feat(sec): integrate enterprise cli

Replace the embedded bootstrap manifest with a typed OAPI call to
GET /open-apis/security_plugin/v1/sec_cli/manifest, resolving the
download URL per-platform/per-arch against the live release set.
TAT auth flows through the existing credential chain; an x-tt-env
header is injected when LARKSUITE_CLI_X_TT_ENV is set, for BOE
routing.

Drop the standalone `sec install` verb — `sec run --auto-install`
(default on) makes it redundant. Add a persistent --verbose / -v
flag on the sec parent, inherited by every subcommand, that emits
step-by-step trace output on stderr.

bootstrap.json and bootstrap.go remain in-tree as dead code; they
will be removed in a follow-up cleanup.

cmd/build.go

@@ -15,6 +15,7 @@ import (
 	cmdevent "github.com/larksuite/cli/cmd/event"
 	"github.com/larksuite/cli/cmd/profile"
 	"github.com/larksuite/cli/cmd/schema"
+	"github.com/larksuite/cli/cmd/sec"
 	"github.com/larksuite/cli/cmd/service"
 	cmdupdate "github.com/larksuite/cli/cmd/update"
 	_ "github.com/larksuite/cli/events"
@@ -133,6 +134,7 @@ func buildInternal(ctx context.Context, inv cmdutil.InvocationContext, opts ...B
 	rootCmd.AddCommand(completion.NewCmdCompletion(f))
 	rootCmd.AddCommand(cmdupdate.NewCmdUpdate(f))
 	rootCmd.AddCommand(cmdevent.NewCmdEvents(f))
+	rootCmd.AddCommand(sec.NewCmdSec(f))
 	service.RegisterServiceCommandsWithContext(ctx, rootCmd, f)
 	shortcuts.RegisterShortcutsWithContext(ctx, rootCmd, f)
 

cmd/sec/config_init.go

@@ -0,0 +1,251 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"bytes"
+	"context"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strconv"
+	"time"
+
+	"github.com/charmbracelet/huh"
+	"github.com/spf13/cobra"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/output"
+)
+
+// NewCmdSecConfig is the parent for `lark-cli sec config <verb>`. Currently
+// it only carries `init`; future verbs (e.g. `show`, `reset`) plug in here.
+func NewCmdSecConfig(f *cmdutil.Factory) *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "config",
+		Short: "Manage lark-sec-cli daemon configuration",
+	}
+	cmd.AddCommand(NewCmdSecConfigInit(f, nil))
+	return cmd
+}
+
+// ConfigInitOptions holds inputs for `lark-cli sec config init`.
+type ConfigInitOptions struct {
+	Factory   *cmdutil.Factory
+	AppID     string
+	AppSecret string
+	Brand     string
+	Yes       bool // skip the interactive form when all required values are provided
+}
+
+// NewCmdSecConfigInit collects App ID / App Secret / Brand from the user and
+// registers them with the running lark-sec-cli daemon's admin endpoint. The
+// daemon stashes the secret in the OS keychain and switches into sidecar mode
+// for SEC_AUTH credential isolation.
+func NewCmdSecConfigInit(f *cmdutil.Factory, runF func(*ConfigInitOptions) error) *cobra.Command {
+	opts := &ConfigInitOptions{Factory: f}
+	cmd := &cobra.Command{
+		Use:   "init",
+		Short: "Register a Lark App with the running lark-sec-cli daemon",
+		Long: `Register an App ID / App Secret with the lark-sec-cli daemon.
+
+The daemon must already be running (start it with "lark-cli sec run"). The
+registration POSTs to /_sec/api/v1/register-app on the local proxy port,
+HMAC-signed with the daemon's proxy.key.`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if runF != nil {
+				return runF(opts)
+			}
+			return runConfigInit(cmd, opts)
+		},
+	}
+	cmd.Flags().StringVar(&opts.AppID, "app-id", "", "App ID (skips the prompt when set)")
+	cmd.Flags().StringVar(&opts.AppSecret, "app-secret", "", "App Secret (skips the prompt when set)")
+	cmd.Flags().StringVar(&opts.Brand, "brand", "feishu", "feishu or lark")
+	cmd.Flags().BoolVarP(&opts.Yes, "yes", "y", false, "skip the interactive form when all required values are provided")
+	return cmd
+}
+
+// secBridge mirrors what the daemon writes to ~/.lark-cli/sec_config.json.
+// It's the single contract between lark-cli and lark-sec-cli at runtime —
+// we don't reach into lark-sec-cli internals, only what it chooses to publish.
+type secBridge struct {
+	Enable bool   `json:"LARKSUITE_CLI_SEC_ENABLE"`
+	Proxy  string `json:"LARKSUITE_CLI_SEC_PROXY"`
+	CA     string `json:"LARKSUITE_CLI_SEC_CA"`
+	Auth   bool   `json:"LARKSUITE_CLI_SEC_AUTH"`
+}
+
+func runConfigInit(cmd *cobra.Command, opts *ConfigInitOptions) error {
+	errOut := opts.Factory.IOStreams.ErrOut
+	trace := verboseOut(cmd, errOut)
+
+	tracef(trace, "sec config init", "loading daemon bridge from %s/sec_config.json", core.GetConfigDir())
+	bridge, err := loadBridge()
+	if err != nil {
+		return output.ErrWithHint(output.ExitValidation, "sec_bridge_missing",
+			fmt.Sprintf("daemon bridge file unreadable: %v", err),
+			"Start the daemon first: `lark-cli sec run`.")
+	}
+	tracef(trace, "sec config init", "bridge: enable=%t proxy=%s ca=%s auth=%t", bridge.Enable, bridge.Proxy, bridge.CA, bridge.Auth)
+	if !bridge.Enable || bridge.Proxy == "" {
+		return output.ErrWithHint(output.ExitValidation, "sec_not_running",
+			"lark-sec-cli is not advertising an active proxy",
+			"Run `lark-cli sec run` to start it.")
+	}
+
+	// The HMAC key sits next to the CA in the daemon's config dir. Deriving
+	// from the bridge's SEC_CA path keeps lark-cli decoupled from the daemon's
+	// install location — if the daemon ever moves, the bridge follows and we
+	// follow with it.
+	tracef(trace, "sec config init", "reading daemon HMAC key beside %s", bridge.CA)
+	hmacKey, err := readHMACKey(bridge.CA)
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "sec_hmac_key", "read daemon HMAC key: %v", err)
+	}
+
+	if err := promptForMissing(opts); err != nil {
+		return err
+	}
+
+	tracef(trace, "sec config init", "POST %s/_sec/api/v1/register-app app_id=%s brand=%s", bridge.Proxy, opts.AppID, opts.Brand)
+	if err := registerApp(cmd.Context(), bridge.Proxy, hmacKey, opts.AppID, opts.AppSecret, opts.Brand); err != nil {
+		return output.Errorf(output.ExitAPI, "sec_register_app", "register-app: %v", err)
+	}
+
+	output.PrintSuccess(errOut,
+		fmt.Sprintf("registered app %s with lark-sec-cli (%s)", opts.AppID, opts.Brand))
+	return nil
+}
+
+// loadBridge reads the daemon-written sec_config.json from lark-cli's config dir.
+func loadBridge() (*secBridge, error) {
+	path := filepath.Join(core.GetConfigDir(), "sec_config.json")
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	var b secBridge
+	if err := json.Unmarshal(data, &b); err != nil {
+		return nil, fmt.Errorf("parse %s: %w", path, err)
+	}
+	return &b, nil
+}
+
+// readHMACKey returns the daemon's proxy.key bytes. The daemon writes the key
+// hex-encoded (64 ASCII chars); we hex-decode here. If the file is a raw
+// 32-byte blob (older daemon variants), we use it as-is.
+func readHMACKey(caPath string) ([]byte, error) {
+	if caPath == "" {
+		return nil, errors.New("sec_config.json has no LARKSUITE_CLI_SEC_CA — can't locate proxy.key")
+	}
+	keyPath := filepath.Join(filepath.Dir(caPath), "proxy.key")
+	raw, err := os.ReadFile(keyPath)
+	if err != nil {
+		return nil, err
+	}
+	raw = bytes.TrimSpace(raw)
+	if len(raw) == 64 {
+		if decoded, err := hex.DecodeString(string(raw)); err == nil {
+			return decoded, nil
+		}
+	}
+	return raw, nil
+}
+
+// promptForMissing fills in any of AppID / AppSecret / Brand the user didn't
+// provide via flags. --yes refuses to prompt; that's caller error if any are
+// still missing at that point.
+func promptForMissing(opts *ConfigInitOptions) error {
+	if opts.AppID != "" && opts.AppSecret != "" && opts.Brand != "" {
+		return nil
+	}
+	if opts.Yes {
+		return output.ErrValidation("--yes set but missing one of --app-id / --app-secret / --brand")
+	}
+
+	groups := []*huh.Group{}
+	if opts.AppID == "" {
+		groups = append(groups, huh.NewGroup(
+			huh.NewInput().Title("App ID").Placeholder("cli_xxxx").Value(&opts.AppID),
+		))
+	}
+	if opts.AppSecret == "" {
+		groups = append(groups, huh.NewGroup(
+			huh.NewInput().Title("App Secret").EchoMode(huh.EchoModePassword).Value(&opts.AppSecret),
+		))
+	}
+	if opts.Brand == "" {
+		opts.Brand = "feishu"
+		groups = append(groups, huh.NewGroup(
+			huh.NewSelect[string]().Title("Brand").Options(
+				huh.NewOption("Feishu (cn)", "feishu"),
+				huh.NewOption("Lark (intl)", "lark"),
+			).Value(&opts.Brand),
+		))
+	}
+	if len(groups) == 0 {
+		return nil
+	}
+	form := huh.NewForm(groups...).WithTheme(cmdutil.ThemeFeishu())
+	if err := form.Run(); err != nil {
+		if errors.Is(err, huh.ErrUserAborted) {
+			return output.ErrBare(1)
+		}
+		return err
+	}
+	return nil
+}
+
+// registerApp POSTs to /_sec/api/v1/register-app with the daemon's HMAC scheme.
+// Canonical signing input is "method\npath\nsha256hex(body)\ntimestamp", per
+// lark-sec-cli/internal/proxy/admin_handler.go's verifyHMAC.
+func registerApp(ctx context.Context, proxyURL string, hmacKey []byte, appID, appSecret, brand string) error {
+	const path = "/_sec/api/v1/register-app"
+
+	body, err := json.Marshal(map[string]string{
+		"app_id":     appID,
+		"app_secret": appSecret,
+		"brand":      brand,
+	})
+	if err != nil {
+		return err
+	}
+
+	ts := strconv.FormatInt(time.Now().Unix(), 10)
+	bodyHash := sha256.Sum256(body)
+	canonical := http.MethodPost + "\n" + path + "\n" + hex.EncodeToString(bodyHash[:]) + "\n" + ts
+	mac := hmac.New(sha256.New, hmacKey)
+	mac.Write([]byte(canonical))
+	sig := hex.EncodeToString(mac.Sum(nil))
+
+	reqCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
+	defer cancel()
+	req, err := http.NewRequestWithContext(reqCtx, http.MethodPost, proxyURL+path, bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("X-Lark-Admin-Signature", sig)
+	req.Header.Set("X-Lark-Admin-Timestamp", ts)
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(io.LimitReader(resp.Body, 64<<10))
+	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+		return nil
+	}
+	return fmt.Errorf("status %d: %s", resp.StatusCode, string(respBody))
+}

cmd/sec/factory.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"fmt"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+	intsec "github.com/larksuite/cli/internal/sec"
+)
+
+// installer wires up an internal/sec.Installer using the Factory's HTTP client,
+// the default platform paths, and a lazy OAPI-client provider used to fetch
+// the install manifest. APIClientFunc is a method value, not an eager call —
+// commands that short-circuit (or that never install, like sec status / sec
+// stop) avoid decrypting credentials from the keychain. Every cmd/sec
+// subcommand starts here.
+func installer(f *cmdutil.Factory) (*intsec.Installer, *intsec.Paths, error) {
+	paths, err := intsec.DefaultPaths()
+	if err != nil {
+		return nil, nil, fmt.Errorf("resolve sec paths: %w", err)
+	}
+	httpClient, err := f.HttpClient()
+	if err != nil {
+		return nil, nil, fmt.Errorf("resolve http client: %w", err)
+	}
+	return &intsec.Installer{
+		Paths:         paths,
+		HTTPClient:    httpClient,
+		APIClientFunc: f.NewAPIClient,
+	}, paths, nil
+}

cmd/sec/run.go

@@ -0,0 +1,127 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+
+	"github.com/spf13/cobra"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/output"
+	intsec "github.com/larksuite/cli/internal/sec"
+)
+
+// RunOptions holds inputs for `lark-cli sec run`.
+type RunOptions struct {
+	Factory   *cmdutil.Factory
+	ProxyPort int
+	// AutoInstall runs `sec install` first when no binary is recorded.
+	AutoInstall bool
+}
+
+// NewCmdSecRun starts lark-sec-cli as a user-level system service so it
+// persists across logins and gets restarted by the OS supervisor if it
+// crashes. Under the hood it shells out to `lark-sec-cli service enable`,
+// which is the recommended startup path per the lark-sec-cli manual:
+//
+//   - macOS  → user-level launchd plist with KeepAlive=true
+//   - Linux  → user systemd unit with Restart=always
+//   - Windows → registry autostart + a VBS watchdog loop
+//
+// Switching to this from a detached `exec.Command(... Setsid:true)` spawn
+// fixes two latent issues at once: (1) daemon logs survive past lark-cli
+// exit because the service supervisor — not our terminated pipes — owns
+// the daemon's stdout, and (2) the daemon's own self-upgrade module can
+// now fire (it gates on running-under-supervisor).
+func NewCmdSecRun(f *cmdutil.Factory, runF func(*RunOptions) error) *cobra.Command {
+	opts := &RunOptions{Factory: f, AutoInstall: true}
+	cmd := &cobra.Command{
+		Use:   "run",
+		Short: "Enable lark-sec-cli as a user system service (the daemon runs in the background)",
+		Long: `Install lark-sec-cli as a user-level system service so the proxy
+daemon runs automatically, persists across logins, and is restarted by the
+OS if it exits. The daemon writes its own log file (default: under
+~/.lark-sec-cli/logs/daemon.log) so logs persist independently of this
+command.
+
+After enabling, the daemon writes ~/.lark-cli/sec_config.json itself with
+the proxy port and CA path, so subsequent lark-cli runs route through the
+sidecar without any further action.
+
+To stop and remove the service: lark-cli sec stop.`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if runF != nil {
+				return runF(opts)
+			}
+			return runRun(cmd, opts)
+		},
+	}
+	cmd.Flags().IntVar(&opts.ProxyPort, "proxy-port", 0, "force lark-sec-cli to bind this port (default: dynamic)")
+	cmd.Flags().BoolVar(&opts.AutoInstall, "auto-install", true, "bootstrap-install lark-sec-cli first when no binary is recorded")
+	return cmd
+}
+
+func runRun(cmd *cobra.Command, opts *RunOptions) error {
+	ctx := cmd.Context()
+	errOut := opts.Factory.IOStreams.ErrOut
+	trace := verboseOut(cmd, errOut)
+
+	tracef(trace, "sec run", "constructing installer (lazy credentials)")
+	inst, paths, err := installer(opts.Factory)
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "internal", "%v", err)
+	}
+
+	// Make sure we have a binary on disk before asking it to install itself
+	// as a service.
+	tracef(trace, "sec run", "loading state from %s", paths.StateFile())
+	state, err := intsec.LoadState(paths.StateFile())
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "internal", "load sec state: %v", err)
+	}
+	if state == nil {
+		tracef(trace, "sec run", "no install on disk (auto-install=%t)", opts.AutoInstall)
+		if !opts.AutoInstall {
+			return output.ErrWithHint(output.ExitValidation, "sec_not_installed",
+				"lark-sec-cli is not installed",
+				"Re-run `lark-cli sec run` with --auto-install (default on), or remove --auto-install=false.")
+		}
+		state, err = inst.Install(ctx, intsec.InstallOptions{Verbose: trace})
+		if err != nil {
+			return output.Errorf(output.ExitNetwork, "sec_install", "auto-install lark-sec-cli: %v", err)
+		}
+	} else {
+		tracef(trace, "sec run", "existing install: version=%s binary=%s", state.Version, state.BinaryPath)
+	}
+
+	args := []string{"service", "enable"}
+	if opts.ProxyPort > 0 {
+		args = append(args, fmt.Sprintf("--proxy-port=%d", opts.ProxyPort))
+	}
+
+	fmt.Fprintf(errOut, "Running: %s %v\n", state.BinaryPath, args)
+	tracef(trace, "sec run", "shelling out to %s %v", state.BinaryPath, args)
+
+	c := exec.CommandContext(ctx, state.BinaryPath, args...)
+	var stdout, stderr bytes.Buffer
+	c.Stdout = &stdout
+	c.Stderr = &stderr
+	if err := c.Run(); err != nil {
+		return output.Errorf(output.ExitInternal, "sec_service_enable",
+			"`lark-sec-cli service enable` failed: %v\nstderr: %s", err, stderr.String())
+	}
+	tracef(trace, "sec run", "service enable returned ok (%d bytes stdout)", stdout.Len())
+
+	// Forward the installer's stdout to the user — it contains the launchd /
+	// systemd unit name, the registered executable path, and a confirmation
+	// that the supervisor will respawn the daemon on exit. Useful diagnostic
+	// output that's better seen than swallowed.
+	fmt.Fprint(errOut, stdout.String())
+	output.PrintSuccess(errOut,
+		"lark-sec-cli enabled as a user system service. Run `lark-cli sec status` to verify, `lark-cli sec stop` to disable.")
+	return nil
+}

cmd/sec/sec.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+// Package sec exposes the `lark-cli sec` command tree that bootstraps the
+// lark-sec-cli sidecar daemon: install, run, stop, status, and `config init`.
+// The internal/sec package owns the implementation; this package is a thin
+// Cobra wrapper that mirrors the conventions in cmd/auth.
+//
+// After bootstrap install, lark-sec-cli handles its own upgrade lifecycle —
+// lark-cli is not in the update path, which is why there's no `sec update`
+// subcommand here.
+package sec
+
+import (
+	"github.com/spf13/cobra"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+)
+
+// NewCmdSec builds the parent `sec` command and registers all subcommands.
+//
+// The persistent --verbose / -v flag is inherited by every subcommand:
+// `sec run -v`, `sec status -v`, etc. all emit step-by-step trace output to
+// stderr.
+//
+// There is no `sec install` subcommand — `sec run` auto-installs lark-sec-cli
+// if no binary is on disk, so a separate install verb was redundant.
+func NewCmdSec(f *cmdutil.Factory) *cobra.Command {
+	var verbose bool
+	cmd := &cobra.Command{
+		Use:   "sec",
+		Short: "Manage the lark-sec-cli security sidecar (run, status, stop, config)",
+		Long: `Manage the lark-sec-cli security sidecar.
+
+lark-sec-cli is a local HTTPS proxy daemon that intercepts lark-cli's traffic,
+injects BDMS risk-control signatures, and manages credentials via the OS
+keychain. These subcommands handle the runtime lifecycle from lark-cli's side:
+start the daemon (auto-installing on first run), inspect its state, register
+an app with it, and stop it. Updates after the first install are managed by
+lark-sec-cli itself.`,
+	}
+	cmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false,
+		"print step-by-step pipeline output to stderr")
+	cmd.AddCommand(NewCmdSecRun(f, nil))
+	cmd.AddCommand(NewCmdSecStop(f, nil))
+	cmd.AddCommand(NewCmdSecStatus(f, nil))
+	cmd.AddCommand(NewCmdSecConfig(f))
+	return cmd
+}

cmd/sec/sec_test.go

@@ -0,0 +1,38 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/core"
+)
+
+// TestNewCmdSec_HasAllSubcommands locks in the public command surface so a
+// future refactor doesn't silently drop run/status/etc. The `update` verb
+// was intentionally removed when lark-sec-cli took over its own upgrade
+// lifecycle; if it ever needs to come back, add it here too. `install` was
+// removed because `sec run --auto-install` (default on) makes a standalone
+// install verb redundant.
+func TestNewCmdSec_HasAllSubcommands(t *testing.T) {
+	f, _, _, _ := cmdutil.TestFactory(t, &core.CliConfig{AppID: "a", AppSecret: "s"})
+	cmd := NewCmdSec(f)
+
+	var got []string
+	for _, c := range cmd.Commands() {
+		got = append(got, c.Name())
+	}
+	sort.Strings(got)
+	want := []string{"config", "run", "status", "stop"}
+	if len(got) != len(want) {
+		t.Fatalf("subcommands = %v, want %v", got, want)
+	}
+	for i, name := range want {
+		if got[i] != name {
+			t.Errorf("subcommands[%d] = %q, want %q", i, got[i], name)
+		}
+	}
+}

