diff --git a/shortcuts/sheets/csv_put_stdin_fallback_test.go b/shortcuts/sheets/csv_put_stdin_fallback_test.go
deleted file mode 100644
index b9764db50..000000000
--- a/shortcuts/sheets/csv_put_stdin_fallback_test.go
+++ /dev/null
@@ -1,115 +0,0 @@
-// Copyright (c) 2026 Lark Technologies Pte. Ltd.
-// SPDX-License-Identifier: MIT
-
-package sheets
-
-import (
-	"testing"
-
-	"github.com/larksuite/cli/internal/cmdutil"
-	"github.com/spf13/cobra"
-)
-
-// +csv-put lets a piped CSV satisfy an omitted --csv: agents routinely redirect
-// a file into stdin but forget the `--csv -`. PostMount relaxes the required
-// gate and installs a PreRunE that, when stdin is a non-interactive pipe,
-// defaults an absent --csv to "-" so the standard stdin path reads it. On an
-// interactive terminal the fallback stays off so the command never blocks.
-func mountCsvPut(t *testing.T) *cobra.Command {
-	t.Helper()
-	f, _, _, _ := cmdutil.TestFactory(t, nil)
-	parent := &cobra.Command{Use: "sheets"}
-	CsvPut.Mount(parent, f)
-	cmd, _, err := parent.Find([]string{"+csv-put"})
-	if err != nil {
-		t.Fatalf("Find(+csv-put) error = %v", err)
-	}
-	return cmd
-}
-
-func csvRequiredAnnotationPresent(cmd *cobra.Command) bool {
-	fl := cmd.Flags().Lookup("csv")
-	if fl == nil {
-		return false
-	}
-	_, ok := fl.Annotations[cobra.BashCompOneRequiredFlag]
-	return ok
-}
-
-// withStdinIsPipe swaps the package-level pipe detector for the duration of a
-// test so behavior does not depend on the real process stdin.
-func withStdinIsPipe(t *testing.T, piped bool) {
-	t.Helper()
-	prev := csvPutStdinIsPipe
-	csvPutStdinIsPipe = func() bool { return piped }
-	t.Cleanup(func() { csvPutStdinIsPipe = prev })
-}
-
-func TestCsvPutPostMount_RelaxesCsvRequired(t *testing.T) {
-	cmd := mountCsvPut(t)
-	if csvRequiredAnnotationPresent(cmd) {
-		t.Error("--csv required annotation should be relaxed so csvPutInput reports the typed error")
-	}
-	if cmd.PreRunE == nil {
-		t.Fatal("PostMount should install a PreRunE for the stdin fallback")
-	}
-}
-
-func TestCsvPutPreRunE_PipedAbsentDefaultsToDash(t *testing.T) {
-	withStdinIsPipe(t, true)
-	cmd := mountCsvPut(t)
-	if err := cmd.PreRunE(cmd, nil); err != nil {
-		t.Fatalf("PreRunE error = %v", err)
-	}
-	if got, _ := cmd.Flags().GetString("csv"); got != "-" {
-		t.Errorf("csv = %q, want %q (piped + absent should default to '-')", got, "-")
-	}
-}
-
-func TestCsvPutPreRunE_InteractiveAbsentStaysEmpty(t *testing.T) {
-	withStdinIsPipe(t, false)
-	cmd := mountCsvPut(t)
-	if err := cmd.PreRunE(cmd, nil); err != nil {
-		t.Fatalf("PreRunE error = %v", err)
-	}
-	if got, _ := cmd.Flags().GetString("csv"); got != "" {
-		t.Errorf("csv = %q, want empty (interactive stdin must not be consumed / must not hang)", got)
-	}
-}
-
-func TestCsvPutPreRunE_ExplicitValueUnchanged(t *testing.T) {
-	withStdinIsPipe(t, true)
-	cmd := mountCsvPut(t)
-	if err := cmd.Flags().Set("csv", "x,y"); err != nil {
-		t.Fatalf("Set(csv) error = %v", err)
-	}
-	if err := cmd.PreRunE(cmd, nil); err != nil {
-		t.Fatalf("PreRunE error = %v", err)
-	}
-	if got, _ := cmd.Flags().GetString("csv"); got != "x,y" {
-		t.Errorf("csv = %q, want %q (explicit value must not be overridden)", got, "x,y")
-	}
-}
-
-func TestCsvPutPostMount_ComposesExistingPreRunE(t *testing.T) {
-	withStdinIsPipe(t, true)
-	cmd := &cobra.Command{Use: "+csv-put"}
-	cmd.Flags().String("start-cell", "", "")
-	cmd.Flags().String("range", "", "")
-	cmd.Flags().String("csv", "", "")
-	called := false
-	cmd.PreRunE = func(*cobra.Command, []string) error {
-		called = true
-		return nil
-	}
-	CsvPut.PostMount(cmd)
-	if err := cmd.PreRunE(cmd, nil); err != nil {
-		t.Fatalf("PreRunE error = %v", err)
-	}
-	if !called {
-		t.Fatal("existing PreRunE was not called")
-	}
-	if got, _ := cmd.Flags().GetString("csv"); got != "-" {
-		t.Fatalf("csv = %q, want fallback after existing PreRunE", got)
-	}
-}
diff --git a/shortcuts/sheets/lark_sheet_write_cells.go b/shortcuts/sheets/lark_sheet_write_cells.go
index f5a83ec70..5415dcbad 100644
--- a/shortcuts/sheets/lark_sheet_write_cells.go
+++ b/shortcuts/sheets/lark_sheet_write_cells.go
@@ -11,7 +11,6 @@ import (
 	_ "image/gif"
 	_ "image/jpeg"
 	_ "image/png"
-	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -204,19 +203,6 @@ func cellsSetStyleInput(runtime flagView, token, sheetID, sheetName string) (map
 	return input, nil
 }
 
-// csvPutStdinIsPipe reports whether process stdin is a non-interactive pipe or
-// redirect (rather than an interactive terminal), so an omitted --csv can be
-// satisfied from it without risking a hang on a real terminal. Overridable in
-// tests. A char device is a terminal; anything else (pipe, redirect, /dev/null)
-// counts as piped input.
