWithIdentity(&cobra.Command{Use: "drive +task_result"}, cfg, as)
 	runtime.Factory = factory
@@ -919,7 +919,7 @@ func TestValidateDriveTaskResultScopesPropagatesContextCancellation(t *testing.T
 
 	cfg := driveTestConfig()
 	factory, _, _, _ := cmdutil.TestFactory(t, cfg)
-	factory.Credential = credential.NewCredentialProvider(nil, nil, cancelingTokenResolver{}, nil)
+	factory.Credential = newDriveTestCredentialProvider(cfg.AppID, cancelingTokenResolver{})
 
 	runtime := common.TestNewRuntimeContextWithIdentity(&cobra.Command{Use: "drive +task_result"}, cfg, core.AsUser)
 	runtime.Factory = factory
diff --git a/shortcuts/im/convert_lib/runtime_test.go b/shortcuts/im/convert_lib/runtime_test.go
index 5ab8ac154c..fac7a6e0af 100644
--- a/shortcuts/im/convert_lib/runtime_test.go
+++ b/shortcuts/im/convert_lib/runtime_test.go
@@ -27,6 +27,14 @@ func (s *staticConvertlibTokenResolver) ResolveToken(_ context.Context, _ creden
 	return &credential.TokenResult{Token: "test-token"}, nil
 }
 
+type convertlibTestAccountResolver struct {
+	appID string
+}
+
+func (r convertlibTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID}, nil
+}
+
 type convertlibRoundTripFunc func(*http.Request) (*http.Response, error)
 
 func (f convertlibRoundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) {
@@ -68,7 +76,12 @@ func newBotConvertlibRuntime(t *testing.T, rt http.RoundTripper) *common.Runtime
 		AppSecret: "test-secret",
 		Brand:     core.BrandFeishu,
 	}
-	testCred := credential.NewCredentialProvider(nil, nil, &staticConvertlibTokenResolver{}, nil)
+	testCred := credential.NewCredentialProvider(
+		nil,
+		convertlibTestAccountResolver{appID: cfg.AppID},
+		&staticConvertlibTokenResolver{},
+		nil,
+	)
 	runtime := &common.RuntimeContext{
 		Config: cfg,
 		Factory: &cmdutil.Factory{
diff --git a/shortcuts/im/helpers_network_test.go b/shortcuts/im/helpers_network_test.go
index 9d75fcf62a..6f992e1c42 100644
--- a/shortcuts/im/helpers_network_test.go
+++ b/shortcuts/im/helpers_network_test.go
@@ -37,6 +37,18 @@ func (s *staticShortcutTokenResolver) ResolveToken(_ context.Context, _ credenti
 	return &credential.TokenResult{Token: "tenant-token"}, nil
 }
 
+type imTestAccountResolver struct {
+	appID string
+}
+
+func (r imTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID}, nil
+}
+
+func newIMTestCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, imTestAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 type shortcutRoundTripFunc func(*http.Request) (*http.Response, error)
 
 func (f shortcutRoundTripFunc) RoundTrip(req *http.Request) (*http.Response, error) {
@@ -90,7 +102,7 @@ func newBotShortcutRuntime(t *testing.T, rt http.RoundTripper) *common.RuntimeCo
 		AppSecret: "test-secret",
 		Brand:     core.BrandFeishu,
 	}
-	testCred := credential.NewCredentialProvider(nil, nil, &staticShortcutTokenResolver{}, nil)
+	testCred := newIMTestCredentialProvider(cfg.AppID, &staticShortcutTokenResolver{})
 	runtime := &common.RuntimeContext{
 		Config: cfg,
 		Factory: &cmdutil.Factory{
diff --git a/shortcuts/im/im_flag_test.go b/shortcuts/im/im_flag_test.go
index d370c4cde6..f1af6dd1ff 100644
--- a/shortcuts/im/im_flag_test.go
+++ b/shortcuts/im/im_flag_test.go
@@ -288,12 +288,12 @@ func (r errorTokenResolver) ResolveToken(_ context.Context, _ credential.TokenSp
 
 func setRuntimeScopes(t *testing.T, rt *common.RuntimeContext, scopes string) {
 	t.Helper()
-	rt.Factory.Credential = credential.NewCredentialProvider(nil, nil, scopedTokenResolver{scopes: scopes}, nil)
+	rt.Factory.Credential = newIMTestCredentialProvider(rt.Config.AppID, scopedTokenResolver{scopes: scopes})
 }
 
 func setRuntimeTokenError(t *testing.T, rt *common.RuntimeContext, err error) {
 	t.Helper()
-	rt.Factory.Credential = credential.NewCredentialProvider(nil, nil, errorTokenResolver{err: err}, nil)
+	rt.Factory.Credential = newIMTestCredentialProvider(rt.Config.AppID, errorTokenResolver{err: err})
 }
 