cmd/sec/status.go

@@ -0,0 +1,115 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+
+	"github.com/spf13/cobra"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/output"
+	intsec "github.com/larksuite/cli/internal/sec"
+)
+
+// StatusOptions holds inputs for `lark-cli sec status`.
+type StatusOptions struct {
+	Factory *cmdutil.Factory
+}
+
+// NewCmdSecStatus shows install + runtime state. Implementation strategy:
+//
+//  1. Read lark-cli's local install record (state.json) — works even when the
+//     daemon's not installed, and gives the user a version/buildId/path
+//     fingerprint regardless of whether the service is up.
+//  2. If the install exists, shell out to `lark-sec-cli status` for the
+//     live daemon view (service registration, pid liveness, proxy probe,
+//     sec_config.json contents). The daemon's own status command does a
+//     thorough check; we just pass it through.
+func NewCmdSecStatus(f *cmdutil.Factory, runF func(*StatusOptions) error) *cobra.Command {
+	opts := &StatusOptions{Factory: f}
+	cmd := &cobra.Command{
+		Use:   "status",
+		Short: "Show lark-sec-cli install and runtime state",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if runF != nil {
+				return runF(opts)
+			}
+			return runStatus(cmd, opts)
+		},
+	}
+	return cmd
+}
+
+func runStatus(cmd *cobra.Command, opts *StatusOptions) error {
+	errOut := opts.Factory.IOStreams.ErrOut
+	trace := verboseOut(cmd, errOut)
+
+	tracef(trace, "sec status", "constructing installer (lazy credentials)")
+	_, paths, err := installer(opts.Factory)
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "internal", "%v", err)
+	}
+	out := opts.Factory.IOStreams.Out
+	tracef(trace, "sec status", "loading state from %s", paths.StateFile())
+	state, err := intsec.LoadState(paths.StateFile())
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "internal", "load sec state: %v", err)
+	}
+	if state == nil {
+		fmt.Fprintln(out, "lark-sec-cli: not installed")
+		fmt.Fprintln(out, "  run: lark-cli sec run")
+		return nil
+	}
+	fmt.Fprintf(out, "lark-sec-cli %s\n", state.Version)
+	fmt.Fprintf(out, "  binary: %s\n", state.BinaryPath)
+
+	// Daemon-side detail via `lark-sec-cli status`. The daemon's status
+	// command already covers service registration + pid + proxy reachability
+	// + bridge file — better than re-implementing those here.
+	tracef(trace, "sec status", "shelling out to %s status", state.BinaryPath)
+	c := exec.CommandContext(cmd.Context(), state.BinaryPath, "status")
+	var stdout, stderr bytes.Buffer
+	c.Stdout = &stdout
+	c.Stderr = &stderr
+	runErr := c.Run()
+	tracef(trace, "sec status", "daemon status exit=%v stdout=%d bytes stderr=%d bytes", runErr, stdout.Len(), stderr.Len())
+	fmt.Fprintln(out, "  --- lark-sec-cli status ---")
+	if stdout.Len() > 0 {
+		fmt.Fprint(out, indent(stdout.String(), "  "))
+	}
+	if stderr.Len() > 0 {
+		fmt.Fprint(out, indent(stderr.String(), "  "))
+	}
+	// `lark-sec-cli status` exits 1 when not running — that's diagnostic
+	// data, not a failure of OUR command. Surface it for the user but don't
+	// propagate the non-zero exit upward.
+	_ = runErr
+	return nil
+}
+
+// indent prefixes every line of s with prefix. Cheap pass-through formatter
+// used to make the embedded `lark-sec-cli status` output read as a sub-block
+// under our own header.
+func indent(s, prefix string) string {
+	if s == "" {
+		return s
+	}
+	var buf bytes.Buffer
+	start := 0
+	for i := 0; i < len(s); i++ {
+		if s[i] == '\n' {
+			buf.WriteString(prefix)
+			buf.WriteString(s[start : i+1])
+			start = i + 1
+		}
+	}
+	if start < len(s) {
+		buf.WriteString(prefix)
+		buf.WriteString(s[start:])
+	}
+	return buf.String()
+}

cmd/sec/stop.go

@@ -0,0 +1,82 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+
+	"github.com/spf13/cobra"
+
+	"github.com/larksuite/cli/internal/cmdutil"
+	"github.com/larksuite/cli/internal/output"
+	intsec "github.com/larksuite/cli/internal/sec"
+)
+
+// StopOptions holds inputs for `lark-cli sec stop`.
+type StopOptions struct {
+	Factory *cmdutil.Factory
+}
+
+// NewCmdSecStop disables and removes the lark-sec-cli user system service.
+// Counterpart to `sec run` — internally invokes `lark-sec-cli service disable`,
+// which uninstalls the launchd / systemd / VBS-watchdog registration.
+//
+// The daemon itself wipes ~/.lark-cli/sec_config.json on shutdown (see its
+// --disable-on-exit flag, default true), so subsequent lark-cli runs route
+// directly to the upstream API instead of dangling through a dead local proxy.
+func NewCmdSecStop(f *cmdutil.Factory, runF func(*StopOptions) error) *cobra.Command {
+	opts := &StopOptions{Factory: f}
+	cmd := &cobra.Command{
+		Use:   "stop",
+		Short: "Disable and remove the lark-sec-cli user system service",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if runF != nil {
+				return runF(opts)
+			}
+			return runStop(cmd, opts)
+		},
+	}
+	return cmd
+}
+
+func runStop(cmd *cobra.Command, opts *StopOptions) error {
+	out := opts.Factory.IOStreams.ErrOut
+	trace := verboseOut(cmd, out)
+
+	tracef(trace, "sec stop", "constructing installer (lazy credentials)")
+	_, paths, err := installer(opts.Factory)
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "internal", "%v", err)
+	}
+	tracef(trace, "sec stop", "loading state from %s", paths.StateFile())
+	state, err := intsec.LoadState(paths.StateFile())
+	if err != nil {
+		return output.Errorf(output.ExitInternal, "internal", "load sec state: %v", err)
+	}
+	if state == nil {
+		// Nothing on disk to stop — no-op.
+		tracef(trace, "sec stop", "no install on disk; nothing to stop")
+		output.PrintSuccess(out, "lark-sec-cli not installed; nothing to stop")
+		return nil
+	}
+
+	args := []string{"service", "disable"}
+	fmt.Fprintf(out, "Running: %s %v\n", state.BinaryPath, args)
+	tracef(trace, "sec stop", "shelling out to %s %v", state.BinaryPath, args)
+
+	c := exec.CommandContext(cmd.Context(), state.BinaryPath, args...)
+	var stdout, stderr bytes.Buffer
+	c.Stdout = &stdout
+	c.Stderr = &stderr
+	if err := c.Run(); err != nil {
+		return output.Errorf(output.ExitInternal, "sec_service_disable",
+			"`lark-sec-cli service disable` failed: %v\nstderr: %s", err, stderr.String())
+	}
+	tracef(trace, "sec stop", "service disable returned ok (%d bytes stdout)", stdout.Len())
+	fmt.Fprint(out, stdout.String())
+	output.PrintSuccess(out, "lark-sec-cli service disabled")
+	return nil
+}

cmd/sec/verbose.go

@@ -0,0 +1,32 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/spf13/cobra"
+)
+
+// verboseOut returns the trace destination for a sec subcommand: the given
+// stderr writer when the inherited --verbose / -v flag is set, otherwise nil.
+// Pair with tracef — a nil destination silently drops traces, so callers can
+// emit unconditionally.
+func verboseOut(cmd *cobra.Command, errOut io.Writer) io.Writer {
+	if v, _ := cmd.Flags().GetBool("verbose"); v {
+		return errOut
+	}
+	return nil
+}
+
+// tracef writes one trace line to w when w is non-nil. The prefix names the
+// emitting subcommand (e.g. "sec run") so layered output from the install
+// pipeline + the command itself stays distinguishable.
+func tracef(w io.Writer, prefix, format string, args ...any) {
+	if w == nil {
+		return
+	}
+	fmt.Fprintf(w, "[%s] "+format+"\n", append([]any{prefix}, args...)...)
+}

extension/credential/secplugin/provider.go

@@ -0,0 +1,227 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+// Package secplugin provides a placeholder credential provider for SEC_AUTH mode.
+//
+// When ~/.lark-cli/sec_config.json has:
+//
+//	LARKSUITE_CLI_SEC_ENABLE=true
+//	LARKSUITE_CLI_SEC_AUTH=true
+//
+// this provider returns a minimal Account and placeholder tokens. The proxy
+// is expected to replace the placeholder tokens with real ones.
+package secplugin
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/larksuite/cli/extension/credential"
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/envvars"
+	internalsec "github.com/larksuite/cli/internal/secplugin"
+)
+
+// Provider supplies placeholder credentials when SEC_AUTH mode is enabled.
+type Provider struct{}
+
+// Name returns the registered credential provider name.
+func (p *Provider) Name() string { return "secplugin" }
+
+// Priority is higher than env (default 10) but lower than sidecar (0),
+// so authsidecar builds keep sidecar semantics when both are present.
+func (p *Provider) Priority() int { return 1 }
+
+// loadSecConfig is replaceable in tests so provider behavior can be isolated
+// from on-disk SEC configuration state.
+var loadSecConfig = internalsec.Load
+
+func validateDefaultAs(value string) error {
+	switch id := credential.Identity(strings.TrimSpace(value)); id {
+	case "", credential.IdentityAuto, credential.IdentityUser, credential.IdentityBot:
+		return nil
+	default:
+		return fmt.Errorf("invalid %s %q (want user, bot, or auto)", envvars.CliDefaultAs, id)
+	}
+}
+
+// ResolveAccount builds an account that advertises SEC_AUTH placeholder support.
+func (p *Provider) ResolveAccount(ctx context.Context) (*credential.Account, error) {
+	cfg, err := loadSecConfig()
+	if err != nil {
+		return nil, &credential.BlockError{Provider: p.Name(), Reason: err.Error()}
+	}
+	if cfg == nil || !cfg.AuthEnabled() {
+		return nil, nil
+	}
+
+	appID := strings.TrimSpace(os.Getenv(envvars.CliAppID))
+	brand := credential.Brand(strings.TrimSpace(os.Getenv(envvars.CliBrand)))
+	var defaultAs credential.Identity
+
+	// Prefer explicit env; if missing, allow sec_config.json to provide defaults.
+	if appID == "" && strings.TrimSpace(cfg.AppID) != "" {
+		appID = strings.TrimSpace(cfg.AppID)
+	}
+	if brand == "" && strings.TrimSpace(cfg.Brand) != "" {
+		brand = credential.Brand(strings.TrimSpace(cfg.Brand))
+	}
+	if defaultAs == "" && strings.TrimSpace(cfg.DefaultAs) != "" {
+		defaultAs = credential.Identity(strings.TrimSpace(cfg.DefaultAs))
+		if err := validateDefaultAs(string(defaultAs)); err != nil {
+			return nil, &credential.BlockError{
+				Provider: p.Name(),
+				Reason:   err.Error(),
+			}
+		}
+	}
+
+	// Prefer explicit env for sandbox use; otherwise fall back to on-disk config
+	// without resolving any secrets.
+	if appID == "" || brand == "" {
+		multi, err := core.LoadMultiAppConfig()
+		if err != nil || multi == nil {
+			return nil, &credential.BlockError{
+				Provider: p.Name(),
+				Reason:   "SEC_AUTH is enabled but no app config is available; run `lark-cli config init --new` (trusted env), or set " + envvars.CliAppID + " and " + envvars.CliBrand,
+			}
+		}
+		app := multi.CurrentAppConfig("") // profile override not available in provider API
+		if app == nil {
+			return nil, &credential.BlockError{
+				Provider: p.Name(),
+				Reason:   "SEC_AUTH is enabled but no active profile is available in config.json",
+			}
+		}
+		if appID == "" {
+			appID = app.AppId
+		}
+		if brand == "" {
+			brand = credential.Brand(app.Brand)
+		}
+		if defaultAs == "" {
+			defaultAs = credential.Identity(app.DefaultAs)
+		}
+
+		// Map strict mode to supported identities (0 = allow all).
+		mode := multi.StrictMode
+		if app.StrictMode != nil {
+			mode = *app.StrictMode
+		}
+		switch mode {
+		case core.StrictModeBot:
+			// Keep sandbox locked down to bot.
+			return &credential.Account{
+				AppID:               appID,
+				AppSecret:           credential.NoAppSecret,
+				Brand:               brand,
+				DefaultAs:           defaultAs,
+				SupportedIdentities: credential.SupportsBot,
+			}, nil
+		case core.StrictModeUser:
+			return &credential.Account{
+				AppID:               appID,
+				AppSecret:           credential.NoAppSecret,
+				Brand:               brand,
+				DefaultAs:           defaultAs,
+				SupportedIdentities: credential.SupportsUser,
+			}, nil
+		}
+	}
+
+	if appID == "" {
+		return nil, &credential.BlockError{
+			Provider: p.Name(),
+			Reason:   "SEC_AUTH is enabled but " + envvars.CliAppID + " is missing",
+		}
+	}
+	if brand == "" {
+		brand = credential.BrandFeishu
+	}
+	if brand != credential.BrandFeishu && brand != credential.BrandLark {
+		return nil, &credential.BlockError{
+			Provider: p.Name(),
+			Reason:   fmt.Sprintf("invalid %s %q (want feishu or lark)", envvars.CliBrand, brand),
+		}
+	}
+
+	// DefaultAs comes from env if present (optional).
+	envDefaultAs := strings.TrimSpace(os.Getenv(envvars.CliDefaultAs))
+	if err := validateDefaultAs(envDefaultAs); err != nil {
+		return nil, &credential.BlockError{
+			Provider: p.Name(),
+			Reason:   err.Error(),
+		}
+	}
+	switch id := credential.Identity(envDefaultAs); id {
+	case "", credential.IdentityAuto:
+		// keep defaultAs from config/env; empty is allowed
+	case credential.IdentityUser, credential.IdentityBot:
+		defaultAs = id
+	}
+
+	// If STRICT_MODE env is not set, allow sec_config.json to provide a default.
+	strictModeRaw := strings.TrimSpace(os.Getenv(envvars.CliStrictMode))
+	if strictModeRaw == "" && strings.TrimSpace(cfg.StrictMode) != "" {
+		strictModeRaw = strings.TrimSpace(cfg.StrictMode)
+	}
+
+	// SupportedIdentities from STRICT_MODE (optional). Default: allow both.
+	support := credential.SupportsAll
+	switch strictMode := strictModeRaw; strictMode {
+	case "bot":
+		support = credential.SupportsBot
+	case "user":
+		support = credential.SupportsUser
+	case "off", "":
+		// Keep the default: allow both identities.
+	default:
+		return nil, &credential.BlockError{
+			Provider: p.Name(),
+			Reason:   fmt.Sprintf("invalid %s %q (want bot, user, or off)", envvars.CliStrictMode, strictMode),
+		}
+	}
+
+	return &credential.Account{
+		AppID:               appID,
+		AppSecret:           credential.NoAppSecret,
+		Brand:               brand,
+		DefaultAs:           defaultAs,
+		SupportedIdentities: support,
+	}, nil
+}
+
+// ResolveToken returns placeholder tokens that a trusted proxy must replace.
+func (p *Provider) ResolveToken(ctx context.Context, req credential.TokenSpec) (*credential.Token, error) {
+	cfg, err := internalsec.Load()
+	if err != nil {
+		return nil, &credential.BlockError{Provider: p.Name(), Reason: err.Error()}
+	}
+	if cfg == nil || !cfg.AuthEnabled() {
+		return nil, nil
+	}
+
+	switch req.Type {
+	case credential.TokenTypeUAT:
+		return &credential.Token{
+			Value:  internalsec.SentinelUAT,
+			Scopes: "", // empty => skip scope pre-check
+			Source: "secplugin",
+		}, nil
+	case credential.TokenTypeTAT:
+		return &credential.Token{
+			Value:  internalsec.SentinelTAT,
+			Scopes: "",
+			Source: "secplugin",
+		}, nil
+	default:
+		return nil, nil
+	}
+}
+
+// init registers the SEC_AUTH placeholder credential provider.
+func init() {
+	credential.Register(&Provider{})
+}