-var csvPutStdinIsPipe = func() bool {
-	fi, err := os.Stdin.Stat() //nolint:forbidigo // pipe detection needs the real process fd; IOStreams.In is a plain io.Reader without Stat
-	if err != nil {
-		return false
-	}
-	return fi.Mode()&os.ModeCharDevice == 0
-}
-
 // CsvPut wraps set_range_from_csv: dump a CSV blob into a sheet. A cell whose
 // text starts with = is evaluated as a formula; use +cells-set for styles / notes / images.
 var CsvPut = common.Shortcut{
@@ -239,33 +225,6 @@ var CsvPut = common.Shortcut{
 		}
 		cmd.MarkFlagsOneRequired("start-cell", "range")
 		cmd.MarkFlagsMutuallyExclusive("start-cell", "range")
-
-		// Let a piped CSV satisfy --csv when the flag is omitted: agents
-		// routinely redirect a file into stdin but forget the `--csv -`, so
-		// `+csv-put ... < data.csv` would otherwise fail its first try on a
-		// missing --csv. Relax the required-gate (flag-defs marks --csv
-		// required) so an absent value surfaces csvPutInput's own typed error
-		// instead of cobra's bare "required flag(s) ... not set"; then, in
-		// PreRunE (which cobra runs before it validates required flags), default
-		// an omitted --csv to "-" when stdin is a non-interactive pipe so the
-		// standard stdin-resolution path reads it. The pipe guard means an
-		// interactive terminal never blocks waiting on stdin — a real miss still
-		// errors.
-		if fl := cmd.Flags().Lookup("csv"); fl != nil {
-			delete(fl.Annotations, cobra.BashCompOneRequiredFlag)
-		}
-		prev := cmd.PreRunE
-		cmd.PreRunE = func(c *cobra.Command, args []string) error {
-			if prev != nil {
-				if err := prev(c, args); err != nil {
-					return err
-				}
-			}
-			if v, _ := c.Flags().GetString("csv"); strings.TrimSpace(v) == "" && csvPutStdinIsPipe() {
-				_ = c.Flags().Set("csv", "-")
-			}
-			return nil
-		}
 	},
 	Validate: func(ctx context.Context, runtime *common.RuntimeContext) error {
 		if err := guardCSVValueIsNotFilePath(runtime); err != nil {
diff --git a/shortcuts/sheets/lark_sheet_write_cells_test.go b/shortcuts/sheets/lark_sheet_write_cells_test.go
index c36f59fd4..8c384d1d8 100644
--- a/shortcuts/sheets/lark_sheet_write_cells_test.go
+++ b/shortcuts/sheets/lark_sheet_write_cells_test.go
@@ -116,6 +116,18 @@ func TestWriteCellsShortcuts_DryRun(t *testing.T) {
 	}
 }
 
+func TestCsvPut_MissingCSVFailsRequiredGate(t *testing.T) {
+	t.Parallel()
+	_, _, err := runShortcutCapturingErr(t, CsvPut, []string{
+		"--url", testURL,
+		"--sheet-id", testSheetID,
+		"--start-cell", "A1",
+	})
+	if err == nil || !strings.Contains(err.Error(), "required flag(s) \"csv\" not set") {
+		t.Fatalf("missing --csv error = %v, want cobra required-flag error", err)
+	}
+}
+
 // TestDropdownSet_CellsShape inspects the 3×1 matrix produced from
 // --range A2:A4 to confirm the data_validation prototype is replicated.
 // Also covers --colors / --highlight emitting the canonical