diff --git a/internal/cmdutil/factory_default.go b/internal/cmdutil/factory_default.go
index 514aaf93f..39f8a7b50 100644
--- a/internal/cmdutil/factory_default.go
+++ b/internal/cmdutil/factory_default.go
@@ -102,7 +102,7 @@ func safeRedirectPolicy(req *http.Request, via []*http.Request) error {
 
 func cachedHttpClientFunc(f *Factory) func() (*http.Client, error) {
 	return sync.OnceValues(func() (*http.Client, error) {
-		transport.WarnIfProxied(f.IOStreams.ErrOut)
+		transport.WarnIfProxied(f.IOStreams.ErrOut, f.IOStreams.IsTerminal)
 
 		var rt http.RoundTripper = transport.Shared()
 		rt = &RetryTransport{Base: rt}
@@ -129,7 +129,7 @@ func cachedLarkClientFunc(f *Factory) func() (*lark.Client, error) {
 			lark.WithLogLevel(larkcore.LogLevelError),
 			lark.WithHeaders(BaseSecurityHeaders()),
 		}
-		transport.WarnIfProxied(f.IOStreams.ErrOut)
+		transport.WarnIfProxied(f.IOStreams.ErrOut, f.IOStreams.IsTerminal)
 		opts = append(opts, lark.WithHttpClient(&http.Client{
 			Transport:     buildSDKTransport(),
 			CheckRedirect: safeRedirectPolicy,
diff --git a/internal/transport/warn.go b/internal/transport/warn.go
index cac050f72..9cb68688f 100644
--- a/internal/transport/warn.go
+++ b/internal/transport/warn.go
@@ -73,7 +73,18 @@ func redactProxyURL(raw string) string {
 // WarnIfProxied prints a one-time warning to w when a proxy environment variable
 // is detected and proxy is not disabled via LARK_CLI_NO_PROXY. Proxy credentials
 // are redacted. Safe to call multiple times; only the first call prints.
-func WarnIfProxied(w io.Writer) {
+//
+// The warning is suppressed entirely when interactive is false — i.e. stdin is
+// not a TTY, which is the case for agent / CI / piped invocations. Those callers
+// frequently parse the CLI's stdout as JSON and merge streams with `2>&1`; a
+// stray stderr warning then corrupts the parsed payload. Suppressing in the
+// non-interactive case keeps machine-consumed output clean, while human
+// interactive sessions still get the security notice. Passing interactive=false
+// does not consume the once guard, so a later interactive call can still warn.
+func WarnIfProxied(w io.Writer, interactive bool) {
+	if !interactive {
+		return
+	}
 	proxyWarningOnce.Do(func() {
 		// Proxy plugin mode overrides env proxies and LARK_CLI_NO_PROXY (see
 		// Shared), so its warning and disable instructions take precedence.
diff --git a/internal/transport/warn_test.go b/internal/transport/warn_test.go
index 13708ca7e..6f1eb530c 100644
--- a/internal/transport/warn_test.go
+++ b/internal/transport/warn_test.go
@@ -44,7 +44,7 @@ func TestWarnIfProxied_WithProxy(t *testing.T) {
 	t.Setenv("HTTPS_PROXY", "http://corp-proxy:3128")
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 
 	out := buf.String()
 	if out == "" {
@@ -70,13 +70,30 @@ func TestWarnIfProxied_WithoutProxy(t *testing.T) {
 	}
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 
 	if buf.Len() != 0 {
 		t.Errorf("expected no output when no proxy is set, got: %s", buf.String())
 	}
 }
 
+func TestWarnIfProxied_SilentWhenNonInteractive(t *testing.T) {
+	proxyWarningOnce = sync.Once{}
+
+	// Non-interactive (interactive=false) mirrors agent / CI / piped invocations
+	// where stdin is not a TTY. The proxy warning must be suppressed so callers
+	// that parse stdout as JSON — often merging streams with `2>&1` — are not
+	// corrupted by a stray stderr line.
+	t.Setenv("HTTPS_PROXY", "http://corp-proxy:3128")
+
+	var buf bytes.Buffer
+	WarnIfProxied(&buf, false)
+
+	if buf.Len() != 0 {
+		t.Errorf("expected no warning in non-interactive mode, got: %s", buf.String())
+	}
+}
+
 // TestWarnIfProxied_SilentWhenDisabled verifies that LARK_CLI_NO_PROXY suppresses warnings.
 func TestWarnIfProxied_SilentWhenDisabled(t *testing.T) {
 	t.Setenv("LARKSUITE_CLI_CONFIG_DIR", t.TempDir())
@@ -88,7 +105,7 @@ func TestWarnIfProxied_SilentWhenDisabled(t *testing.T) {
 	t.Setenv(EnvNoProxy, "1")
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 
 	if buf.Len() != 0 {
 		t.Errorf("expected no warning when proxy is disabled, got: %s", buf.String())
@@ -105,10 +122,10 @@ func TestWarnIfProxied_OnlyOnce(t *testing.T) {
 	t.Setenv("HTTP_PROXY", "http://proxy:1234")
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 	first := buf.String()
 
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 	second := buf.String()
 
 	if first == "" {
@@ -137,7 +154,7 @@ func TestWarnIfProxied_ProxyPluginEnabled(t *testing.T) {
 	t.Setenv(EnvNoProxy, "1")
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 	out := buf.String()
 
 	if !strings.Contains(out, "127.0.0.1:3128") {
@@ -169,7 +186,7 @@ func TestWarnIfProxied_ProxyPluginCustomCAWarns(t *testing.T) {
 	t.Cleanup(func() { proxyPluginStatus = old })
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 	out := buf.String()
 
 	if !strings.Contains(out, "custom CA") {
@@ -195,7 +212,7 @@ func TestWarnIfProxied_ProxyPluginEnabledRedactsCredentials(t *testing.T) {
 	t.Cleanup(func() { proxyPluginStatus = old })
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 	out := buf.String()
 
 	if strings.Contains(out, "s3cret") {
@@ -243,7 +260,7 @@ func TestWarnIfProxied_RedactsCredentials(t *testing.T) {
 	t.Setenv("HTTPS_PROXY", "http://admin:s3cret@proxy:8080")
 
 	var buf bytes.Buffer
-	WarnIfProxied(&buf)
+	WarnIfProxied(&buf, true)
 
 	out := buf.String()
 	if bytes.Contains([]byte(out), []byte("s3cret")) {