extension/credential/secplugin/provider_test.go

@@ -0,0 +1,486 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package secplugin
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/larksuite/cli/extension/credential"
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/envvars"
+	internalsec "github.com/larksuite/cli/internal/secplugin"
+)
+
+// TestProvider_Metadata verifies the registered provider metadata.
+func TestProvider_Metadata(t *testing.T) {
+	p := &Provider{}
+	if p.Name() != "secplugin" {
+		t.Fatalf("Name() = %q, want secplugin", p.Name())
+	}
+	if p.Priority() != 1 {
+		t.Fatalf("Priority() = %d, want 1", p.Priority())
+	}
+}
+
+// TestProvider_UsesSecConfigDefaults verifies that SEC config defaults populate
+// the placeholder account when env vars are absent.
+func TestProvider_UsesSecConfigDefaults(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	loadSecConfig = func() (*internalsec.Config, error) {
+		return &internalsec.Config{
+			Enable:     true,
+			Auth:       true,
+			AppID:      "cli_test_app",
+			Brand:      "lark",
+			DefaultAs:  "bot",
+			StrictMode: "bot",
+		}, nil
+	}
+
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliBrand, "")
+	t.Setenv(envvars.CliDefaultAs, "")
+	t.Setenv(envvars.CliStrictMode, "")
+
+	p := &Provider{}
+	acct, err := p.ResolveAccount(context.Background())
+	if err != nil {
+		t.Fatalf("ResolveAccount() error = %v", err)
+	}
+	if acct == nil {
+		t.Fatal("ResolveAccount() = nil, want account")
+	}
+	if acct.AppID != "cli_test_app" {
+		t.Fatalf("acct.AppID = %q, want %q", acct.AppID, "cli_test_app")
+	}
+	if string(acct.Brand) != "lark" {
+		t.Fatalf("acct.Brand = %q, want %q", acct.Brand, "lark")
+	}
+	if string(acct.DefaultAs) != "bot" {
+		t.Fatalf("acct.DefaultAs = %q, want %q", acct.DefaultAs, "bot")
+	}
+	// StrictMode=bot => SupportsBot only.
+	if acct.SupportedIdentities != 2 {
+		t.Fatalf("acct.SupportedIdentities = %d, want %d (SupportsBot)", acct.SupportedIdentities, 2)
+	}
+}
+
+// TestProvider_EnvOverridesSecConfigDefaults verifies that explicit environment
+// variables override SEC config defaults.
+func TestProvider_EnvOverridesSecConfigDefaults(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	loadSecConfig = func() (*internalsec.Config, error) {
+		return &internalsec.Config{
+			Enable:     true,
+			Auth:       true,
+			AppID:      "cli_test_app",
+			Brand:      "feishu",
+			DefaultAs:  "bot",
+			StrictMode: "bot",
+		}, nil
+	}
+
+	t.Setenv(envvars.CliAppID, "cli_env_app")
+	t.Setenv(envvars.CliBrand, "lark")
+	t.Setenv(envvars.CliDefaultAs, "user")
+	t.Setenv(envvars.CliStrictMode, "user")
+
+	p := &Provider{}
+	acct, err := p.ResolveAccount(context.Background())
+	if err != nil {
+		t.Fatalf("ResolveAccount() error = %v", err)
+	}
+	if acct == nil {
+		t.Fatal("ResolveAccount() = nil, want account")
+	}
+	if acct.AppID != "cli_env_app" {
+		t.Fatalf("acct.AppID = %q, want %q", acct.AppID, "cli_env_app")
+	}
+	if string(acct.Brand) != "lark" {
+		t.Fatalf("acct.Brand = %q, want %q", acct.Brand, "lark")
+	}
+	if string(acct.DefaultAs) != "user" {
+		t.Fatalf("acct.DefaultAs = %q, want %q", acct.DefaultAs, "user")
+	}
+	// StrictMode=user => SupportsUser only (bit 1).
+	if acct.SupportedIdentities != 1 {
+		t.Fatalf("acct.SupportedIdentities = %d, want %d (SupportsUser)", acct.SupportedIdentities, 1)
+	}
+}
+
+// TestProvider_ResolveAccount_ReturnsNilWhenDisabled verifies early nil returns
+// when SEC_AUTH mode is unavailable.
+func TestProvider_ResolveAccount_ReturnsNilWhenDisabled(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	cases := []struct {
+		name string
+		cfg  *internalsec.Config
+	}{
+		{name: "nil config", cfg: nil},
+		{name: "auth disabled", cfg: &internalsec.Config{Enable: true, Auth: false}},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			loadSecConfig = func() (*internalsec.Config, error) { return tt.cfg, nil }
+			acct, err := (&Provider{}).ResolveAccount(context.Background())
+			if err != nil {
+				t.Fatalf("ResolveAccount() error = %v", err)
+			}
+			if acct != nil {
+				t.Fatalf("ResolveAccount() = %#v, want nil", acct)
+			}
+		})
+	}
+}
+
+// TestProvider_ResolveAccount_LoadErrorBlocks verifies that SEC config load failures
+// stop provider resolution.
+func TestProvider_ResolveAccount_LoadErrorBlocks(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	loadSecConfig = func() (*internalsec.Config, error) {
+		return nil, context.DeadlineExceeded
+	}
+
+	acct, err := (&Provider{}).ResolveAccount(context.Background())
+	if err == nil {
+		t.Fatal("ResolveAccount() error = nil, want block error")
+	}
+	if acct != nil {
+		t.Fatalf("ResolveAccount() = %#v, want nil", acct)
+	}
+	blockErr, ok := err.(*credential.BlockError)
+	if !ok {
+		t.Fatalf("ResolveAccount() error = %T, want *credential.BlockError", err)
+	}
+	if blockErr.Provider != "secplugin" {
+		t.Fatalf("blockErr.Provider = %q, want secplugin", blockErr.Provider)
+	}
+	if !strings.Contains(blockErr.Reason, context.DeadlineExceeded.Error()) {
+		t.Fatalf("blockErr.Reason = %q, want load error text", blockErr.Reason)
+	}
+}
+
+// TestProvider_ResolveAccount_DefaultsBrandAndSupport verifies fallback defaults
+// for brand and supported identities.
+func TestProvider_ResolveAccount_DefaultsBrandAndSupport(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	loadSecConfig = func() (*internalsec.Config, error) {
+		return &internalsec.Config{
+			Enable: true,
+			Auth:   true,
+		}, nil
+	}
+
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliBrand, "")
+	t.Setenv(envvars.CliDefaultAs, "")
+	t.Setenv(envvars.CliStrictMode, "")
+	if err := core.SaveMultiAppConfig(&core.MultiAppConfig{
+		Apps: []core.AppConfig{{
+			Name:      "default",
+			AppId:     "app_from_disk",
+			AppSecret: core.PlainSecret("secret"),
+			DefaultAs: core.AsBot,
+		}},
+	}); err != nil {
+		t.Fatalf("SaveMultiAppConfig() error = %v", err)
+	}
+
+	acct, err := (&Provider{}).ResolveAccount(context.Background())
+	if err != nil {
+		t.Fatalf("ResolveAccount() error = %v", err)
+	}
+	if acct == nil {
+		t.Fatal("ResolveAccount() = nil, want account")
+	}
+	if acct.Brand != credential.BrandFeishu {
+		t.Fatalf("acct.Brand = %q, want %q", acct.Brand, credential.BrandFeishu)
+	}
+	if acct.SupportedIdentities != credential.SupportsAll {
+		t.Fatalf("acct.SupportedIdentities = %d, want %d", acct.SupportedIdentities, credential.SupportsAll)
+	}
+	if acct.DefaultAs != credential.Identity("bot") {
+		t.Fatalf("acct.DefaultAs = %q, want bot", acct.DefaultAs)
+	}
+	if acct.AppID != "app_from_disk" {
+		t.Fatalf("acct.AppID = %q, want app_from_disk", acct.AppID)
+	}
+}
+
+// TestProvider_ResolveAccount_InvalidValuesBlock verifies validation failures for
+// brand and identity-related settings.
+func TestProvider_ResolveAccount_InvalidValuesBlock(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	cases := []struct {
+		name     string
+		cfg      *internalsec.Config
+		envKey   string
+		envValue string
+		want     string
+	}{
+		{
+			name: "invalid brand from config",
+			cfg:  &internalsec.Config{Enable: true, Auth: true, AppID: "cli_test_app", Brand: "bad-brand"},
+			want: "invalid " + envvars.CliBrand,
+		},
+		{
+			name: "invalid default as from config",
+			cfg: &internalsec.Config{
+				Enable:    true,
+				Auth:      true,
+				AppID:     "cli_test_app",
+				Brand:     "lark",
+				DefaultAs: "bad",
+			},
+			want: "invalid " + envvars.CliDefaultAs,
+		},
+		{
+			name:     "invalid default as from env",
+			cfg:      &internalsec.Config{Enable: true, Auth: true, AppID: "cli_test_app", Brand: "lark"},
+			envKey:   envvars.CliDefaultAs,
+			envValue: "bad",
+			want:     "invalid " + envvars.CliDefaultAs,
+		},
+		{
+			name:     "invalid strict mode from env",
+			cfg:      &internalsec.Config{Enable: true, Auth: true, AppID: "cli_test_app", Brand: "lark"},
+			envKey:   envvars.CliStrictMode,
+			envValue: "bad",
+			want:     "invalid " + envvars.CliStrictMode,
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			loadSecConfig = func() (*internalsec.Config, error) { return tt.cfg, nil }
+			t.Setenv(envvars.CliAppID, "")
+			t.Setenv(envvars.CliBrand, "")
+			t.Setenv(envvars.CliDefaultAs, "")
+			t.Setenv(envvars.CliStrictMode, "")
+			if tt.envKey != "" {
+				t.Setenv(tt.envKey, tt.envValue)
+			}
+
+			acct, err := (&Provider{}).ResolveAccount(context.Background())
+			if err == nil {
+				t.Fatal("ResolveAccount() error = nil, want block error")
+			}
+			if acct != nil {
+				t.Fatalf("ResolveAccount() = %#v, want nil", acct)
+			}
+			blockErr, ok := err.(*credential.BlockError)
+			if !ok {
+				t.Fatalf("ResolveAccount() error = %T, want *credential.BlockError", err)
+			}
+			if !strings.Contains(blockErr.Reason, tt.want) {
+				t.Fatalf("blockErr.Reason = %q, want substring %q", blockErr.Reason, tt.want)
+			}
+		})
+	}
+}
+
+// TestProvider_ResolveAccount_FallbackToDiskConfig verifies fallback behavior
+// when SEC config omits app identity fields.
+func TestProvider_ResolveAccount_FallbackToDiskConfig(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	loadSecConfig = func() (*internalsec.Config, error) {
+		return &internalsec.Config{Enable: true, Auth: true}, nil
+	}
+
+	t.Run("missing config blocks", func(t *testing.T) {
+		t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+		t.Setenv(envvars.CliAppID, "")
+		t.Setenv(envvars.CliBrand, "")
+		acct, err := (&Provider{}).ResolveAccount(context.Background())
+		if err == nil {
+			t.Fatal("ResolveAccount() error = nil, want block error")
+		}
+		if acct != nil {
+			t.Fatalf("ResolveAccount() = %#v, want nil", acct)
+		}
+		blockErr := err.(*credential.BlockError)
+		if !strings.Contains(blockErr.Reason, "no app config is available") {
+			t.Fatalf("blockErr.Reason = %q, want missing app config message", blockErr.Reason)
+		}
+	})
+
+	t.Run("missing active profile blocks", func(t *testing.T) {
+		t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+		if err := core.SaveMultiAppConfig(&core.MultiAppConfig{
+			CurrentApp: "missing",
+			Apps: []core.AppConfig{{
+				Name:      "default",
+				AppId:     "app_from_disk",
+				AppSecret: core.PlainSecret("secret"),
+				Brand:     core.LarkBrand("lark"),
+			}},
+		}); err != nil {
+			t.Fatalf("SaveMultiAppConfig() error = %v", err)
+		}
+
+		acct, err := (&Provider{}).ResolveAccount(context.Background())
+		if err == nil {
+			t.Fatal("ResolveAccount() error = nil, want block error")
+		}
+		if acct != nil {
+			t.Fatalf("ResolveAccount() = %#v, want nil", acct)
+		}
+		blockErr := err.(*credential.BlockError)
+		if !strings.Contains(blockErr.Reason, "no active profile") {
+			t.Fatalf("blockErr.Reason = %q, want no active profile message", blockErr.Reason)
+		}
+	})
+
+	t.Run("strict mode from disk", func(t *testing.T) {
+		cases := []struct {
+			name    string
+			mode    core.StrictMode
+			wantIDs credential.IdentitySupport
+		}{
+			{name: "bot", mode: core.StrictModeBot, wantIDs: credential.SupportsBot},
+			{name: "user", mode: core.StrictModeUser, wantIDs: credential.SupportsUser},
+		}
+
+		for _, tt := range cases {
+			t.Run(tt.name, func(t *testing.T) {
+				t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+				mode := tt.mode
+				if err := core.SaveMultiAppConfig(&core.MultiAppConfig{
+					Apps: []core.AppConfig{{
+						Name:       "default",
+						AppId:      "app_from_disk",
+						AppSecret:  core.PlainSecret("secret"),
+						Brand:      core.LarkBrand("lark"),
+						DefaultAs:  core.AsBot,
+						StrictMode: &mode,
+					}},
+				}); err != nil {
+					t.Fatalf("SaveMultiAppConfig() error = %v", err)
+				}
+
+				acct, err := (&Provider{}).ResolveAccount(context.Background())
+				if err != nil {
+					t.Fatalf("ResolveAccount() error = %v", err)
+				}
+				if acct == nil {
+					t.Fatal("ResolveAccount() = nil, want account")
+				}
+				if acct.AppID != "app_from_disk" {
+					t.Fatalf("acct.AppID = %q, want app_from_disk", acct.AppID)
+				}
+				if acct.Brand != credential.Brand("lark") {
+					t.Fatalf("acct.Brand = %q, want lark", acct.Brand)
+				}
+				if acct.DefaultAs != credential.Identity("bot") {
+					t.Fatalf("acct.DefaultAs = %q, want bot", acct.DefaultAs)
+				}
+				if acct.SupportedIdentities != tt.wantIDs {
+					t.Fatalf("acct.SupportedIdentities = %d, want %d", acct.SupportedIdentities, tt.wantIDs)
+				}
+			})
+		}
+	})
+}
+
+// TestProvider_ResolveAccount_StrictModePreservesConfiguredDefaultAs verifies
+// cfg.DefaultAs is not overwritten by disk profile default in strict-mode path.
+func TestProvider_ResolveAccount_StrictModePreservesConfiguredDefaultAs(t *testing.T) {
+	prev := loadSecConfig
+	t.Cleanup(func() { loadSecConfig = prev })
+
+	loadSecConfig = func() (*internalsec.Config, error) {
+		return &internalsec.Config{
+			Enable:     true,
+			Auth:       true,
+			Brand:      "lark",
+			DefaultAs:  "user",
+			StrictMode: "bot",
+		}, nil
+	}
+
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	t.Setenv(envvars.CliAppID, "")
+	t.Setenv(envvars.CliBrand, "")
+	t.Setenv(envvars.CliDefaultAs, "")
+	t.Setenv(envvars.CliStrictMode, "")
+	if err := core.SaveMultiAppConfig(&core.MultiAppConfig{
+		Apps: []core.AppConfig{{
+			Name:      "default",
+			AppId:     "app_from_disk",
+			AppSecret: core.PlainSecret("secret"),
+			Brand:     core.LarkBrand("lark"),
+			DefaultAs: core.AsBot,
+		}},
+	}); err != nil {
+		t.Fatalf("SaveMultiAppConfig() error = %v", err)
+	}
+
+	acct, err := (&Provider{}).ResolveAccount(context.Background())
+	if err != nil {
+		t.Fatalf("ResolveAccount() error = %v", err)
+	}
+	if acct == nil {
+		t.Fatal("ResolveAccount() = nil, want account")
+	}
+	if acct.DefaultAs != credential.IdentityUser {
+		t.Fatalf("acct.DefaultAs = %q, want %q", acct.DefaultAs, credential.IdentityUser)
+	}
+	if acct.SupportedIdentities != credential.SupportsBot {
+		t.Fatalf("acct.SupportedIdentities = %d, want %d (SupportsBot)", acct.SupportedIdentities, credential.SupportsBot)
+	}
+}
+
+// TestProvider_ResolveToken_ReturnsSentinels verifies placeholder token behavior
+// for SEC_AUTH mode.
+func TestProvider_ResolveToken_ReturnsSentinels(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	t.Setenv(envvars.CliSecEnable, "true")
+	t.Setenv(envvars.CliSecAuth, "true")
+	t.Setenv(envvars.CliSecProxy, "http://127.0.0.1:3128")
+	t.Setenv(envvars.CliSecCA, "")
+
+	p := &Provider{}
+
+	uat, err := p.ResolveToken(context.Background(), credential.TokenSpec{Type: credential.TokenTypeUAT})
+	if err != nil {
+		t.Fatalf("ResolveToken(UAT) error = %v", err)
+	}
+	if uat == nil || uat.Value != internalsec.SentinelUAT || uat.Source != "secplugin" {
+		t.Fatalf("ResolveToken(UAT) = %#v, want sentinel UAT token", uat)
+	}
+
+	tat, err := p.ResolveToken(context.Background(), credential.TokenSpec{Type: credential.TokenTypeTAT})
+	if err != nil {
+		t.Fatalf("ResolveToken(TAT) error = %v", err)
+	}
+	if tat == nil || tat.Value != internalsec.SentinelTAT || tat.Source != "secplugin" {
+		t.Fatalf("ResolveToken(TAT) = %#v, want sentinel TAT token", tat)
+	}
+
+	tok, err := p.ResolveToken(context.Background(), credential.TokenSpec{Type: credential.TokenType("other")})
+	if err != nil {
+		t.Fatalf("ResolveToken(other) error = %v", err)
+	}
+	if tok != nil {
+		t.Fatalf("ResolveToken(other) = %#v, want nil", tok)
+	}
+}

internal/envvars/envvars.go

@@ -4,18 +4,45 @@
 package envvars
 
 const (
-	CliAppID             = "LARKSUITE_CLI_APP_ID"
-	CliAppSecret         = "LARKSUITE_CLI_APP_SECRET"
-	CliBrand             = "LARKSUITE_CLI_BRAND"
-	CliUserAccessToken   = "LARKSUITE_CLI_USER_ACCESS_TOKEN"
+	// CliAppID is the app ID environment variable consumed by the CLI.
+	CliAppID = "LARKSUITE_CLI_APP_ID"
+
+	// CliAppSecret is the app secret environment variable consumed by the CLI.
+	CliAppSecret = "LARKSUITE_CLI_APP_SECRET"
+
+	// CliBrand selects the tenant brand environment variable consumed by the CLI.
+	CliBrand = "LARKSUITE_CLI_BRAND"
+
+	// CliUserAccessToken is the user access token override environment variable.
+	CliUserAccessToken = "LARKSUITE_CLI_USER_ACCESS_TOKEN"
+
+	// CliTenantAccessToken is the tenant access token override environment variable.
 	CliTenantAccessToken = "LARKSUITE_CLI_TENANT_ACCESS_TOKEN"
-	CliDefaultAs         = "LARKSUITE_CLI_DEFAULT_AS"
-	CliStrictMode        = "LARKSUITE_CLI_STRICT_MODE"
 
-	// Sidecar proxy (auth proxy mode)
+	// CliDefaultAs selects the default identity environment variable.
+	CliDefaultAs = "LARKSUITE_CLI_DEFAULT_AS"
+
+	// CliStrictMode selects the strict identity mode environment variable.
+	CliStrictMode = "LARKSUITE_CLI_STRICT_MODE"
+
+	// CliAuthProxy is the auth sidecar HTTP address environment variable.
 	CliAuthProxy = "LARKSUITE_CLI_AUTH_PROXY" // sidecar HTTP address, e.g. "http://127.0.0.1:16384"
-	CliProxyKey  = "LARKSUITE_CLI_PROXY_KEY"  // HMAC signing key shared with sidecar
 
-	// Content safety scanning mode
+	// CliProxyKey is the shared HMAC signing key environment variable for the sidecar.
+	CliProxyKey = "LARKSUITE_CLI_PROXY_KEY" // HMAC signing key shared with sidecar
+
+	// CliSecEnable enables sec plugin mode from the environment.
+	CliSecEnable = "LARKSUITE_CLI_SEC_ENABLE"
+
+	// CliSecProxy sets the fixed sec plugin HTTP proxy address.
+	CliSecProxy = "LARKSUITE_CLI_SEC_PROXY"
+
+	// CliSecCA points to an extra PEM bundle trusted by sec plugin mode.
+	CliSecCA = "LARKSUITE_CLI_SEC_CA"
+
+	// CliSecAuth enables placeholder-token auth mode for sec plugin flows.
+	CliSecAuth = "LARKSUITE_CLI_SEC_AUTH"
+
+	// CliContentSafetyMode selects the content safety scanning mode.
 	CliContentSafetyMode = "LARKSUITE_CLI_CONTENT_SAFETY_MODE"
 )

internal/sec/archive.go

@@ -0,0 +1,138 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"archive/zip"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// maxArchiveBytes is a sanity ceiling for total uncompressed size to prevent
+// a malicious or corrupt zip from filling the disk. The lark-sec-cli zip is a
+// single binary plus one shared library; 1 GiB is several orders of magnitude
+// over the real size and well under most users' free disk.
+const maxArchiveBytes = 1 << 30
+
+// ExtractZip unpacks src into dst, refusing entries whose target paths would
+// escape dst (zip slip). Existing files inside dst are overwritten; dst must
+// already exist.
+//
+// Executable permission is preserved when the zip stores POSIX mode bits;
+// otherwise we apply 0o755 to suspected binaries (matching BinaryName() /
+// legacy names or anything *.dylib/*.so/*.dll) and 0o644 to everything else.
+func ExtractZip(src, dst string) error {
+	r, err := zip.OpenReader(src)
+	if err != nil {
+		return fmt.Errorf("open zip: %w", err)
+	}
+	defer r.Close()
+
+	dstAbs, err := filepath.Abs(dst)
+	if err != nil {
+		return err
+	}
+
+	var totalSize uint64
+	for _, f := range r.File {
+		totalSize += f.UncompressedSize64
+		if totalSize > maxArchiveBytes {
+			return fmt.Errorf("zip exceeds %d bytes; refusing", maxArchiveBytes)
+		}
+		if err := extractZipEntry(f, dstAbs); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func extractZipEntry(f *zip.File, dstAbs string) error {
+	// Reject absolute paths and any traversal segments. filepath.Clean
+	// collapses redundant separators but does NOT resolve symlinks or strip
+	// leading slashes — we have to do both explicitly.
+	name := f.Name
+	if strings.ContainsRune(name, 0) {
+		return fmt.Errorf("zip entry name contains NUL: %q", name)
+	}
+	cleaned := filepath.Clean(name)
+	if filepath.IsAbs(cleaned) || strings.HasPrefix(cleaned, "..") ||
+		strings.Contains(cleaned, string(filepath.Separator)+".."+string(filepath.Separator)) {
+		return fmt.Errorf("zip entry escapes destination: %q", name)
+	}
+
+	target := filepath.Join(dstAbs, cleaned)
+	// Defense in depth: even if the checks above missed something, this rel
+	// check guarantees target is under dstAbs.
+	rel, err := filepath.Rel(dstAbs, target)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		return fmt.Errorf("zip entry escapes destination: %q", name)
+	}
+
+	if f.FileInfo().IsDir() {
+		return os.MkdirAll(target, 0o755)
+	}
+	if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
+		return err
+	}
+
+	// Symlink support: zip entries can be symlinks (mode bit set). The
+	// lark-sec-cli artifact doesn't currently use them, but if it grows to
+	// (e.g. for shared library version aliases) we want graceful handling.
+	if f.Mode()&os.ModeSymlink != 0 {
+		rc, err := f.Open()
+		if err != nil {
+			return err
+		}
+		linkBytes, readErr := io.ReadAll(io.LimitReader(rc, 1024))
+		rc.Close()
+		if readErr != nil {
+			return readErr
+		}
+		os.Remove(target) // os.Symlink fails if target exists
+		return os.Symlink(string(linkBytes), target)
+	}
+
+	rc, err := f.Open()
+	if err != nil {
+		return err
+	}
+	defer rc.Close()
+
+	mode := f.Mode().Perm()
+	if mode == 0 {
+		mode = guessMode(cleaned)
+	}
+	out, err := os.OpenFile(target, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, mode)
+	if err != nil {
+		return err
+	}
+	if _, err := io.Copy(out, rc); err != nil {
+		out.Close()
+		return err
+	}
+	return out.Close()
+}
+
+// guessMode supplies executable bits for entries the zip writer didn't tag
+// with POSIX mode info — typically the case for archives built on Windows.
+func guessMode(name string) os.FileMode {
+	base := filepath.Base(name)
+	if base == BinaryName() {
+		return 0o755
+	}
+	ext := strings.ToLower(filepath.Ext(base))
+	switch ext {
+	case ".dylib", ".so", ".dll":
+		return 0o755
+	}
+	if runtime.GOOS != "windows" && !strings.ContainsRune(base, '.') {
+		// Plausibly an extra unix binary shipped alongside the sec-cli binary.
+		return 0o755
+	}
+	return 0o644
+}