 func TestFlagMessageID(t *testing.T) {
diff --git a/shortcuts/wiki/wiki_delete_test.go b/shortcuts/wiki/wiki_delete_test.go
index b2772884ec..4bdcfec33b 100644
--- a/shortcuts/wiki/wiki_delete_test.go
+++ b/shortcuts/wiki/wiki_delete_test.go
@@ -16,7 +16,6 @@ import (
 	"github.com/larksuite/cli/errs"
 	"github.com/larksuite/cli/internal/cmdutil"
 	"github.com/larksuite/cli/internal/core"
-	"github.com/larksuite/cli/internal/credential"
 	"github.com/larksuite/cli/internal/errclass"
 	"github.com/larksuite/cli/internal/httpmock"
 	"github.com/larksuite/cli/shortcuts/common"
@@ -79,7 +78,7 @@ func newWikiDeleteSpaceRuntimeWithScopes(t *testing.T, as core.Identity, scopes
 
 	cfg := wikiTestConfig()
 	factory, _, stderr, _ := cmdutil.TestFactory(t, cfg)
-	factory.Credential = credential.NewCredentialProvider(nil, nil, &mockWikiMoveTokenResolver{scopes: scopes}, nil)
+	factory.Credential = newWikiTestCredentialProvider(cfg.AppID, &mockWikiMoveTokenResolver{scopes: scopes})
 
 	runtime := common.TestNewRuntimeContextWithIdentity(&cobra.Command{Use: "wiki +delete-space"}, cfg, as)
 	runtime.Factory = factory
diff --git a/shortcuts/wiki/wiki_move_test.go b/shortcuts/wiki/wiki_move_test.go
index 6d9a7e64f9..bef854cfe2 100644
--- a/shortcuts/wiki/wiki_move_test.go
+++ b/shortcuts/wiki/wiki_move_test.go
@@ -27,6 +27,18 @@ type fakeWikiMoveNodeCall struct {
 	Spec          wikiMoveSpec
 }
 
+type wikiTestAccountResolver struct {
+	appID string
+}
+
+func (r wikiTestAccountResolver) ResolveAccount(context.Context) (*credential.Account, error) {
+	return &credential.Account{AppID: r.appID}, nil
+}
+
+func newWikiTestCredentialProvider(appID string, tokenResolver credential.DefaultTokenResolver) *credential.CredentialProvider {
+	return credential.NewCredentialProvider(nil, wikiTestAccountResolver{appID: appID}, tokenResolver, nil)
+}
+
 type fakeWikiDocsToWikiMoveCall struct {
 	TargetSpaceID string
 	Spec          wikiMoveSpec
@@ -143,7 +155,7 @@ func newWikiMoveRuntimeWithScopes(t *testing.T, as core.Identity, scopes string)
 
 	cfg := wikiTestConfig()
 	factory, _, stderr, _ := cmdutil.TestFactory(t, cfg)
-	factory.Credential = credential.NewCredentialProvider(nil, nil, &mockWikiMoveTokenResolver{scopes: scopes}, nil)
+	factory.Credential = newWikiTestCredentialProvider(cfg.AppID, &mockWikiMoveTokenResolver{scopes: scopes})
 
 	runtime := common.TestNewRuntimeContextWithIdentity(&cobra.Command{Use: "wiki +move"}, cfg, as)
 	runtime.Factory = factory
diff --git a/sidecar/server-demo/handler_test.go b/sidecar/server-demo/handler_test.go
index edd2446fef..834d217a95 100644
--- a/sidecar/server-demo/handler_test.go
+++ b/sidecar/server-demo/handler_test.go
@@ -26,12 +26,13 @@ import (
 
 // fakeExtProvider is a stub extcred.Provider for tests that returns a fixed token.
 type fakeExtProvider struct {
+	appID string
 	token string
 }
 
 func (f *fakeExtProvider) Name() string { return "fake" }
 func (f *fakeExtProvider) ResolveAccount(ctx context.Context) (*extcred.Account, error) {
-	return nil, nil
+	return &extcred.Account{AppID: f.appID}, nil
 }
 func (f *fakeExtProvider) ResolveToken(ctx context.Context, req extcred.TokenSpec) (*extcred.Token, error) {
 	return &extcred.Token{Value: f.token, Source: "fake"}, nil
@@ -381,7 +382,7 @@ func TestProxyHandler_AcceptsAllowedAuthHeaders(t *testing.T) {
 			// Use a handler with a real (fake) credential provider so we can
 			// distinguish auth-header reject (403) from later failures.
 			cred := credential.NewCredentialProvider(
-				[]extcred.Provider{&fakeExtProvider{token: "real-token"}},
+				[]extcred.Provider{&fakeExtProvider{appID: "cli_test", token: "real-token"}},
 				nil, nil, nil,
 			)
 			h := &proxyHandler{
@@ -501,7 +502,7 @@ func TestProxyHandler_StripsClientSuppliedAuthHeaders(t *testing.T) {
 	upstreamHost := strings.TrimPrefix(upstream.URL, "https://")
 