internal/sec/archive_test.go

@@ -0,0 +1,121 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"archive/zip"
+	"bytes"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// makeZip builds an in-memory zip with the given entries, writes it to path,
+// and returns nothing — convenience for table-driven tests.
+type zipEntry struct {
+	name    string
+	body    string
+	mode    os.FileMode
+	symlink string // when set, entry is a symlink with this target
+}
+
+func makeZip(t *testing.T, path string, entries []zipEntry) {
+	t.Helper()
+	var buf bytes.Buffer
+	zw := zip.NewWriter(&buf)
+	for _, e := range entries {
+		hdr := &zip.FileHeader{Name: e.name, Method: zip.Deflate}
+		if e.mode != 0 {
+			hdr.SetMode(e.mode)
+		}
+		if e.symlink != "" {
+			hdr.SetMode(os.ModeSymlink | 0o777)
+		}
+		w, err := zw.CreateHeader(hdr)
+		if err != nil {
+			t.Fatalf("zip header %q: %v", e.name, err)
+		}
+		body := e.body
+		if e.symlink != "" {
+			body = e.symlink
+		}
+		if _, err := io.WriteString(w, body); err != nil {
+			t.Fatalf("zip write %q: %v", e.name, err)
+		}
+	}
+	if err := zw.Close(); err != nil {
+		t.Fatalf("zip close: %v", err)
+	}
+	if err := os.WriteFile(path, buf.Bytes(), 0o600); err != nil {
+		t.Fatalf("write zip: %v", err)
+	}
+}
+
+func TestExtractZip_HappyPath(t *testing.T) {
+	tmp := t.TempDir()
+	zipPath := filepath.Join(tmp, "src.zip")
+	makeZip(t, zipPath, []zipEntry{
+		{name: "lark-sec-cli", body: "binary", mode: 0o755},
+		{name: "ca.crt", body: "cert"},
+		{name: "lib/libMetaSecML.dylib", body: "dylib", mode: 0o755},
+	})
+	dst := filepath.Join(tmp, "out")
+	if err := os.MkdirAll(dst, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := ExtractZip(zipPath, dst); err != nil {
+		t.Fatalf("ExtractZip: %v", err)
+	}
+
+	for name, want := range map[string]string{
+		"lark-sec-cli":              "binary",
+		"ca.crt":                    "cert",
+		"lib/libMetaSecML.dylib":    "dylib",
+	} {
+		got, err := os.ReadFile(filepath.Join(dst, name))
+		if err != nil {
+			t.Errorf("read %s: %v", name, err)
+			continue
+		}
+		if string(got) != want {
+			t.Errorf("%s body = %q, want %q", name, got, want)
+		}
+	}
+	if info, err := os.Stat(filepath.Join(dst, "lark-sec-cli")); err == nil {
+		if info.Mode().Perm()&0o100 == 0 {
+			t.Errorf("lark-sec-cli not executable: mode=%v", info.Mode())
+		}
+	}
+}
+
+func TestExtractZip_RejectsTraversal(t *testing.T) {
+	tmp := t.TempDir()
+	zipPath := filepath.Join(tmp, "evil.zip")
+	makeZip(t, zipPath, []zipEntry{
+		{name: "../../../etc/passwd", body: "pwned"},
+	})
+	dst := filepath.Join(tmp, "out")
+	if err := os.MkdirAll(dst, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := ExtractZip(zipPath, dst); err == nil {
+		t.Fatal("ExtractZip accepted zip-slip entry")
+	}
+}
+
+func TestExtractZip_RejectsAbsolutePath(t *testing.T) {
+	tmp := t.TempDir()
+	zipPath := filepath.Join(tmp, "abs.zip")
+	makeZip(t, zipPath, []zipEntry{
+		{name: "/etc/passwd", body: "pwned"},
+	})
+	dst := filepath.Join(tmp, "out")
+	if err := os.MkdirAll(dst, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := ExtractZip(zipPath, dst); err == nil {
+		t.Fatal("ExtractZip accepted absolute-path entry")
+	}
+}

internal/sec/bootstrap.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	_ "embed"
+	"encoding/json"
+	"fmt"
+)
+
+// bootstrapManifestJSON is the lark-sec-cli release manifest shipped with this
+// lark-cli build. It points directly at TOS so a fresh install does not depend
+// on any external release-tracking service — first install is fully self-contained.
+//
+// Updating this file pins a new default version of lark-sec-cli for users who
+// install via lark-cli. After install, lark-sec-cli is in charge of finding and
+// applying its own updates; lark-cli does not consult any release server.
+//
+//go:embed bootstrap.json
+var bootstrapManifestJSON []byte
+
+// LoadBootstrap parses the embedded bootstrap manifest into a Manifest value.
+func LoadBootstrap() (*Manifest, error) {
+	var entries []Entry
+	if err := json.Unmarshal(bootstrapManifestJSON, &entries); err != nil {
+		return nil, fmt.Errorf("decode embedded bootstrap manifest: %w", err)
+	}
+	if len(entries) == 0 {
+		return nil, fmt.Errorf("embedded bootstrap manifest is empty")
+	}
+	return &Manifest{Entries: entries}, nil
+}

internal/sec/bootstrap.json

@@ -0,0 +1,59 @@
+[
+  {
+    "key": 0,
+    "buildPlatform": "linux",
+    "urls": [
+      {
+        "urls": {
+          "amd64": "https://lf3-cdn-tos.bytegoofy.com/obj/tron-demo/lark-sec-cli/releases/1.0.1-alpha.23/367354993/linux-amd64/linux-amd64-1.0.1-alpha.23.zip",
+          "arm64": "https://lf3-cdn-tos.bytegoofy.com/obj/tron-demo/lark-sec-cli/releases/1.0.1-alpha.23/367354993/linux-arm64/linux-arm64-1.0.1-alpha.23.zip"
+        },
+        "region": "cn"
+      }
+    ],
+    "branch": "dev",
+    "version": "1.0.1-alpha.23",
+    "extra": {
+      "pipeline_id": "367354993",
+      "upload_date": 1778487420795
+    }
+  },
+  {
+    "key": 1,
+    "buildPlatform": "win32",
+    "urls": [
+      {
+        "urls": {
+          "x86": "https://lf3-cdn-tos.bytegoofy.com/obj/tron-demo/lark-sec-cli/releases/1.0.1-alpha.23/367354993/windows-386/windows-386-1.0.1-alpha.23.zip",
+          "amd64": "https://lf3-cdn-tos.bytegoofy.com/obj/tron-demo/lark-sec-cli/releases/1.0.1-alpha.23/367354993/windows-amd64/windows-amd64-1.0.1-alpha.23.zip"
+        },
+        "region": "cn"
+      }
+    ],
+    "branch": "dev",
+    "version": "1.0.1-alpha.23",
+    "extra": {
+      "pipeline_id": "367354993",
+      "upload_date": 1778487437393
+    }
+  },
+  {
+    "key": 2,
+    "buildPlatform": "darwin",
+    "urls": [
+      {
+        "urls": {
+          "amd64": "https://lf3-cdn-tos.bytegoofy.com/obj/tron-demo/lark-sec-cli/releases/1.0.1-alpha.23/367354993/darwin-amd64/darwin-amd64-1.0.1-alpha.23.zip",
+          "arm64": "https://lf3-cdn-tos.bytegoofy.com/obj/tron-demo/lark-sec-cli/releases/1.0.1-alpha.23/367354993/darwin-arm64/darwin-arm64-1.0.1-alpha.23.zip"
+        },
+        "region": "cn"
+      }
+    ],
+    "branch": "dev",
+    "version": "1.0.1-alpha.23",
+    "extra": {
+      "pipeline_id": "367354993",
+      "upload_date": 1778487395152
+    }
+  }
+]

internal/sec/bootstrap_test.go

@@ -0,0 +1,58 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"runtime"
+	"strings"
+	"testing"
+)
+
+// TestLoadBootstrap_DecodesAllPlatforms guards against the embedded
+// manifest becoming malformed or losing an OS — both would break first
+// install on whatever GOOS lost its entry.
+func TestLoadBootstrap_DecodesAllPlatforms(t *testing.T) {
+	manifest, err := LoadBootstrap()
+	if err != nil {
+		t.Fatalf("LoadBootstrap: %v", err)
+	}
+	platforms := map[string]bool{}
+	for _, e := range manifest.Entries {
+		platforms[e.BuildPlatform] = true
+		if e.Version == "" {
+			t.Errorf("entry %s missing version", e.BuildPlatform)
+		}
+		if e.Extra.PipelineID == "" {
+			t.Errorf("entry %s missing extra.pipeline_id", e.BuildPlatform)
+		}
+	}
+	for _, want := range []string{"darwin", "linux", "win32"} {
+		if !platforms[want] {
+			t.Errorf("bootstrap missing platform %q", want)
+		}
+	}
+}
+
+// TestLoadBootstrap_PickArtifactForCurrentHost ensures the embedded manifest
+// resolves to a real URL for whatever platform the test runner is on, so a
+// developer fixing this code locally can still smoke-test their changes.
+func TestLoadBootstrap_PickArtifactForCurrentHost(t *testing.T) {
+	manifest, err := LoadBootstrap()
+	if err != nil {
+		t.Fatalf("LoadBootstrap: %v", err)
+	}
+	art, err := manifest.PickArtifact(runtime.GOOS, runtime.GOARCH, "cn")
+	if err != nil {
+		t.Fatalf("PickArtifact for %s/%s: %v", runtime.GOOS, runtime.GOARCH, err)
+	}
+	if !strings.HasPrefix(art.URL, "https://") {
+		t.Errorf("URL is not https: %q", art.URL)
+	}
+	if !strings.HasSuffix(art.URL, ".zip") {
+		t.Errorf("URL is not a .zip: %q", art.URL)
+	}
+	if art.BuildID == "" {
+		t.Error("BuildID is empty")
+	}
+}

internal/sec/download.go

@@ -0,0 +1,156 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"context"
+	"crypto/md5"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"hash"
+	"io"
+	"net/http"
+	"os"
+)
+
+// downloadMaxBytes caps the artifact size we'll accept. Comfortably over the
+// real lark-sec-cli zip (~tens of MB) and well under what a malicious mirror
+// could use to exhaust local disk before we noticed.
+const downloadMaxBytes = 512 * 1024 * 1024
+
+// DownloadOptions controls Download.
+type DownloadOptions struct {
+	URL         string
+	Destination string // full path to the .zip we'll create
+	HTTPClient  *http.Client
+
+	// ExpectedSHA256, if non-empty, is the hex SHA256 the artifact MUST
+	// match — verified after the full body has been streamed. Use this when
+	// the manifest publishes a hash for the artifact (e.g. bootstrap.json's
+	// `extra.sha256`). Any mismatch fails the download with the .part file
+	// removed.
+	//
+	// When empty (the manifest doesn't carry a hash), the only integrity
+	// check left is the CDN's own `Content-MD5` response header, applied
+	// opportunistically below.
+	ExpectedSHA256 string
+}
+
+// Download streams URL to Destination. Writes to a sibling .part file and
+// renames into place on success so a crashed or aborted run leaves no
+// half-written zip the next run might mistake for valid.
+//
+// Two layers of integrity check, both opt-in:
+//
+//  1. ExpectedSHA256 (strong, manifest-provided): cryptographic, fails the
+//     download on mismatch. Use whenever the release manifest carries a hash.
+//  2. CDN `Content-MD5` header (opportunistic): non-cryptographic, catches
+//     edge replacement or transit corruption when the upstream CDN populates
+//     the header. Runs unconditionally — if the header is present we honour it.
+//
+// Neither check defends against a malicious upstream that controls both the
+// artifact AND the manifest. That class of risk has to be handled by signing
+// the release pipeline, which is out of scope for the client.
+func Download(ctx context.Context, opts DownloadOptions) error {
+	if opts.HTTPClient == nil {
+		return fmt.Errorf("Download: HTTPClient is required")
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, opts.URL, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := opts.HTTPClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("download %s: %w", opts.URL, err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download %s: status %d", opts.URL, resp.StatusCode)
+	}
+
+	tmpPath := opts.Destination + ".part"
+	out, err := os.OpenFile(tmpPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o600)
+	if err != nil {
+		return err
+	}
+	cleanup := func() { out.Close(); os.Remove(tmpPath) }
+
+	// Hash both ways during the single read pass. Both hashers are cheap and
+	// we don't know yet which check (or both) we'll actually need.
+	sha := sha256.New()
+	md := md5.New()
+	writer := io.MultiWriter(out, sha, md)
+
+	n, err := io.Copy(writer, io.LimitReader(resp.Body, downloadMaxBytes+1))
+	if err != nil {
+		cleanup()
+		return fmt.Errorf("download %s: %w", opts.URL, err)
+	}
+	if n > downloadMaxBytes {
+		cleanup()
+		return fmt.Errorf("download %s: exceeds %d bytes", opts.URL, downloadMaxBytes)
+	}
+	if err := out.Sync(); err != nil {
+		cleanup()
+		return err
+	}
+	if err := out.Close(); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+
+	if err := verifyChecksums(resp, opts.ExpectedSHA256, sha, md); err != nil {
+		os.Remove(tmpPath)
+		return fmt.Errorf("download %s: %w", opts.URL, err)
+	}
+
+	if err := os.Rename(tmpPath, opts.Destination); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+	return nil
+}
+
+// verifyChecksums applies the two-layer integrity check after the body has
+// been fully streamed. Returns nil when both layers (whichever apply) agree.
+func verifyChecksums(resp *http.Response, expectedSHA256 string, sha, md hash.Hash) error {
+	if expectedSHA256 != "" {
+		got := hex.EncodeToString(sha.Sum(nil))
+		if !equalFoldHex(got, expectedSHA256) {
+			return fmt.Errorf("sha256 mismatch: expected %s, got %s", expectedSHA256, got)
+		}
+	}
+
+	if cdnMD5 := resp.Header.Get("Content-MD5"); cdnMD5 != "" {
+		got := base64.StdEncoding.EncodeToString(md.Sum(nil))
+		if got != cdnMD5 {
+			return fmt.Errorf("content-md5 mismatch: cdn=%s, computed=%s", cdnMD5, got)
+		}
+	}
+	return nil
+}
+
+// equalFoldHex is a non-allocating ASCII case-insensitive compare for hex
+// strings. SHA256 manifests sometimes ship uppercase, sometimes lowercase.
+func equalFoldHex(a, b string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := 0; i < len(a); i++ {
+		ca, cb := a[i], b[i]
+		if 'A' <= ca && ca <= 'Z' {
+			ca += 'a' - 'A'
+		}
+		if 'A' <= cb && cb <= 'Z' {
+			cb += 'a' - 'A'
+		}
+		if ca != cb {
+			return false
+		}
+	}
+	return true
+}

internal/sec/download_test.go

@@ -0,0 +1,184 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"context"
+	"crypto/md5"
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/hex"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+const bodyContent = "lark-sec-cli pretend zip bytes"
+
+// fixtureSHA256 / fixtureMD5 are the hashes of bodyContent.
+var fixtureSHA256 string
+var fixtureMD5b64 string
+
+func init() {
+	sum := sha256.Sum256([]byte(bodyContent))
+	fixtureSHA256 = hex.EncodeToString(sum[:])
+	m := md5.Sum([]byte(bodyContent))
+	fixtureMD5b64 = base64.StdEncoding.EncodeToString(m[:])
+}
+
+func newFixtureServer(t *testing.T, setContentMD5 bool) *httptest.Server {
+	t.Helper()
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if setContentMD5 {
+			w.Header().Set("Content-MD5", fixtureMD5b64)
+		}
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte(bodyContent))
+	}))
+}
+
+// TestDownload_HappyPath_NoChecksum confirms that a download with no manifest
+// SHA and no CDN MD5 succeeds — the integrity hooks are opt-in, not required.
+func TestDownload_HappyPath_NoChecksum(t *testing.T) {
+	srv := newFixtureServer(t, false)
+	defer srv.Close()
+
+	dst := filepath.Join(t.TempDir(), "out.zip")
+	err := Download(context.Background(), DownloadOptions{
+		URL:         srv.URL,
+		Destination: dst,
+		HTTPClient:  srv.Client(),
+	})
+	if err != nil {
+		t.Fatalf("Download: %v", err)
+	}
+	got, err := os.ReadFile(dst)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(got) != bodyContent {
+		t.Errorf("body roundtrip mismatch")
+	}
+}
+
+// TestDownload_SHA256_Match confirms the manifest-provided SHA256 path
+// passes for a correct hash. Tests both cases (with and without CDN MD5)
+// so the second layer doesn't interfere.
+func TestDownload_SHA256_Match(t *testing.T) {
+	for _, withMD5 := range []bool{false, true} {
+		name := "noMD5"
+		if withMD5 {
+			name = "withCDNMd5"
+		}
+		t.Run(name, func(t *testing.T) {
+			srv := newFixtureServer(t, withMD5)
+			defer srv.Close()
+			dst := filepath.Join(t.TempDir(), "out.zip")
+			err := Download(context.Background(), DownloadOptions{
+				URL:            srv.URL,
+				Destination:    dst,
+				HTTPClient:     srv.Client(),
+				ExpectedSHA256: fixtureSHA256,
+			})
+			if err != nil {
+				t.Fatalf("Download: %v", err)
+			}
+		})
+	}
+}
+
+// TestDownload_SHA256_Mismatch is the safety property: a wrong manifest hash
+// rejects the download AND removes the .part file so the next run doesn't
+// pick up a poisoned zip.
+func TestDownload_SHA256_Mismatch(t *testing.T) {
+	srv := newFixtureServer(t, false)
+	defer srv.Close()
+
+	dst := filepath.Join(t.TempDir(), "out.zip")
+	err := Download(context.Background(), DownloadOptions{
+		URL:            srv.URL,
+		Destination:    dst,
+		HTTPClient:     srv.Client(),
+		ExpectedSHA256: "0000000000000000000000000000000000000000000000000000000000000000",
+	})
+	if err == nil {
+		t.Fatal("expected sha256 mismatch error")
+	}
+	if !strings.Contains(err.Error(), "sha256 mismatch") {
+		t.Errorf("error should mention sha256 mismatch: %v", err)
+	}
+	if _, statErr := os.Stat(dst); statErr == nil {
+		t.Errorf("dst should not exist after mismatch")
+	}
+	if _, statErr := os.Stat(dst + ".part"); statErr == nil {
+		t.Errorf(".part should not exist after mismatch")
+	}
+}
+
+// TestDownload_ContentMD5_Mismatch confirms the opportunistic check fires
+// even when no manifest SHA was provided. Catches a CDN edge that returned
+// content but a stale/wrong Content-MD5 header (or a poisoned proxy).
+func TestDownload_ContentMD5_Mismatch(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-MD5", "Z3JhZmFuYTpyZWFsbHk/Pz8/Pz8/PzA9PT0=") // arbitrary
+		_, _ = w.Write([]byte(bodyContent))
+	}))
+	defer srv.Close()
+
+	dst := filepath.Join(t.TempDir(), "out.zip")
+	err := Download(context.Background(), DownloadOptions{
+		URL:         srv.URL,
+		Destination: dst,
+		HTTPClient:  srv.Client(),
+	})
+	if err == nil {
+		t.Fatal("expected content-md5 mismatch error")
+	}
+	if !strings.Contains(err.Error(), "content-md5 mismatch") {
+		t.Errorf("error should mention content-md5 mismatch: %v", err)
+	}
+}
+
+// TestDownload_SHA256_CaseInsensitive guards the hex compare against case
+// drift in the manifest (some publishers upper-case).
+func TestDownload_SHA256_CaseInsensitive(t *testing.T) {
+	srv := newFixtureServer(t, false)
+	defer srv.Close()
+
+	dst := filepath.Join(t.TempDir(), "out.zip")
+	err := Download(context.Background(), DownloadOptions{
+		URL:            srv.URL,
+		Destination:    dst,
+		HTTPClient:     srv.Client(),
+		ExpectedSHA256: strings.ToUpper(fixtureSHA256),
+	})
+	if err != nil {
+		t.Fatalf("Download (uppercase sha): %v", err)
+	}
+}
+
+// TestDownload_404_NoPartFile confirms that a non-200 response leaves no
+// .part file behind to confuse the next attempt.
+func TestDownload_404_NoPartFile(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer srv.Close()
+
+	dst := filepath.Join(t.TempDir(), "out.zip")
+	err := Download(context.Background(), DownloadOptions{
+		URL:         srv.URL,
+		Destination: dst,
+		HTTPClient:  srv.Client(),
+	})
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+	if _, statErr := os.Stat(dst + ".part"); statErr == nil {
+		t.Errorf(".part should not exist after 404")
+	}
+}

internal/sec/install.go

@@ -0,0 +1,297 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/larksuite/cli/internal/client"
+)
+
+// Installer orchestrates first-time install of lark-sec-cli:
+// fetch remote manifest via OAPI → download zip → extract into
+// versions/<version>/ → swap "current" → write state.json.
+//
+// After this first install, lark-sec-cli takes over its own updates and
+// lark-cli is no longer in the update path. The installer therefore only
+// knows about the bootstrap path — no Tron, no other release sources.
+type Installer struct {
+	Paths      *Paths
+	HTTPClient *http.Client
+	// APIClientFunc resolves the OAPI client lazily. It is invoked only when
+	// the install pipeline actually needs to fetch the remote manifest —
+	// short-circuits (and other callers of installer() that don't install,
+	// like sec status / sec stop) avoid keychain decryption entirely.
+	APIClientFunc func() (*client.APIClient, error)
+}
+
+// InstallOptions tunes a single Install call.
+type InstallOptions struct {
+	// Force re-runs the pipeline even when an install already exists. Used by
+	// `sec install --force` for repair / re-pinning to the bundled bootstrap.
+	Force bool
+	// Region selects which region's URLs to pick from the manifest. Defaults to
+	// DefaultRegion ("cn"). Reserved for future brand split.
+	Region string
+	// Verbose, when non-nil, is the destination for step-by-step trace output.
+	// nil = silent (production default); typically set to stderr by `sec install -v`.
+	Verbose io.Writer
+}
+
+// tracef writes one trace line to w if w is non-nil.
+func tracef(w io.Writer, format string, args ...any) {
+	if w == nil {
+		return
+	}
+	fmt.Fprintf(w, "[sec install] "+format+"\n", args...)
+}
+
+// Install runs the bootstrap pipeline and returns the new State on success.
+// If a usable install already exists on disk and Force is false, returns the
+// existing state unchanged (no network call).
+func (i *Installer) Install(ctx context.Context, opts InstallOptions) (*State, error) {
+	v := opts.Verbose
+	tracef(v, "ensuring sec paths under %s", i.Paths.InstallDir())
+	if err := i.Paths.Ensure(); err != nil {
+		return nil, err
+	}
+
+	tracef(v, "loading existing state from %s", i.Paths.StateFile())
+	existing, err := LoadState(i.Paths.StateFile())
+	if err != nil {
+		return nil, fmt.Errorf("load sec state: %w", err)
+	}
+	if existing != nil {
+		tracef(v, "existing state: version=%s binary=%s", existing.Version, existing.BinaryPath)
+	} else {
+		tracef(v, "no existing state on disk")
+	}
+
+	// Idempotent short-circuit: nothing to do if an install is already on disk.
+	// Self-upgrades after bootstrap are lark-sec-cli's job, not ours — see the
+	// upgrade subsystem in lark-sec-cli/internal/upgrade/.
+	if !opts.Force && existing != nil && binaryReady(existing.BinaryPath) {
+		tracef(v, "binary exists at %s — short-circuiting (no network)", existing.BinaryPath)
+		return existing, nil
+	}
+	if opts.Force {
+		tracef(v, "--force set; running full install pipeline")
+	} else {
+		tracef(v, "no usable install on disk; running full install pipeline")
+	}
+
+	region := opts.Region
+	if region == "" {
+		region = DefaultRegion
+	}
+	tracef(v, "region=%s", region)
+
+	if i.APIClientFunc == nil {
+		return nil, errors.New("sec installer: APIClientFunc is required to fetch remote manifest")
+	}
+	tracef(v, "resolving OAPI client (will decrypt credentials)")
+	apiClient, err := i.APIClientFunc()
+	if err != nil {
+		return nil, fmt.Errorf("resolve api client: %w", err)
+	}
+	platform, arch, err := CurrentPlatformArch()
+	if err != nil {
+		return nil, err
+	}
+	tracef(v, "detected platform=%s arch=%s", platform, arch)
+
+	tracef(v, "fetching remote manifest from %s", secCliManifestPath)
+	rm, err := FetchRemoteManifest(ctx, apiClient, region, platform, arch, v)
+	if err != nil {
+		return nil, err
+	}
+	tracef(v, "manifest returned %d url(s): %v", len(rm.URLs), rm.URLs)
+	downloadURL := rm.URLs[0]
+	tracef(v, "picked downloadURL=%s", downloadURL)
+	version, err := versionFromURL(downloadURL)
+	if err != nil {
+		return nil, err
+	}
+	tracef(v, "parsed version=%s", version)
+
+	versionDir := i.Paths.VersionDir(version)
+	tracef(v, "creating versionDir=%s", versionDir)
+	if err := os.MkdirAll(versionDir, 0o755); err != nil {
+		return nil, err
+	}
+	zipPath := filepath.Join(i.Paths.VersionsDir(), version+".zip")
+
+	tracef(v, "downloading %s -> %s", downloadURL, zipPath)
+	if err := Download(ctx, DownloadOptions{
+		URL:         downloadURL,
+		Destination: zipPath,
+		HTTPClient:  i.HTTPClient,
+	}); err != nil {
+		return nil, err
+	}
+	if info, statErr := os.Stat(zipPath); statErr == nil {
+		tracef(v, "downloaded %d bytes", info.Size())
+	}
+	defer os.Remove(zipPath) // free disk; we keep the unpacked version dir
+
+	tracef(v, "extracting %s -> %s", zipPath, versionDir)
+	if err := ExtractZip(zipPath, versionDir); err != nil {
+		return nil, err
+	}
+
+	binaryPath, err := locateBinary(versionDir)
+	if err != nil {
+		return nil, err
+	}
+	tracef(v, "located binary at %s", binaryPath)
+	// Ensure executable bit on POSIX — some zips lose it.
+	if runtime.GOOS != "windows" {
+		if info, err := os.Stat(binaryPath); err == nil {
+			_ = os.Chmod(binaryPath, info.Mode()|0o100|0o010|0o001)
+		}
+	}
+
+	tracef(v, "swapping %s -> %s", i.Paths.CurrentLink(), versionDir)
+	if err := swapCurrent(i.Paths.CurrentLink(), versionDir); err != nil {
+		return nil, fmt.Errorf("swap current: %w", err)
+	}
+
+	tracef(v, "writing state.json to %s", i.Paths.StateFile())
+	state := &State{
+		Version:     version,
+		InstalledAt: time.Now().UTC(),
+		BinaryPath:  i.Paths.BinaryPath(),
+	}
+	if err := SaveState(i.Paths.StateFile(), state); err != nil {
+		return nil, err
+	}
+	return state, nil
+}
+
+// locateBinary handles two artifact layouts: flat (zip root has the binary)
+// and nested (zip root is a single dir containing the binary). The bootstrap
+// manifest's example payload uses nested ("linux-amd64-1.0.1-alpha.23/...");
+// we accommodate either since the wrapping dir name could change per build.
+func locateBinary(versionDir string) (string, error) {
+	name := BinaryName()
+
+	flat := filepath.Join(versionDir, name)
+	if _, err := os.Stat(flat); err == nil {
+		return flat, nil
+	}
+
+	var found string
+	walkErr := filepath.WalkDir(versionDir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if !d.IsDir() && d.Name() == name {
+			found = path
+			return fs.SkipAll
+		}
+		return nil
+	})
+	if walkErr != nil {
+		return "", walkErr
+	}
+	if found == "" {
+		return "", fmt.Errorf("binary %q not found under %s", name, versionDir)
+	}
+
+	// Promote the binary's parent to be versionDir so "current" → versionDir
+	// produces a predictable layout. Move the *contents* up rather than the
+	// binary alone, because shared libs may sit beside it.
+	parent := filepath.Dir(found)
+	if parent != versionDir {
+		entries, err := os.ReadDir(parent)
+		if err != nil {
+			return "", err
+		}
+		for _, e := range entries {
+			if err := os.Rename(filepath.Join(parent, e.Name()), filepath.Join(versionDir, e.Name())); err != nil {
+				return "", err
+			}
+		}
+		_ = os.Remove(parent)
+	}
+	return filepath.Join(versionDir, name), nil
+}
+
+// swapCurrent atomically points <install>/current at versionDir. On POSIX
+// we use a symlink with the standard rename-into-place trick; on Windows we
+// fall back to removing the directory and copying, since junctions need
+// admin / developer-mode privileges we may not have.
+func swapCurrent(link, versionDir string) error {
+	if runtime.GOOS == "windows" {
+		// Remove any existing target then copy. This is non-atomic, but
+		// concurrent installs on the same Windows host are not a use case
+		// we support — `sec install` runs interactively.
+		if err := os.RemoveAll(link); err != nil && !errors.Is(err, os.ErrNotExist) {
+			return err
+		}
+		return copyDir(versionDir, link)
+	}
+
+	tmp := link + ".new"
+	_ = os.Remove(tmp)
+	if err := os.Symlink(versionDir, tmp); err != nil {
+		return err
+	}
+	return os.Rename(tmp, link)
+}
+
+func copyDir(src, dst string) error {
+	if err := os.MkdirAll(dst, 0o755); err != nil {
+		return err
+	}
+	return filepath.WalkDir(src, func(p string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		rel, err := filepath.Rel(src, p)
+		if err != nil {
+			return err
+		}
+		target := filepath.Join(dst, rel)
+		if d.IsDir() {
+			return os.MkdirAll(target, 0o755)
+		}
+		info, err := d.Info()
+		if err != nil {
+			return err
+		}
+		in, err := os.Open(p)
+		if err != nil {
+			return err
+		}
+		defer in.Close()
+		out, err := os.OpenFile(target, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, info.Mode().Perm())
+		if err != nil {
+			return err
+		}
+		_, copyErr := io.Copy(out, in)
+		closeErr := out.Close()
+		if copyErr != nil {
+			return copyErr
+		}
+		return closeErr
+	})
+}
+
+func binaryReady(path string) bool {
+	if path == "" {
+		return false
+	}
+	info, err := os.Stat(path)
+	return err == nil && !info.IsDir()
+}

internal/sec/manifest.go

@@ -0,0 +1,139 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"fmt"
+	"runtime"
+)
+
+// Manifest describes a lark-sec-cli release set: one Entry per build platform,
+// each carrying one or more region-scoped URL maps keyed by arch. It's what we
+// embed at build time as the bootstrap manifest. After bootstrap, lark-sec-cli
+// queries its own release source for updates — lark-cli is uninvolved.
+type Manifest struct {
+	Entries []Entry
+}
+
+// Entry is one row of the bootstrap manifest, one per published platform.
+type Entry struct {
+	Key           int          `json:"key"`
+	BuildPlatform string       `json:"buildPlatform"` // "darwin" | "linux" | "win32"
+	URLs          []RegionURLs `json:"urls"`
+	Branch        string       `json:"branch"`
+	Version       string       `json:"version"`
+	Extra         EntryExtra   `json:"extra"`
+}
+
+// RegionURLs maps an arch ("amd64", "arm64", "x86") to its download URL,
+// scoped to a region ("cn" today; reserved for future brand split).
+type RegionURLs struct {
+	URLs   map[string]string `json:"urls"`
+	Region string            `json:"region"`
+}
+
+// EntryExtra is metadata the release pipeline emits alongside each artifact.
+// PipelineID is the build identifier lark-sec-cli will later forward to its
+// own update server when checking for new versions. SHA256 (when present) is
+// the hex-encoded hash of the zip artifact; the installer fails the download
+// on mismatch. Manifests built before the release pipeline added the field
+// leave it empty, in which case integrity falls back to the CDN's own
+// Content-MD5 header.
+type EntryExtra struct {
+	PipelineID string `json:"pipeline_id"`
+	UploadDate int64  `json:"upload_date"`
+	SHA256     string `json:"sha256,omitempty"`
+}
+
+// Artifact is the resolved download target after platform/arch/region selection.
+type Artifact struct {
+	URL     string
+	Version string
+	BuildID string // pipeline_id — recorded in state.json so lark-sec-cli knows what it was installed at
+	SHA256  string // hex-encoded; empty when the manifest doesn't carry one
+}
+
+// PickArtifact selects the right Entry for the current GOOS/GOARCH and the
+// requested region. Returns a clear error explaining which combination was
+// missing so users can tell whether the build was never published or just not
+// for their platform.
+func (m *Manifest) PickArtifact(goos, goarch, region string) (*Artifact, error) {
+	platform, err := platformKey(goos)
+	if err != nil {
+		return nil, err
+	}
+	arch, err := archKey(goos, goarch)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, e := range m.Entries {
+		if e.BuildPlatform != platform {
+			continue
+		}
+		for _, ru := range e.URLs {
+			if ru.Region != region {
+				continue
+			}
+			url, ok := ru.URLs[arch]
+			if !ok || url == "" {
+				continue
+			}
+			return &Artifact{
+				URL:     url,
+				Version: e.Version,
+				BuildID: e.Extra.PipelineID,
+				SHA256:  e.Extra.SHA256,
+			}, nil
+		}
+	}
+	return nil, fmt.Errorf("no artifact for platform=%s arch=%s region=%s", platform, arch, region)
+}
+
+// platformKey maps Go's GOOS to the manifest's buildPlatform enum.
+func platformKey(goos string) (string, error) {
+	switch goos {
+	case "darwin":
+		return "darwin", nil
+	case "linux":
+		return "linux", nil
+	case "windows":
+		return "win32", nil
+	default:
+		return "", fmt.Errorf("unsupported GOOS: %s", goos)
+	}
+}
+
+// archKey maps Go's GOARCH to the arch key the manifest uses inside RegionURLs.URLs.
+// Windows 32-bit ships under "x86" while POSIX 32-bit (e.g. 386 on linux) is not
+// currently published — surface that as an error rather than silently falling back.
+func archKey(goos, goarch string) (string, error) {
+	switch goarch {
+	case "amd64":
+		return "amd64", nil
+	case "arm64":
+		return "arm64", nil
+	case "386":
+		if goos == "windows" {
+			return "x86", nil
+		}
+		return "", fmt.Errorf("32-bit %s is not published", goos)
+	default:
+		return "", fmt.Errorf("unsupported GOARCH: %s", goarch)
+	}
+}
+
+// CurrentPlatformArch is a convenience for the install flow.
+func CurrentPlatformArch() (platform, arch string, err error) {
+	platform, err = platformKey(runtime.GOOS)
+	if err != nil {
+		return "", "", err
+	}
+	arch, err = archKey(runtime.GOOS, runtime.GOARCH)
+	return platform, arch, err
+}
+
+// DefaultRegion is the only region published today for bootstrap installs.
+// Kept here for callers that still want a single source of truth.
+const DefaultRegion = "cn"

internal/sec/manifest_test.go

@@ -0,0 +1,108 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"testing"
+)
+
+// sampleManifest is the manifest example baked into bootstrap.json, trimmed to
+// the three published platforms. PickArtifact must select the right URL for
+// each GOOS/GOARCH combination.
+func sampleManifest() *Manifest {
+	return &Manifest{Entries: []Entry{
+		{
+			Key:           0,
+			BuildPlatform: "linux",
+			Branch:        "dev",
+			Version:       "1.0.1-alpha.23",
+			Extra:         EntryExtra{PipelineID: "367354993"},
+			URLs: []RegionURLs{{
+				Region: "cn",
+				URLs: map[string]string{
+					"amd64": "https://cdn/linux-amd64.zip",
+					"arm64": "https://cdn/linux-arm64.zip",
+				},
+			}},
+		},
+		{
+			Key:           1,
+			BuildPlatform: "win32",
+			Branch:        "dev",
+			Version:       "1.0.1-alpha.23",
+			Extra:         EntryExtra{PipelineID: "367354993"},
+			URLs: []RegionURLs{{
+				Region: "cn",
+				URLs: map[string]string{
+					"x86":   "https://cdn/win-386.zip",
+					"amd64": "https://cdn/win-amd64.zip",
+				},
+			}},
+		},
+		{
+			Key:           2,
+			BuildPlatform: "darwin",
+			Branch:        "dev",
+			Version:       "1.0.1-alpha.23",
+			Extra:         EntryExtra{PipelineID: "367354993"},
+			URLs: []RegionURLs{{
+				Region: "cn",
+				URLs: map[string]string{
+					"amd64": "https://cdn/darwin-amd64.zip",
+					"arm64": "https://cdn/darwin-arm64.zip",
+				},
+			}},
+		},
+	}}
+}
+
+func TestPickArtifact_HappyPath(t *testing.T) {
+	m := sampleManifest()
+	cases := []struct {
+		goos, goarch string
+		wantURL      string
+	}{
+		{"darwin", "arm64", "https://cdn/darwin-arm64.zip"},
+		{"darwin", "amd64", "https://cdn/darwin-amd64.zip"},
+		{"linux", "amd64", "https://cdn/linux-amd64.zip"},
+		{"linux", "arm64", "https://cdn/linux-arm64.zip"},
+		{"windows", "amd64", "https://cdn/win-amd64.zip"},
+		{"windows", "386", "https://cdn/win-386.zip"},
+	}
+	for _, c := range cases {
+		t.Run(c.goos+"/"+c.goarch, func(t *testing.T) {
+			art, err := m.PickArtifact(c.goos, c.goarch, "cn")
+			if err != nil {
+				t.Fatalf("PickArtifact: %v", err)
+			}
+			if art.URL != c.wantURL {
+				t.Errorf("URL = %q, want %q", art.URL, c.wantURL)
+			}
+			if art.Version != "1.0.1-alpha.23" {
+				t.Errorf("Version = %q", art.Version)
+			}
+			if art.BuildID != "367354993" {
+				t.Errorf("BuildID = %q", art.BuildID)
+			}
+		})
+	}
+}
+
+func TestPickArtifact_Linux386Rejected(t *testing.T) {
+	if _, err := sampleManifest().PickArtifact("linux", "386", "cn"); err == nil {
+		t.Fatal("expected error for linux/386 (not published)")
+	}
+}
+
+func TestPickArtifact_UnknownRegion(t *testing.T) {
+	if _, err := sampleManifest().PickArtifact("darwin", "arm64", "sg"); err == nil {
+		t.Fatal("expected error for region=sg (not present in fixture)")
+	}
+}
+
+func TestPickArtifact_UnsupportedOS(t *testing.T) {
+	if _, err := sampleManifest().PickArtifact("plan9", "amd64", "cn"); err == nil {
+		t.Fatal("expected error for plan9")
+	}
+}