 	cred := credential.NewCredentialProvider(
-		[]extcred.Provider{&fakeExtProvider{token: realToken}},
+		[]extcred.Provider{&fakeExtProvider{appID: "cli_test", token: realToken}},
 		nil, nil, nil,
 	)
 
diff --git a/skills/lark-shared/SKILL.md b/skills/lark-shared/SKILL.md
index 5b1c94e247..5d8ccf531d 100644
--- a/skills/lark-shared/SKILL.md
+++ b/skills/lark-shared/SKILL.md
@@ -1,7 +1,7 @@
 ---
 name: lark-shared
 version: 1.0.0
-description: "Use for lark-cli setup/auth tasks: auth login/status/logout, user vs bot identity, business-domain permissions (--domain, including all/docs/drive), missing scopes, revoking authorization, or handling _notice JSON."
+description: "Use for lark-cli setup/auth tasks: auth login/status/logout, user vs bot identity, business-domain permissions (--domain, including all/docs/drive), missing scopes, revoking authorization, handling _notice JSON, or pinning/clearing a profile/tenant identity for a task or session."
 ---
 
 # lark-cli 共享规则
@@ -32,7 +32,7 @@ lark-cli config init --new
 | 获取全部权限 | `lark-cli auth login --domain all --no-wait --json` |
 | 按业务域授权 | `lark-cli auth login --domain docs --domain drive --no-wait --json`；`--domain` 可重复，也可用逗号分隔 |
 | 指定单个 scope 授权 | `lark-cli auth login --scope "<scope>" --no-wait --json` |
-| 检查当前登录态、是谁登录、token 是否有效 | `lark-cli auth status --json --verify`；回答时引用 `identity`、`verified`、`identities.user.status`、`identities.user.userName`、`identities.user.openId`（用户 open id）、`identities.user.tokenStatus`、`identities.user.scope` |
+| 检查当前登录态、是谁登录、token 是否有效 | 必须运行 `lark-cli auth status --json --verify`；回答时引用 `identity`、`verified`、`identities.user.status`、`identities.user.userName`、`identities.user.openId`（用户 open id）、`identities.user.tokenStatus`、`identities.user.scope` |
 | 快速查看当前身份状态 | `lark-cli whoami`；实际生效的那一个身份 |
 | 退出当前机器的用户登录态 | `lark-cli auth logout --json`；`loggedOut:true` 表示注销成功 |
 | bot 缺少权限 | 不要执行 `auth login`；引导用户在开发者后台开通 bot scope，优先复用错误里的 `console_url` |
@@ -126,6 +126,18 @@ lark-cli auth login --device-code <device_code>
 - **不要在同一轮中展示 URL 后立刻执行 `--device-code`**，这会导致用户看不到 URL
 - **禁止缓存 `verification_url` 或 `device_code`**：每次需要授权时，必须重新执行 `lark-cli auth login --no-wait --json` 生成新的链接。不要将授权链接和 device code 存入上下文供后续复用
 
+## Profile 选择
+
+- 查当前实际生效身份：`whoami --json`
+- 查 OAuth 登录或 token 有效性：`auth status --json --verify`
+- 为 agent 任务指定身份：每条 `lark-cli` 命令都加 `--profile <profile-or-appId>`
+- 为同一 shell 的脚本或批处理指定身份：使用 `LARKSUITE_CLI_PROFILE=<profile-or-appId>`，或 export/unset
+- 清除会话身份并恢复默认：使用 `unset LARKSUITE_CLI_PROFILE`；即使变量未设置，也向用户说明该操作。不要为此使用 `profile use` 或 `profile remove`
+- 查已保存的配置：`config show` 或 `profile list`；它们不表示当前实际生效身份
+- 永久修改默认 profile：`profile use`
+
+profile 不明确时先问用户。除非用户提供了直连凭证，否则不要设置 `LARKSUITE_CLI_APP_ID` 或 `LARKSUITE_CLI_APP_SECRET`。
+
 ## 更新检查
 
 lark-cli 命令执行后，如果检测到新版本，JSON 输出中会包含 `_notice.update` 字段（含 `message`、`command` 等）。