internal/sec/paths.go

@@ -0,0 +1,146 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+// Package sec manages the first-time bootstrap install of the lark-sec-cli
+// sidecar from lark-cli's side: download the artifact, lay it out on disk,
+// record what version landed. Runtime lifecycle (start / stop / status) is
+// handled by shelling out to lark-sec-cli's own `service enable / disable /
+// status` commands, so we don't need pid files / env capture / log tees here.
+// Updates after install are lark-sec-cli's responsibility, not lark-cli's.
+package sec
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"runtime"
+)
+
+const (
+	// envInstallDirOverride lets tests and power users redirect the entire sec
+	// tree (install + data) to a single root. When set, install_dir is <root>
+	// and data_dir is <root>/data — no platform-conventional lookup happens.
+	envInstallDirOverride = "LARKSUITE_CLI_SEC_DIR"
+)
+
+// BinaryName returns the executable basename inside the sec-cli artifact for
+// the current platform:
+//
+//	darwin  → libLarkEntCli.dylib
+//	linux   → liblarkentcli.so
+//	windows → lark_enterprise_cli.exe
+//
+// The .dylib/.so extensions on POSIX are convention only — those files are
+// normal Mach-O / ELF executables, not loadable libraries.
+func BinaryName() string {
+	switch runtime.GOOS {
+	case "darwin":
+		return "libLarkEntCli.dylib"
+	case "windows":
+		return "lark_enterprise_cli.exe"
+	default:
+		return "liblarkentcli.so"
+	}
+}
+
+// Paths exposes the filesystem layout for the sec sidecar. All methods return
+// absolute paths; nothing on disk is created — callers must call Ensure().
+type Paths struct {
+	install string
+	data    string
+}
+
+// DefaultPaths returns Paths rooted at the platform-conventional user data dir,
+// or at $LARKSUITE_CLI_SEC_DIR when set.
+func DefaultPaths() (*Paths, error) {
+	if root := os.Getenv(envInstallDirOverride); root != "" {
+		return &Paths{install: root, data: filepath.Join(root, "data")}, nil
+	}
+	install, data, err := platformDirs()
+	if err != nil {
+		return nil, err
+	}
+	return &Paths{install: install, data: data}, nil
+}
+
+// platformDirs returns (install_dir, data_dir) for the current OS, applying
+// per-platform conventions:
+//
+//	macOS    install = data = ~/Library/Application Support/lark-cli/sec
+//	Linux    install = $XDG_DATA_HOME/lark-cli/sec      (fallback ~/.local/share/...)
+//	         data    = $XDG_STATE_HOME/lark-cli/sec     (fallback ~/.local/state/...)
+//	Windows  install = data = %LOCALAPPDATA%\lark-cli\sec
+//
+// Linux splits install/data along XDG lines; macOS and Windows colocate them
+// because their conventions don't distinguish "share" from "state" at the
+// per-user level.
+func platformDirs() (install, data string, err error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", "", err
+	}
+	switch runtime.GOOS {
+	case "darwin":
+		base := filepath.Join(home, "Library", "Application Support", "lark-cli", "sec")
+		return base, filepath.Join(base, "data"), nil
+	case "windows":
+		appData := os.Getenv("LOCALAPPDATA")
+		if appData == "" {
+			return "", "", errors.New("LOCALAPPDATA is not set")
+		}
+		base := filepath.Join(appData, "lark-cli", "sec")
+		return base, filepath.Join(base, "data"), nil
+	case "linux":
+		dataHome := os.Getenv("XDG_DATA_HOME")
+		if dataHome == "" {
+			dataHome = filepath.Join(home, ".local", "share")
+		}
+		stateHome := os.Getenv("XDG_STATE_HOME")
+		if stateHome == "" {
+			stateHome = filepath.Join(home, ".local", "state")
+		}
+		return filepath.Join(dataHome, "lark-cli", "sec"),
+			filepath.Join(stateHome, "lark-cli", "sec"),
+			nil
+	default:
+		base := filepath.Join(home, ".lark-cli", "sec")
+		return base, filepath.Join(base, "data"), nil
+	}
+}
+
+// Ensure creates the directories the installer writes into.
+func (p *Paths) Ensure() error {
+	for _, d := range []string{p.install, p.data, p.VersionsDir()} {
+		if err := os.MkdirAll(d, 0o700); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// InstallDir is the root for binaries and version trees.
+func (p *Paths) InstallDir() string { return p.install }
+
+// DataDir is the root for state.json (and anything else lark-cli persists
+// about the install — currently just state.json).
+func (p *Paths) DataDir() string { return p.data }
+
+// VersionsDir stores each unpacked release: versions/<version>/<files>.
+func (p *Paths) VersionsDir() string { return filepath.Join(p.install, "versions") }
+
+// VersionDir is the unpack target for a specific version string.
+func (p *Paths) VersionDir(version string) string {
+	return filepath.Join(p.VersionsDir(), version)
+}
+
+// CurrentLink points to the active version (symlink on POSIX, plain copy on Windows).
+func (p *Paths) CurrentLink() string { return filepath.Join(p.install, "current") }
+
+// BinaryPath is the active sec-cli executable, addressed through the
+// `current` symlink so it stays valid across version swaps.
+func (p *Paths) BinaryPath() string {
+	return filepath.Join(p.CurrentLink(), BinaryName())
+}
+
+// StateFile records what version is installed and where its binary lives.
+func (p *Paths) StateFile() string { return filepath.Join(p.data, "state.json") }

internal/sec/paths_test.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestDefaultPaths_OverrideViaEnv(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv(envInstallDirOverride, dir)
+	p, err := DefaultPaths()
+	if err != nil {
+		t.Fatalf("DefaultPaths: %v", err)
+	}
+	if p.InstallDir() != dir {
+		t.Errorf("InstallDir = %q, want %q", p.InstallDir(), dir)
+	}
+	if p.DataDir() != filepath.Join(dir, "data") {
+		t.Errorf("DataDir = %q, want %s/data", p.DataDir(), dir)
+	}
+	if !strings.HasPrefix(p.StateFile(), dir) {
+		t.Errorf("StateFile not under override root: %q", p.StateFile())
+	}
+}
+
+func TestPaths_Ensure(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv(envInstallDirOverride, dir)
+	p, err := DefaultPaths()
+	if err != nil {
+		t.Fatalf("DefaultPaths: %v", err)
+	}
+	if err := p.Ensure(); err != nil {
+		t.Fatalf("Ensure: %v", err)
+	}
+	for _, d := range []string{p.InstallDir(), p.DataDir(), p.VersionsDir()} {
+		info, err := os.Stat(d)
+		if err != nil {
+			t.Errorf("missing %s: %v", d, err)
+			continue
+		}
+		if !info.IsDir() {
+			t.Errorf("%s is not a directory", d)
+		}
+	}
+}

internal/sec/remote_manifest.go

@@ -0,0 +1,113 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"regexp"
+
+	larkcore "github.com/larksuite/oapi-sdk-go/v3/core"
+
+	"github.com/larksuite/cli/internal/client"
+	"github.com/larksuite/cli/internal/core"
+)
+
+// secCliManifestPath is the OAPI endpoint that returns the per-platform
+// download URLs for lark-sec-cli, gated by tenant_access_token.
+const secCliManifestPath = "/open-apis/security_plugin/v1/sec_cli/manifest"
+
+// xTTEnvEnv, when set, injects an x-tt-env header on the manifest request.
+// Used for BOE / sub-environment routing (e.g. value "boe_tns_api"). Unset
+// in prod — the gateway treats absence as "no override". This is the only
+// debug-routing knob in this file; brand/domain switching itself is handled
+// at the network layer via the lark-env.sh Whistle pattern in the
+// lark-cli maintainer doc.
+const xTTEnvEnv = "LARKSUITE_CLI_X_TT_ENV"
+
+// RemoteManifest is the payload returned by GET /open-apis/security_plugin/v1/sec_cli/manifest
+// for a single (region, platform, arch) combination. The server returns only
+// the download URLs; version metadata is parsed from the URL itself (see
+// versionFromURL).
+type RemoteManifest struct {
+	URLs []string `json:"urls"`
+}
+
+// FetchRemoteManifest calls the OAPI manifest endpoint with TAT (bot) auth
+// and returns the typed payload for the given region/platform/arch. When the
+// LARKSUITE_CLI_X_TT_ENV env var is set, its value is sent as an x-tt-env
+// request header for sub-environment routing.
+//
+// Errors are returned as-is — there is no fallback to the embedded
+// bootstrap manifest. Callers that need offline behavior must handle that
+// explicitly.
+func FetchRemoteManifest(
+	ctx context.Context,
+	ac *client.APIClient,
+	region, platform, arch string,
+	verbose io.Writer,
+) (*RemoteManifest, error) {
+	req := &larkcore.ApiReq{
+		HttpMethod: "GET",
+		ApiPath:    secCliManifestPath,
+		QueryParams: larkcore.QueryParams{
+			"region":   []string{region},
+			"platform": []string{platform},
+			"arch":     []string{arch},
+		},
+	}
+	tracef(verbose, "GET %s?region=%s&platform=%s&arch=%s as=bot", secCliManifestPath, region, platform, arch)
+
+	var extraOpts []larkcore.RequestOptionFunc
+	if v := os.Getenv(xTTEnvEnv); v != "" {
+		h := http.Header{}
+		h.Set("x-tt-env", v)
+		extraOpts = append(extraOpts, larkcore.WithHeaders(h))
+		tracef(verbose, "injecting header x-tt-env=%s (from %s)", v, xTTEnvEnv)
+	}
+
+	resp, err := ac.DoSDKRequest(ctx, req, core.AsBot, extraOpts...)
+	if err != nil {
+		return nil, fmt.Errorf("sec_cli manifest request: %w", err)
+	}
+	tracef(verbose, "response status=%d body-len=%d body=%q", resp.StatusCode, len(resp.RawBody), string(resp.RawBody))
+
+	var env struct {
+		Code int             `json:"code"`
+		Msg  string          `json:"msg"`
+		Data *RemoteManifest `json:"data"`
+	}
+	if err := json.Unmarshal(resp.RawBody, &env); err != nil {
+		// Print body unconditionally on decode failure — a malformed response is
+		// the most common case where the caller needs to see exactly what arrived.
+		fmt.Fprintf(os.Stderr, "[sec_cli manifest] decode failed; status=%d len=%d body=%q\n", resp.StatusCode, len(resp.RawBody), string(resp.RawBody))
+		return nil, fmt.Errorf("sec_cli manifest decode: %w", err)
+	}
+	if env.Code != 0 {
+		return nil, fmt.Errorf("sec_cli manifest error %d: %s", env.Code, env.Msg)
+	}
+	if env.Data == nil || len(env.Data.URLs) == 0 {
+		return nil, fmt.Errorf("sec_cli manifest: no urls for region=%s platform=%s arch=%s", region, platform, arch)
+	}
+	return env.Data, nil
+}
+
+// versionFromURL extracts the release version from a download URL of the form
+//   .../releases/<version>/<pipeline-id>/<platform-arch>/<archive>.zip
+// The server-side manifest does not return version as a discrete field;
+// state.json's Version needs *something* to disambiguate concurrent installs
+// in versions/<version>/, so we parse it out here.
+var releaseVersionRE = regexp.MustCompile(`/releases/([^/]+)/`)
+
+func versionFromURL(u string) (string, error) {
+	m := releaseVersionRE.FindStringSubmatch(u)
+	if len(m) < 2 || m[1] == "" {
+		return "", fmt.Errorf("could not parse release version from URL %q", u)
+	}
+	return m[1], nil
+}

internal/sec/state.go

@@ -0,0 +1,79 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"time"
+)
+
+// State is the JSON document at <data>/state.json describing the currently
+// installed lark-sec-cli artifact. It is the source of truth for what binary
+// to launch. After bootstrap install lark-sec-cli may upgrade itself in
+// place — when that happens this state file is informational only; the
+// daemon owns its own canonical version state.
+type State struct {
+	Version     string    `json:"version"`
+	BuildID     string    `json:"build_id"`
+	InstalledAt time.Time `json:"installed_at"`
+	BinaryPath  string    `json:"binary_path"`
+}
+
+// LoadState reads state.json. Returns (nil, nil) when the file is absent —
+// callers treat that as "not yet installed". Decode errors are surfaced
+// so a corrupt file is never silently overwritten.
+func LoadState(path string) (*State, error) {
+	data, err := os.ReadFile(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	var s State
+	if err := json.Unmarshal(data, &s); err != nil {
+		return nil, fmt.Errorf("parse %s: %w", path, err)
+	}
+	return &s, nil
+}
+
+// SaveState writes state.json atomically: a tmpfile next to the target is
+// fsynced then renamed in, so concurrent readers either see the previous
+// state or the new one — never a torn write.
+func SaveState(path string, s *State) error {
+	data, err := json.MarshalIndent(s, "", "  ")
+	if err != nil {
+		return err
+	}
+	tmp, err := os.CreateTemp(dirOf(path), ".state-*.json")
+	if err != nil {
+		return err
+	}
+	tmpName := tmp.Name()
+	defer os.Remove(tmpName) // no-op after a successful Rename
+	if _, err := tmp.Write(data); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := tmp.Sync(); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+	return os.Rename(tmpName, path)
+}
+
+func dirOf(path string) string {
+	for i := len(path) - 1; i >= 0; i-- {
+		if path[i] == '/' || path[i] == '\\' {
+			return path[:i]
+		}
+	}
+	return "."
+}

internal/sec/state_test.go

@@ -0,0 +1,48 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package sec
+
+import (
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestSaveLoadState_Roundtrip(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "state.json")
+
+	in := &State{
+		Version:     "1.2.3",
+		BuildID:     "build-42",
+		InstalledAt: time.Date(2026, 5, 18, 12, 0, 0, 0, time.UTC),
+		BinaryPath:  "/tmp/lark-sec-cli",
+	}
+	if err := SaveState(path, in); err != nil {
+		t.Fatalf("SaveState: %v", err)
+	}
+	got, err := LoadState(path)
+	if err != nil {
+		t.Fatalf("LoadState: %v", err)
+	}
+	if got == nil {
+		t.Fatal("LoadState returned nil")
+	}
+	if got.Version != in.Version || got.BuildID != in.BuildID || got.BinaryPath != in.BinaryPath {
+		t.Errorf("roundtrip mismatch: got=%+v want=%+v", got, in)
+	}
+	if !got.InstalledAt.Equal(in.InstalledAt) {
+		t.Errorf("InstalledAt mismatch: got=%v want=%v", got.InstalledAt, in.InstalledAt)
+	}
+}
+
+func TestLoadState_AbsentFile(t *testing.T) {
+	got, err := LoadState(filepath.Join(t.TempDir(), "missing.json"))
+	if err != nil {
+		t.Fatalf("expected nil error for missing file, got %v", err)
+	}
+	if got != nil {
+		t.Errorf("expected nil state for missing file, got %+v", got)
+	}
+}

internal/secplugin/README.md

@@ -0,0 +1,135 @@
+# secplugin Usage Guide
+
+Chinese version: see `README.zh-CN.md`.
+
+`secplugin` enables a secure proxy mode for the CLI. It forces outbound HTTP(S)
+requests to go through a local security proxy and can optionally trust an
+additional CA certificate bundle.
+
+It supports two configuration methods:
+
+1. `sec_config.json`
+2. `LARKSUITE_CLI_SEC_*` environment variables
+
+## Config File Location
+
+Default config file path:
+
+```text
+~/.lark-cli/sec_config.json
+```
+
+If `LARKSUITE_CLI_CONFIG_DIR` is set, the path becomes:
+
+```text
+$LARKSUITE_CLI_CONFIG_DIR/sec_config.json
+```
+
+## Option 1: Config File
+
+Put the following content into `sec_config.json`:
+
+```json
+{
+  "LARKSUITE_CLI_SEC_ENABLE": true,
+  "LARKSUITE_CLI_SEC_PROXY": "http://127.0.0.1:3128",
+  "LARKSUITE_CLI_SEC_CA": "/absolute/path/to/proxy-ca.pem",
+  "LARKSUITE_CLI_SEC_AUTH": true,
+  "LARKSUITE_CLI_APP_ID": "cli_xxx",
+  "LARKSUITE_CLI_BRAND": "feishu",
+  "LARKSUITE_CLI_DEFAULT_AS": "bot",
+  "LARKSUITE_CLI_STRICT_MODE": "bot"
+}
+```
+
+Field descriptions:
+
+- `LARKSUITE_CLI_SEC_ENABLE`: Enables secplugin. Boolean values are supported.
+- `LARKSUITE_CLI_SEC_PROXY`: Local HTTP proxy address. It must be `http://127.0.0.1:<port>`.
+- `LARKSUITE_CLI_SEC_CA`: Absolute path to an extra trusted root CA PEM file. Leave empty if not needed.
+- `LARKSUITE_CLI_SEC_AUTH`: Enables proxy-injected token mode.
+- `LARKSUITE_CLI_APP_ID`: Optional app ID used in `SEC_AUTH` mode.
+- `LARKSUITE_CLI_BRAND`: Optional, must be `feishu` or `lark`.
+- `LARKSUITE_CLI_DEFAULT_AS`: Optional, must be `user`, `bot`, or `auto`.
+- `LARKSUITE_CLI_STRICT_MODE`: Optional, must be `user`, `bot`, or `off`.
+
+## Option 2: Environment Variables
+
+You can also enable secplugin directly with environment variables without
+creating `sec_config.json`:
+
+```bash
+export LARKSUITE_CLI_SEC_ENABLE=true
+export LARKSUITE_CLI_SEC_PROXY=http://127.0.0.1:3128
+export LARKSUITE_CLI_SEC_CA=/absolute/path/to/proxy-ca.pem
+export LARKSUITE_CLI_SEC_AUTH=true
+```
+
+If you want to provide app metadata in `SEC_AUTH` mode, set these as well:
+
+```bash
+export LARKSUITE_CLI_APP_ID=cli_xxx
+export LARKSUITE_CLI_BRAND=feishu
+export LARKSUITE_CLI_DEFAULT_AS=bot
+export LARKSUITE_CLI_STRICT_MODE=bot
+```
+
+## Precedence
+
+The following environment variables override the corresponding fields in
+`sec_config.json` when they are present:
+
+- `LARKSUITE_CLI_SEC_ENABLE`
+- `LARKSUITE_CLI_SEC_PROXY`
+- `LARKSUITE_CLI_SEC_CA`
+- `LARKSUITE_CLI_SEC_AUTH`
+- `LARKSUITE_CLI_APP_ID`
+- `LARKSUITE_CLI_BRAND`
+- `LARKSUITE_CLI_DEFAULT_AS`
+- `LARKSUITE_CLI_STRICT_MODE`
+
+This means:
+
+- Put stable defaults in `sec_config.json`.
+- Use environment variables for temporary overrides.
+- SEC-related environment variables can work even without a config file.
+
+## SEC_AUTH Mode
+
+The CLI enters `SEC_AUTH` mode when both of the following are true:
+
+```text
+LARKSUITE_CLI_SEC_ENABLE=true
+LARKSUITE_CLI_SEC_AUTH=true
+```
+
+In this mode, the CLI does not read real tokens directly. Instead, it returns
+placeholder tokens and expects the proxy to replace them with real credentials.
+
+App information is resolved in this order:
+
+1. `LARKSUITE_CLI_APP_ID` and `LARKSUITE_CLI_BRAND` from environment variables
+2. The same fields in `sec_config.json`
+3. The active profile in the regular CLI `config.json`
+
+If no valid app information can be resolved from any source, the command fails.
+
+## Constraints
+
+- `LARKSUITE_CLI_SEC_PROXY` must use the `http` scheme only.
+- The host of `LARKSUITE_CLI_SEC_PROXY` must be `127.0.0.1`.
+- `LARKSUITE_CLI_SEC_PROXY` must not contain a path.
+- `LARKSUITE_CLI_SEC_CA` must be an absolute path to a PEM file.
+- Boolean values support `true/false`, `1/0`, `on/off`, `yes/no`, and `y/n`.
+
+## Recommendations
+
+For long-term stable setup, prefer `sec_config.json`:
+
+- Good for developer machines or controlled environments.
+- Avoids repeatedly injecting environment variables into the shell.
+
+For temporary debugging, prefer environment variables:
+
+- Good for switching proxy or CA for just one session.
+- No need to modify files on disk.

internal/secplugin/README.zh-CN.md

@@ -0,0 +1,130 @@
+# secplugin 使用说明
+
+English version: see `README.md`.
+
+`secplugin` 用于开启安全代理模式，让 CLI 的 HTTP(S) 请求固定走本地安全代理，并按需信任额外 CA 证书。
+
+支持两种配置方式：
+
+1. `sec_config.json`
+2. `LARKSUITE_CLI_SEC_*` 环境变量
+
+## 配置文件位置
+
+默认配置文件路径：
+
+```text
+~/.lark-cli/sec_config.json
+```
+
+如果设置了 `LARKSUITE_CLI_CONFIG_DIR`，则配置文件路径变为：
+
+```text
+$LARKSUITE_CLI_CONFIG_DIR/sec_config.json
+```
+
+## 方式一：使用配置文件
+
+在 `sec_config.json` 中写入：
+
+```json
+{
+  "LARKSUITE_CLI_SEC_ENABLE": true,
+  "LARKSUITE_CLI_SEC_PROXY": "http://127.0.0.1:3128",
+  "LARKSUITE_CLI_SEC_CA": "/absolute/path/to/proxy-ca.pem",
+  "LARKSUITE_CLI_SEC_AUTH": true,
+  "LARKSUITE_CLI_APP_ID": "cli_xxx",
+  "LARKSUITE_CLI_BRAND": "feishu",
+  "LARKSUITE_CLI_DEFAULT_AS": "bot",
+  "LARKSUITE_CLI_STRICT_MODE": "bot"
+}
+```
+
+字段说明：
+
+- `LARKSUITE_CLI_SEC_ENABLE`: 是否启用 secplugin，支持布尔值。
+- `LARKSUITE_CLI_SEC_PROXY`: 本地 HTTP 代理地址，必须是 `http://127.0.0.1:<port>`。
+- `LARKSUITE_CLI_SEC_CA`: 额外信任的根证书 PEM 文件绝对路径；不需要时可留空。
+- `LARKSUITE_CLI_SEC_AUTH`: 是否启用代理注入 token 模式。
+- `LARKSUITE_CLI_APP_ID`: 可选，`SEC_AUTH` 模式下使用的应用 ID。
+- `LARKSUITE_CLI_BRAND`: 可选，取值为 `feishu` 或 `lark`。
+- `LARKSUITE_CLI_DEFAULT_AS`: 可选，取值为 `user`、`bot` 或 `auto`。
+- `LARKSUITE_CLI_STRICT_MODE`: 可选，取值为 `user`、`bot` 或 `off`。
+
+## 方式二：使用环境变量
+
+也可以不写 `sec_config.json`，直接通过环境变量启用：
+
+```bash
+export LARKSUITE_CLI_SEC_ENABLE=true
+export LARKSUITE_CLI_SEC_PROXY=http://127.0.0.1:3128
+export LARKSUITE_CLI_SEC_CA=/absolute/path/to/proxy-ca.pem
+export LARKSUITE_CLI_SEC_AUTH=true
+```
+
+如果你在 `SEC_AUTH` 模式下希望同时提供应用信息，也可以继续设置：
+
+```bash
+export LARKSUITE_CLI_APP_ID=cli_xxx
+export LARKSUITE_CLI_BRAND=feishu
+export LARKSUITE_CLI_DEFAULT_AS=bot
+export LARKSUITE_CLI_STRICT_MODE=bot
+```
+
+## 配置优先级
+
+以下环境变量存在时，会覆盖 `sec_config.json` 中对应字段：
+
+- `LARKSUITE_CLI_SEC_ENABLE`
+- `LARKSUITE_CLI_SEC_PROXY`
+- `LARKSUITE_CLI_SEC_CA`
+- `LARKSUITE_CLI_SEC_AUTH`
+- `LARKSUITE_CLI_APP_ID`
+- `LARKSUITE_CLI_BRAND`
+- `LARKSUITE_CLI_DEFAULT_AS`
+- `LARKSUITE_CLI_STRICT_MODE`
+
+也就是说：
+
+- 你可以把默认值写进 `sec_config.json`。
+- 再用环境变量做临时覆盖。
+- 如果没有配置文件，但设置了 SEC 相关环境变量，也可以正常工作。
+
+## SEC_AUTH 模式说明
+
+当同时满足以下条件时，CLI 会进入 `SEC_AUTH` 模式：
+
+```text
+LARKSUITE_CLI_SEC_ENABLE=true
+LARKSUITE_CLI_SEC_AUTH=true
+```
+
+此时 CLI 不直接读取真实 token，而是返回占位 token，由代理替换成真实凭证。
+
+应用信息来源优先级如下：
+
+1. 环境变量中的 `LARKSUITE_CLI_APP_ID` 和 `LARKSUITE_CLI_BRAND`
+2. `sec_config.json` 中的同名字段
+3. 常规 CLI 配置文件 `config.json` 的当前 profile
+
+如果以上来源都拿不到可用应用信息，命令会报错。
+
+## 参数约束
+
+- `LARKSUITE_CLI_SEC_PROXY` 只允许 `http` 协议。
+- `LARKSUITE_CLI_SEC_PROXY` 的 host 必须是 `127.0.0.1`。
+- `LARKSUITE_CLI_SEC_PROXY` 不能带路径。
+- `LARKSUITE_CLI_SEC_CA` 必须是 PEM 文件的绝对路径。
+- 布尔值支持 `true/false`、`1/0`、`on/off`、`yes/no`、`y/n`。
+
+## 推荐用法
+
+长期固定配置建议使用 `sec_config.json`：
+
+- 适合开发机或受控环境的稳定配置。
+- 避免在 shell 中反复注入环境变量。
+
+临时调试建议使用环境变量：
+
+- 适合本次会话临时切换代理或证书。
+- 不需要修改磁盘上的配置文件。

internal/secplugin/config.go

@@ -0,0 +1,277 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+// Package secplugin implements the ~/.lark-cli/sec_config.json based security proxy plugin mode.
+//
+// It supports:
+// - forcing all outbound HTTP(S) requests through a fixed HTTP proxy
+// - trusting an additional root CA PEM bundle for MITM/inspection proxies
+// - optional "proxy injects token" mode via placeholder tokens (SEC_AUTH)
+//
+// In sec plugin mode, certain common CLI env vars (APP_ID / BRAND / DEFAULT_AS /
+// STRICT_MODE) can also be set in sec_config.json so sandboxes can avoid
+// environment injection. When both are present, environment variables win.
+package secplugin
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/larksuite/cli/internal/core"
+	"github.com/larksuite/cli/internal/envvars"
+	"github.com/larksuite/cli/internal/vfs"
+)
+
+// SEC plugin constants cover the config file name and placeholder token values.
+const (
+	// ConfigFileName is the fixed config file name under core.GetConfigDir().
+	ConfigFileName = "sec_config.json"
+
+	// SentinelUAT is the placeholder user access token used in SEC_AUTH mode.
+	SentinelUAT = "secplugin-managed-uat"
+
+	// SentinelTAT is the placeholder tenant access token used in SEC_AUTH mode.
+	SentinelTAT = "secplugin-managed-tat"
+)
+
+// Config is the on-disk config format. Keys intentionally mirror env var names.
+type Config struct {
+	// Enable turns on sec plugin transport handling.
+	Enable bool `json:"LARKSUITE_CLI_SEC_ENABLE"`
+
+	// Proxy is the fixed HTTP proxy address used for all outbound requests.
+	Proxy string `json:"LARKSUITE_CLI_SEC_PROXY"`
+
+	// CAPath points to an extra PEM bundle trusted for proxy TLS interception.
+	CAPath string `json:"LARKSUITE_CLI_SEC_CA"`
+
+	// Auth enables placeholder-token mode for proxy-side credential injection.
+	Auth bool `json:"LARKSUITE_CLI_SEC_AUTH"`
+
+	// Optional defaults for sec plugin mode; env vars override these.
+	// AppID supplies the app ID when the environment does not set one.
+	AppID string `json:"LARKSUITE_CLI_APP_ID,omitempty"`
+
+	// Brand supplies the tenant brand when the environment does not set one.
+	Brand string `json:"LARKSUITE_CLI_BRAND,omitempty"` // feishu | lark
+
+	// DefaultAs supplies the default identity when the environment does not set one.
+	DefaultAs string `json:"LARKSUITE_CLI_DEFAULT_AS,omitempty"` // user | bot | auto
+
+	// StrictMode supplies the strict mode when the environment does not set one.
+	StrictMode string `json:"LARKSUITE_CLI_STRICT_MODE,omitempty"` // user | bot | off
+}
+
+// Path returns the absolute path to the sec plugin config file.
+func Path() string {
+	return filepath.Join(core.GetConfigDir(), ConfigFileName)
+}
+
+// loadOnce guards one-time SEC config loading for process-wide transport reuse.
+var loadOnce sync.Once
+
+// loadCfg stores the cached SEC config after the first successful Load call.
+var loadCfg *Config
+
+// loadErr stores the cached Load error observed during the first load attempt.
+var loadErr error
+
+// Load reads ~/.lark-cli/sec_config.json once and caches the parsed result.
+// Environment variables (CliSec*) take precedence over config file values.
+//
+// Returns (nil, nil) only when:
+//   - the config file does not exist AND
+//   - none of the SEC-related env vars are present.
+func Load() (*Config, error) {
+	loadOnce.Do(func() {
+		// Start from env-only config if any SEC env var is present.
+		cfg, hasEnv, err := loadFromEnv()
+		if err != nil {
+			loadErr = err
+			return
+		}
+
+		p := Path()
+		if _, err := vfs.Stat(p); err != nil {
+			if errors.Is(err, os.ErrNotExist) {
+				// No file: return env-only config (if any), else nil.
+				if hasEnv {
+					loadCfg = cfg
+				} else {
+					loadCfg = nil
+				}
+				loadErr = nil
+				return
+			}
+			loadErr = fmt.Errorf("failed to stat sec plugin config %q: %w", p, err)
+			return
+		}
+		b, err := vfs.ReadFile(p)
+		if err != nil {
+			loadErr = fmt.Errorf("failed to read sec plugin config %q: %w", p, err)
+			return
+		}
+		var fileCfg Config
+		if err := json.Unmarshal(b, &fileCfg); err != nil {
+			loadErr = fmt.Errorf("invalid sec plugin config %q: %w", p, err)
+			return
+		}
+
+		// Merge: file base + env overrides.
+		if cfg == nil {
+			cfg = &fileCfg
+		} else {
+			*cfg = fileCfg
+			applyEnvOverrides(cfg)
+		}
+		loadCfg = cfg
+	})
+	return loadCfg, loadErr
+}
+
+// Enabled reports whether SEC plugin mode is enabled.
+func (c *Config) Enabled() bool { return c != nil && c.Enable }
+
+// AuthEnabled reports whether SEC_AUTH token placeholder mode is enabled.
+func (c *Config) AuthEnabled() bool { return c != nil && c.Enable && c.Auth }
+
+// loadFromEnv builds a config from SEC-related environment variables only.
+// It reports whether any SEC-related environment variable was present.
+func loadFromEnv() (*Config, bool, error) {
+	_, hasEnable := os.LookupEnv(envvars.CliSecEnable)
+	_, hasProxy := os.LookupEnv(envvars.CliSecProxy)
+	_, hasCA := os.LookupEnv(envvars.CliSecCA)
+	_, hasAuth := os.LookupEnv(envvars.CliSecAuth)
+	hasAny := hasEnable || hasProxy || hasCA || hasAuth
+	if !hasAny {
+		return nil, false, nil
+	}
+	cfg := &Config{}
+	if err := applyEnvOverrides(cfg); err != nil {
+		return nil, true, err
+	}
+	return cfg, true, nil
+}
+
+// applyEnvOverrides copies SEC-related environment variable values into cfg.
+func applyEnvOverrides(cfg *Config) error {
+	if v, ok := os.LookupEnv(envvars.CliSecEnable); ok {
+		b, err := parseBoolEnv(envvars.CliSecEnable, v)
+		if err != nil {
+			return err
+		}
+		cfg.Enable = b
+	}
+	if v, ok := os.LookupEnv(envvars.CliSecAuth); ok {
+		b, err := parseBoolEnv(envvars.CliSecAuth, v)
+		if err != nil {
+			return err
+		}
+		cfg.Auth = b
+	}
+	if v, ok := os.LookupEnv(envvars.CliSecProxy); ok {
+		cfg.Proxy = v
+	}
+	if v, ok := os.LookupEnv(envvars.CliSecCA); ok {
+		cfg.CAPath = v
+	}
+	return nil
+}
+
+// parseBoolEnv accepts common boolean spellings used in environment variables.
+func parseBoolEnv(name, raw string) (bool, error) {
+	s := strings.TrimSpace(strings.ToLower(raw))
+	if s == "" {
+		// Treat empty as false when explicitly present.
+		return false, nil
+	}
+	switch s {
+	case "1", "true", "on", "yes", "y":
+		return true, nil
+	case "0", "false", "off", "no", "n":
+		return false, nil
+	}
+	if b, err := strconv.ParseBool(s); err == nil {
+		return b, nil
+	}
+	return false, fmt.Errorf("invalid %s %q (want true/false/1/0)", name, raw)
+}
+
+// proxyURL validates the fixed SEC proxy configuration and returns its URL.
+func (c *Config) proxyURL() (*url.URL, error) {
+	raw := strings.TrimSpace(c.Proxy)
+	if raw == "" {
+		return nil, fmt.Errorf("%s is empty", envvars.CliSecProxy)
+	}
+	redacted := redactProxyURL(raw)
+	u, err := url.Parse(raw)
+	if err != nil {
+		return nil, fmt.Errorf("invalid %s %q: %w", envvars.CliSecProxy, redacted, err)
+	}
+	if u.Scheme != "http" {
+		return nil, fmt.Errorf("invalid %s %q: scheme must be http", envvars.CliSecProxy, redacted)
+	}
+	if u.Host == "" {
+		return nil, fmt.Errorf("invalid %s %q: missing host", envvars.CliSecProxy, redacted)
+	}
+	// Security hardening: only allow a loopback proxy. This prevents accidental
+	// cross-machine proxying of credentials/traffic.
+	if u.Hostname() != "127.0.0.1" {
+		return nil, fmt.Errorf("invalid %s %q: host must be 127.0.0.1", envvars.CliSecProxy, redacted)
+	}
+	if u.Port() == "" {
+		return nil, fmt.Errorf("invalid %s %q: explicit port is required", envvars.CliSecProxy, redacted)
+	}
+	if u.Path != "" && u.Path != "/" {
+		return nil, fmt.Errorf("invalid %s %q: path is not allowed", envvars.CliSecProxy, redacted)
+	}
+	if u.RawQuery != "" {
+		return nil, fmt.Errorf("invalid %s %q: query is not allowed", envvars.CliSecProxy, redacted)
+	}
+	if u.Fragment != "" {
+		return nil, fmt.Errorf("invalid %s %q: fragment is not allowed", envvars.CliSecProxy, redacted)
+	}
+	return u, nil
+}
+
+// redactProxyURL masks userinfo (username:password) in a proxy URL.
+// Handles both scheme-prefixed ("http://user:pass@host") and bare formats.
+func redactProxyURL(raw string) string {
+	u, err := url.Parse(raw)
+	if err == nil && u.User != nil {
+		u.User = url.User("***")
+		return u.String()
+	}
+	// Fallback: handle "user:pass@proxy:8080"
+	if at := strings.LastIndex(raw, "@"); at > 0 {
+		return "***@" + raw[at+1:]
+	}
+	return raw
+}
+
+// ApplyToTransport clones base and applies SEC plugin settings to the clone.
+// Caller owns the returned *http.Transport.
+func (c *Config) ApplyToTransport(base *http.Transport) (*http.Transport, error) {
+	if base == nil {
+		base = http.DefaultTransport.(*http.Transport)
+	}
+	u, err := c.proxyURL()
+	if err != nil {
+		return nil, err
+	}
+
+	t := base.Clone()
+	t.Proxy = http.ProxyURL(u) // fixed proxy overrides environment proxy vars
+	if err := applyExtraRootCA(t, c.CAPath); err != nil {
+		return nil, err
+	}
+	return t, nil
+}

internal/secplugin/config_test.go

@@ -0,0 +1,245 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package secplugin
+
+import (
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+
+	"github.com/larksuite/cli/internal/envvars"
+)
+
+// unsetEnv clears key for the duration of the test and restores its original value.
+func unsetEnv(t *testing.T, key string) {
+	t.Helper()
+	old, had := os.LookupEnv(key)
+	_ = os.Unsetenv(key)
+	t.Cleanup(func() {
+		if had {
+			_ = os.Setenv(key, old)
+		} else {
+			_ = os.Unsetenv(key)
+		}
+	})
+}
+
+// unsetSecPluginEnv clears SEC-related environment variables for deterministic tests.
+func unsetSecPluginEnv(t *testing.T) {
+	t.Helper()
+	unsetEnv(t, envvars.CliSecEnable)
+	unsetEnv(t, envvars.CliSecProxy)
+	unsetEnv(t, envvars.CliSecCA)
+	unsetEnv(t, envvars.CliSecAuth)
+}
+
+// writeFile creates parent directories and writes test data for fixtures.
+func writeFile(t *testing.T, path string, data []byte, perm os.FileMode) {
+	t.Helper()
+	if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil {
+		t.Fatalf("MkdirAll: %v", err)
+	}
+	if err := os.WriteFile(path, data, perm); err != nil {
+		t.Fatalf("WriteFile: %v", err)
+	}
+}
+
+// TestLoad_MissingFileReturnsNil verifies that Load reports no config when no file
+// or SEC environment overrides exist.
+func TestLoad_MissingFileReturnsNil(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	loadOnce = sync.Once{}
+	loadCfg = nil
+	loadErr = nil
+	unsetSecPluginEnv(t)
+	// TestLoad_MissingFileReturnsNil must reset loadOnce, loadCfg, and loadErr
+	// because multiple tests in this package share the package-level Load()
+	// cache via sync.Once.
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg != nil {
+		t.Fatalf("Load() = %#v, want nil (missing file)", cfg)
+	}
+}
+
+// TestApplyToTransport_SetsProxy verifies that a valid SEC config installs a fixed proxy.
+func TestApplyToTransport_SetsProxy(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	loadOnce = sync.Once{}
+	loadCfg = nil
+	loadErr = nil
+	unsetSecPluginEnv(t)
+
+	cfgPath := Path()
+	writeFile(t, cfgPath, []byte(`{
+  "LARKSUITE_CLI_SEC_ENABLE": true,
+  "LARKSUITE_CLI_SEC_PROXY": "http://127.0.0.1:3128",
+  "LARKSUITE_CLI_SEC_CA": "",
+  "LARKSUITE_CLI_SEC_AUTH": false
+}`), 0600)
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg == nil || !cfg.Enabled() {
+		t.Fatalf("cfg.Enabled() = %v, want true", cfg)
+	}
+
+	base := http.DefaultTransport.(*http.Transport)
+	tr, err := cfg.ApplyToTransport(base)
+	if err != nil {
+		t.Fatalf("ApplyToTransport() error = %v", err)
+	}
+	if tr.Proxy == nil {
+		t.Fatal("Proxy func is nil, want fixed proxy")
+	}
+	u, err := tr.Proxy(&http.Request{URL: &url.URL{Scheme: "https", Host: "open.feishu.cn"}})
+	if err != nil {
+		t.Fatalf("Proxy() error = %v", err)
+	}
+	if u == nil || u.String() != "http://127.0.0.1:3128" {
+		t.Fatalf("Proxy() = %v, want http://127.0.0.1:3128", u)
+	}
+}
+
+// TestLoad_RejectsNonLoopbackProxy verifies that SEC mode rejects non-loopback proxies.
+func TestLoad_RejectsNonLoopbackProxy(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	loadOnce = sync.Once{}
+	loadCfg = nil
+	loadErr = nil
+	unsetSecPluginEnv(t)
+
+	cfgPath := Path()
+	writeFile(t, cfgPath, []byte(`{
+  "LARKSUITE_CLI_SEC_ENABLE": true,
+  "LARKSUITE_CLI_SEC_PROXY": "http://10.0.0.1:3128",
+  "LARKSUITE_CLI_SEC_CA": "",
+  "LARKSUITE_CLI_SEC_AUTH": false
+}`), 0600)
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg == nil || !cfg.Enabled() {
+		t.Fatalf("cfg.Enabled() = %v, want true", cfg)
+	}
+	_, err = cfg.ApplyToTransport(http.DefaultTransport.(*http.Transport))
+	if err == nil {
+		t.Fatal("ApplyToTransport() error = nil, want invalid proxy host error")
+	}
+}
+
+// TestConfig_ProxyURLRejectsUnsupportedParts verifies the SEC proxy validator
+// rejects URLs with missing ports, queries, and fragments.
+func TestConfig_ProxyURLRejectsUnsupportedParts(t *testing.T) {
+	cases := []struct {
+		name string
+		raw  string
+		want string
+	}{
+		{
+			name: "missing explicit port",
+			raw:  "http://127.0.0.1",
+			want: "explicit port is required",
+		},
+		{
+			name: "query string",
+			raw:  "http://127.0.0.1:3128?foo=bar",
+			want: "query is not allowed",
+		},
+		{
+			name: "fragment",
+			raw:  "http://127.0.0.1:3128#frag",
+			want: "fragment is not allowed",
+		},
+	}
+
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := (&Config{Proxy: tt.raw}).proxyURL()
+			if err == nil {
+				t.Fatalf("proxyURL() error = nil, want substring %q", tt.want)
+			}
+			if !strings.Contains(err.Error(), tt.want) {
+				t.Fatalf("proxyURL() error = %q, want substring %q", err, tt.want)
+			}
+		})
+	}
+}
+
+// TestLoad_EnvOnlyConfig verifies that SEC settings can come entirely from environment variables.
+func TestLoad_EnvOnlyConfig(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	loadOnce = sync.Once{}
+	loadCfg = nil
+	loadErr = nil
+
+	t.Setenv(envvars.CliSecEnable, "true")
+	t.Setenv(envvars.CliSecProxy, "http://127.0.0.1:7777")
+	t.Setenv(envvars.CliSecCA, "")
+	t.Setenv(envvars.CliSecAuth, "true")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg == nil || !cfg.Enabled() {
+		t.Fatalf("cfg.Enabled() = %v, want true", cfg)
+	}
+	if !cfg.AuthEnabled() {
+		t.Fatalf("cfg.AuthEnabled() = false, want true")
+	}
+	tr, err := cfg.ApplyToTransport(http.DefaultTransport.(*http.Transport))
+	if err != nil {
+		t.Fatalf("ApplyToTransport() error = %v", err)
+	}
+	u, err := tr.Proxy(&http.Request{URL: &url.URL{Scheme: "https", Host: "open.feishu.cn"}})
+	if err != nil {
+		t.Fatalf("Proxy() error = %v", err)
+	}
+	if u == nil || u.String() != "http://127.0.0.1:7777" {
+		t.Fatalf("Proxy() = %v, want http://127.0.0.1:7777", u)
+	}
+}
+
+// TestLoad_EnvOverridesFile verifies that SEC environment variables override file values.
+func TestLoad_EnvOverridesFile(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	loadOnce = sync.Once{}
+	loadCfg = nil
+	loadErr = nil
+
+	// File enables with one proxy.
+	cfgPath := Path()
+	writeFile(t, cfgPath, []byte(`{
+  "LARKSUITE_CLI_SEC_ENABLE": true,
+  "LARKSUITE_CLI_SEC_PROXY": "http://127.0.0.1:3128",
+  "LARKSUITE_CLI_SEC_CA": "",
+  "LARKSUITE_CLI_SEC_AUTH": false
+}`), 0600)
+
+	// Env overrides: disable + different proxy (should be irrelevant once disabled).
+	t.Setenv(envvars.CliSecEnable, "false")
+	t.Setenv(envvars.CliSecProxy, "http://127.0.0.1:9999")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("Load() error = %v", err)
+	}
+	if cfg == nil {
+		t.Fatalf("Load() = nil, want non-nil (file exists)")
+	}
+	if cfg.Enabled() {
+		t.Fatalf("cfg.Enabled() = true, want false (env override)")
+	}
+}

internal/secplugin/tls_ca.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package secplugin
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"net/http"
+	"path/filepath"
+	"strings"
+
+	"github.com/larksuite/cli/internal/envvars"
+	"github.com/larksuite/cli/internal/vfs"
+)
+
+// applyExtraRootCA augments t with an additional PEM bundle used for SEC proxy
+// TLS interception.
+func applyExtraRootCA(t *http.Transport, caPath string) error {
+	caPath = strings.TrimSpace(caPath)
+	if caPath == "" {
+		return nil
+	}
+	if !filepath.IsAbs(caPath) {
+		return fmt.Errorf("invalid %s %q: must be an absolute path to a PEM file", envvars.CliSecCA, caPath)
+	}
+	pemBytes, err := vfs.ReadFile(caPath)
+	if err != nil {
+		return fmt.Errorf("failed to read %s %q: %w", envvars.CliSecCA, caPath, err)
+	}
+
+	// Start from system pool when possible; if unavailable, create a new pool.
+	pool, _ := x509.SystemCertPool()
+	if pool == nil {
+		pool = x509.NewCertPool()
+	}
+	if ok := pool.AppendCertsFromPEM(pemBytes); !ok {
+		return fmt.Errorf("invalid %s %q: no certificates parsed from PEM", envvars.CliSecCA, caPath)
+	}
+
+	if t.TLSClientConfig == nil {
+		t.TLSClientConfig = &tls.Config{}
+	} else {
+		// Clone to avoid mutating shared config from the base transport.
+		t.TLSClientConfig = t.TLSClientConfig.Clone()
+	}
+	t.TLSClientConfig.MinVersion = tls.VersionTLS12
+	t.TLSClientConfig.RootCAs = pool
+	return nil
+}

internal/secplugin/tls_ca_test.go

@@ -0,0 +1,138 @@
+// Copyright (c) 2026 Lark Technologies Pte. Ltd.
+// SPDX-License-Identifier: MIT
+
+package secplugin
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+	"net/http"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// mustCreateTestCertPEM generates a short-lived self-signed CA certificate for tests.
+func mustCreateTestCertPEM(t *testing.T) []byte {
+	t.Helper()
+
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		t.Fatalf("GenerateKey() error = %v", err)
+	}
+
+	der, err := x509.CreateCertificate(rand.Reader, &x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "secplugin-test-ca",
+		},
+		NotBefore:             time.Now().Add(-time.Hour),
+		NotAfter:              time.Now().Add(time.Hour),
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		IsCA:                  true,
+		BasicConstraintsValid: true,
+	}, &x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "secplugin-test-ca",
+		},
+		NotBefore:             time.Now().Add(-time.Hour),
+		NotAfter:              time.Now().Add(time.Hour),
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		IsCA:                  true,
+		BasicConstraintsValid: true,
+	}, &key.PublicKey, key)
+	if err != nil {
+		t.Fatalf("CreateCertificate() error = %v", err)
+	}
+
+	return pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: der})
+}
+
+// TestApplyExtraRootCA_EmptyPathIsNoop verifies that an empty CA path leaves the transport unchanged.
+func TestApplyExtraRootCA_EmptyPathIsNoop(t *testing.T) {
+	tr := &http.Transport{}
+
+	if err := applyExtraRootCA(tr, "   "); err != nil {
+		t.Fatalf("applyExtraRootCA() error = %v", err)
+	}
+	if tr.TLSClientConfig != nil {
+		t.Fatalf("TLSClientConfig = %#v, want nil", tr.TLSClientConfig)
+	}
+}
+
+// TestApplyExtraRootCA_RejectsRelativePath verifies that CA paths must be absolute.
+func TestApplyExtraRootCA_RejectsRelativePath(t *testing.T) {
+	tr := &http.Transport{}
+
+	err := applyExtraRootCA(tr, "ca.pem")
+	if err == nil || !strings.Contains(err.Error(), "must be an absolute path") {
+		t.Fatalf("applyExtraRootCA() error = %v, want absolute-path error", err)
+	}
+}
+
+// TestApplyExtraRootCA_RejectsMissingFile verifies read errors for missing PEM bundles.
+func TestApplyExtraRootCA_RejectsMissingFile(t *testing.T) {
+	tr := &http.Transport{}
+
+	err := applyExtraRootCA(tr, filepath.Join(t.TempDir(), "missing.pem"))
+	if err == nil || !strings.Contains(err.Error(), "failed to read") {
+		t.Fatalf("applyExtraRootCA() error = %v, want read error", err)
+	}
+}
+
+// TestApplyExtraRootCA_RejectsInvalidPEM verifies validation of malformed PEM bundles.
+func TestApplyExtraRootCA_RejectsInvalidPEM(t *testing.T) {
+	caPath := filepath.Join(t.TempDir(), "invalid.pem")
+	writeFile(t, caPath, []byte("not a pem"), 0600)
+
+	tr := &http.Transport{}
+	err := applyExtraRootCA(tr, caPath)
+	if err == nil || !strings.Contains(err.Error(), "no certificates parsed from PEM") {
+		t.Fatalf("applyExtraRootCA() error = %v, want invalid PEM error", err)
+	}
+}
+
+// TestApplyExtraRootCA_SetsTLSConfigWhenMissing verifies initialization of TLSClientConfig when absent.
+func TestApplyExtraRootCA_SetsTLSConfigWhenMissing(t *testing.T) {
+	caPath := filepath.Join(t.TempDir(), "ca.pem")
+	writeFile(t, caPath, mustCreateTestCertPEM(t), 0600)
+
+	tr := &http.Transport{}
+	if err := applyExtraRootCA(tr, caPath); err != nil {
+		t.Fatalf("applyExtraRootCA() error = %v", err)
+	}
+	if tr.TLSClientConfig == nil {
+		t.Fatal("TLSClientConfig = nil, want initialized config")
+	}
+	if tr.TLSClientConfig.RootCAs == nil {
+		t.Fatal("RootCAs = nil, want cert pool")
+	}
+}
+
+// TestApplyExtraRootCA_ClonesExistingTLSConfig verifies cloning when the base transport already has TLS settings.
+func TestApplyExtraRootCA_ClonesExistingTLSConfig(t *testing.T) {
+	caPath := filepath.Join(t.TempDir(), "ca.pem")
+	writeFile(t, caPath, mustCreateTestCertPEM(t), 0600)
+
+	original := &tls.Config{ServerName: "open.feishu.cn"}
+	tr := &http.Transport{TLSClientConfig: original}
+	if err := applyExtraRootCA(tr, caPath); err != nil {
+		t.Fatalf("applyExtraRootCA() error = %v", err)
+	}
+	if tr.TLSClientConfig == original {
+		t.Fatal("TLSClientConfig pointer reused, want clone")
+	}
+	if tr.TLSClientConfig.ServerName != original.ServerName {
+		t.Fatalf("ServerName = %q, want %q", tr.TLSClientConfig.ServerName, original.ServerName)
+	}
+	if tr.TLSClientConfig.RootCAs == nil {
+		t.Fatal("RootCAs = nil, want cert pool")
+	}
+}

internal/util/proxy.go

@@ -11,8 +11,11 @@ import (
 	"os"
 	"strings"
 	"sync"
+
+	"github.com/larksuite/cli/internal/secplugin"
 )
 
+// Proxy environment constants control shared transport proxy behavior.
 const (
 	// EnvNoProxy disables automatic proxy support when set to any non-empty value.
 	EnvNoProxy = "LARK_CLI_NO_PROXY"
@@ -36,6 +39,7 @@ func DetectProxyEnv() (key, value string) {
 	return "", ""
 }
 
+// proxyWarningOnce ensures proxy environment warnings are emitted at most once.
 var proxyWarningOnce sync.Once
 
 // redactProxyURL masks userinfo (username:password) in a proxy URL.
@@ -84,6 +88,31 @@ var noProxyTransport = sync.OnceValue(func() *http.Transport {
 	return t
 })
 
+// secProxyTransport is a fixed-proxy clone of http.DefaultTransport (with optional
+// custom root CA), lazily built on first use when sec plugin mode is enabled.
+var secProxyTransport = sync.OnceValue(func() *http.Transport {
+	def, ok := http.DefaultTransport.(*http.Transport)
+	if !ok {
+		return &http.Transport{}
+	}
+
+	cfg, err := secplugin.Load()
+	if err != nil || cfg == nil || !cfg.Enabled() {
+		return def
+	}
+	t, err := cfg.ApplyToTransport(def)
+	if err != nil {
+		// Fail closed: do not silently fall back to direct egress when the
+		// operator explicitly enabled SEC plugin mode.
+		blocked := def.Clone()
+		blocked.Proxy = func(*http.Request) (*url.URL, error) {
+			return nil, fmt.Errorf("sec plugin enabled but config is invalid: %v", err)
+		}
+		return blocked
+	}
+	return t
+})
+
 // SharedTransport returns the base http.RoundTripper for CLI HTTP clients.
 //
 // By default it returns http.DefaultTransport — the stdlib-provided
@@ -99,6 +128,23 @@ var noProxyTransport = sync.OnceValue(func() *http.Transport {
 // goroutines are reused; cloning per call leaks them until IdleConnTimeout
 // (~90s) fires.
 func SharedTransport() http.RoundTripper {
+	// SEC plugin mode overrides all other proxy behavior (env proxies and
+	// LARK_CLI_NO_PROXY), per operator intent.
+	if cfg, err := secplugin.Load(); err != nil {
+		// Fail closed: if the config file exists but is malformed/unreadable,
+		// do not silently fall back to direct egress.
+		def, ok := http.DefaultTransport.(*http.Transport)
+		if !ok {
+			return http.DefaultTransport
+		}
+		blocked := def.Clone()
+		blocked.Proxy = func(*http.Request) (*url.URL, error) {
+			return nil, fmt.Errorf("sec plugin config is invalid: %v", err)
+		}
+		return blocked
+	} else if cfg != nil && cfg.Enabled() {
+		return secProxyTransport()
+	}
 	if os.Getenv(EnvNoProxy) != "" {
 		return noProxyTransport()
 	}

internal/util/proxy_test.go

@@ -6,11 +6,43 @@ package util
 import (
 	"bytes"
 	"net/http"
+	"os"
 	"sync"
 	"testing"
+
+	"github.com/larksuite/cli/internal/envvars"
 )
 
+// unsetEnv clears key for the duration of the test and restores its original value.
+func unsetEnv(t *testing.T, key string) {
+	t.Helper()
+	old, had := os.LookupEnv(key)
+	_ = os.Unsetenv(key)
+	t.Cleanup(func() {
+		if had {
+			_ = os.Setenv(key, old)
+		} else {
+			_ = os.Unsetenv(key)
+		}
+	})
+}
+
+// unsetSecPluginEnv clears SEC-related environment variables for deterministic tests.
+func unsetSecPluginEnv(t *testing.T) {
+	t.Helper()
+	// Ensure developer machine env doesn't accidentally enable SEC plugin mode
+	// and change expectations for SharedTransport().
+	unsetEnv(t, envvars.CliSecEnable)
+	unsetEnv(t, envvars.CliSecProxy)
+	unsetEnv(t, envvars.CliSecCA)
+	unsetEnv(t, envvars.CliSecAuth)
+}
+
+// TestDetectProxyEnv verifies proxy environment detection priority and empty-state behavior.
 func TestDetectProxyEnv(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
+
 	// Clear all proxy env vars first
 	for _, k := range proxyEnvKeys {
 		t.Setenv(k, "")
@@ -28,7 +60,10 @@ func TestDetectProxyEnv(t *testing.T) {
 	}
 }
 
+// TestSharedTransport_DefaultReturnsStdlibSingleton verifies the default shared transport.
 func TestSharedTransport_DefaultReturnsStdlibSingleton(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	t.Setenv(EnvNoProxy, "")
 	tr := SharedTransport()
 	if tr != http.DefaultTransport {
@@ -36,7 +71,10 @@ func TestSharedTransport_DefaultReturnsStdlibSingleton(t *testing.T) {
 	}
 }
 
+// TestSharedTransport_NoProxyReturnsClone verifies that disabling proxying returns a cloned transport.
 func TestSharedTransport_NoProxyReturnsClone(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	t.Setenv(EnvNoProxy, "1")
 	tr := SharedTransport()
 	if tr == http.DefaultTransport {
@@ -51,7 +89,10 @@ func TestSharedTransport_NoProxyReturnsClone(t *testing.T) {
 	}
 }
 
+// TestSharedTransport_NoProxyIsCachedSingleton verifies singleton caching for the no-proxy transport.
 func TestSharedTransport_NoProxyIsCachedSingleton(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	t.Setenv(EnvNoProxy, "1")
 	a := SharedTransport()
 	b := SharedTransport()
@@ -60,7 +101,10 @@ func TestSharedTransport_NoProxyIsCachedSingleton(t *testing.T) {
 	}
 }
 
+// TestSharedTransport_EnvUnsetAfterSetFallsBackToDefault verifies fallback to the stdlib transport after unsetting EnvNoProxy.
 func TestSharedTransport_EnvUnsetAfterSetFallsBackToDefault(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	// Simulate a process that first runs with LARK_CLI_NO_PROXY=1 (populating
 	// the no-proxy singleton), then unsets it. Subsequent calls must return
 	// http.DefaultTransport, NOT the cached no-proxy clone.
@@ -77,7 +121,10 @@ func TestSharedTransport_EnvUnsetAfterSetFallsBackToDefault(t *testing.T) {
 	}
 }
 
+// TestSharedTransport_NoProxyOverridesSystemProxy verifies that EnvNoProxy disables system proxies.
 func TestSharedTransport_NoProxyOverridesSystemProxy(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	t.Setenv("HTTPS_PROXY", "http://should-be-ignored:8888")
 	t.Setenv(EnvNoProxy, "1")
 
@@ -90,7 +137,10 @@ func TestSharedTransport_NoProxyOverridesSystemProxy(t *testing.T) {
 	}
 }
 
+// TestWarnIfProxied_WithProxy verifies that proxy detection emits a warning.
 func TestWarnIfProxied_WithProxy(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	// Reset the once guard for this test
 	proxyWarningOnce = sync.Once{}
 
@@ -111,7 +161,10 @@ func TestWarnIfProxied_WithProxy(t *testing.T) {
 	}
 }
 
+// TestWarnIfProxied_WithoutProxy verifies that no warning is emitted without proxy settings.
 func TestWarnIfProxied_WithoutProxy(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	proxyWarningOnce = sync.Once{}
 
 	for _, k := range proxyEnvKeys {
@@ -126,7 +179,10 @@ func TestWarnIfProxied_WithoutProxy(t *testing.T) {
 	}
 }
 
+// TestWarnIfProxied_SilentWhenDisabled verifies that EnvNoProxy suppresses warnings.
 func TestWarnIfProxied_SilentWhenDisabled(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	proxyWarningOnce = sync.Once{}
 
 	t.Setenv("HTTPS_PROXY", "http://proxy:8080")
@@ -140,7 +196,10 @@ func TestWarnIfProxied_SilentWhenDisabled(t *testing.T) {
 	}
 }
 
+// TestWarnIfProxied_OnlyOnce verifies that proxy warnings are emitted only once.
 func TestWarnIfProxied_OnlyOnce(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	proxyWarningOnce = sync.Once{}
 
 	t.Setenv("HTTP_PROXY", "http://proxy:1234")
@@ -160,7 +219,10 @@ func TestWarnIfProxied_OnlyOnce(t *testing.T) {
 	}
 }
 
+// TestRedactProxyURL verifies redaction of proxy credentials across supported formats.
 func TestRedactProxyURL(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	tests := []struct {
 		input string
 		want  string
@@ -183,7 +245,10 @@ func TestRedactProxyURL(t *testing.T) {
 	}
 }
 
+// TestWarnIfProxied_RedactsCredentials verifies that warning output never leaks credentials.
 func TestWarnIfProxied_RedactsCredentials(t *testing.T) {
+	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
+	unsetSecPluginEnv(t)
 	proxyWarningOnce = sync.Once{}
 
 	t.Setenv("HTTPS_PROXY", "http://admin:s3cret@proxy:8080")

main.go

@@ -9,7 +9,8 @@ import (
 
 	"github.com/larksuite/cli/cmd"
 
-	_ "github.com/larksuite/cli/extension/credential/env" // activate env credential provider
+	_ "github.com/larksuite/cli/extension/credential/env"       // activate env credential provider
+	_ "github.com/larksuite/cli/extension/credential/secplugin" // activate sec plugin credential provider (SEC_AUTH placeholder tokens)
 )
 
 func main() {