diff --git a/cliext/flags.gen.go b/cliext/flags.gen.go
index 28668a3ed..c607e4c13 100644
--- a/cliext/flags.gen.go
+++ b/cliext/flags.gen.go
@@ -38,8 +38,8 @@ func (v *CommonOptions) BuildFlags(f *pflag.FlagSet) {
 	f.StringVar(&v.Profile, "profile", "", "Profile to use for config file. EXPERIMENTAL.")
 	f.BoolVar(&v.DisableConfigFile, "disable-config-file", false, "If set, disables loading environment config from config file. EXPERIMENTAL.")
 	f.BoolVar(&v.DisableConfigEnv, "disable-config-env", false, "If set, disables loading environment config from environment variables. EXPERIMENTAL.")
-	v.LogLevel = NewFlagStringEnum([]string{"debug", "info", "warn", "error", "never"}, "info")
-	f.Var(&v.LogLevel, "log-level", "Log level. Default is \"info\" for most commands and \"warn\" for \"server start-dev\". Accepted values: debug, info, warn, error, never.")
+	v.LogLevel = NewFlagStringEnum([]string{"debug", "info", "warn", "error", "never"}, "never")
+	f.Var(&v.LogLevel, "log-level", "Log level. Default is \"never\" for most commands and \"warn\" for \"server start-dev\". Accepted values: debug, info, warn, error, never.")
 	v.LogFormat = NewFlagStringEnum([]string{"text", "json", "pretty"}, "text")
 	f.Var(&v.LogFormat, "log-format", "Log format. Accepted values: text, json.")
 	v.Output = NewFlagStringEnum([]string{"text", "json", "jsonl", "none"}, "text")
diff --git a/cliext/option-sets.yaml b/cliext/option-sets.yaml
index c8472fd03..e7a7ff8cf 100644
--- a/cliext/option-sets.yaml
+++ b/cliext/option-sets.yaml
@@ -51,8 +51,8 @@ option-sets:
           - never
         description: |
           Log level.
-          Default is "info" for most commands and "warn" for "server start-dev".
-        default: info
+          Default is "never" for most commands and "warn" for "server start-dev".
+        default: never
       - name: log-format
         type: string-enum
         description: Log format.
diff --git a/internal/temporalcli/commands.env.go b/internal/temporalcli/commands.env.go
index d98c06f04..5d43843d7 100644
--- a/internal/temporalcli/commands.env.go
+++ b/internal/temporalcli/commands.env.go
@@ -13,7 +13,7 @@ import (
 
 func (c *TemporalEnvCommand) envNameAndKey(cctx *CommandContext, args []string, keyFlag string) (string, string, error) {
 	if len(args) > 0 {
-		cctx.Logger.Warn("Arguments to env commands are deprecated; please use --env and --key (or -k) instead")
+		fmt.Fprintln(cctx.Options.Stderr, "Warning: Arguments to env commands are deprecated; please use --env and --key (or -k) instead")
 
 		if c.Parent.Env != "default" || keyFlag != "" {
 			return "", "", fmt.Errorf("cannot specify both an argument and flags; please use flags instead")
diff --git a/internal/temporalcli/commands.env_test.go b/internal/temporalcli/commands.env_test.go
index cdd1157a9..1a2a0a45a 100644
--- a/internal/temporalcli/commands.env_test.go
+++ b/internal/temporalcli/commands.env_test.go
@@ -2,6 +2,7 @@ package temporalcli_test
 
 import (
 	"os"
+	"strings"
 	"testing"
 
 	"gopkg.in/yaml.v3"
@@ -104,3 +105,53 @@ func TestEnv_InputValidation(t *testing.T) {
 	res = h.Execute("env", "set", "myenv1.foo")
 	h.ErrorContains(res.Err, `no value provided`)
 }
+
+func TestEnv_DeprecationWarningBypassesLogger(t *testing.T) {
+	h := NewCommandHarness(t)
+	defer h.Close()
+
+	tmpFile, err := os.CreateTemp("", "")
+	h.NoError(err)
+	h.Options.DeprecatedEnvConfig.EnvConfigFile = tmpFile.Name()
+	defer os.Remove(h.Options.DeprecatedEnvConfig.EnvConfigFile)
+	res := h.Execute("env", "set", "--env", "myenv1", "-k", "foo", "-v", "bar")
+	h.NoError(res.Err)
+
+	// Using deprecated argument syntax should produce a warning on stderr.
+	// The warning must bypass the logger so it appears regardless of log level.
+	for _, logLevel := range []string{"never", "error", "info"} {
+		t.Run("log-level="+logLevel, func(t *testing.T) {
+			res = h.Execute("env", "get", "--log-level", logLevel, "myenv1")
+			h.NoError(res.Err)
+
+			stderr := res.Stderr.String()
+			h.Contains(stderr, "Warning:")
+			h.Contains(stderr, "deprecated")
+
+			// Must be a plain-text warning, not a structured log message
+			h.False(strings.Contains(stderr, "time="), "warning should not be a structured log message")
+			h.False(strings.Contains(stderr, "level="), "warning should not be a structured log message")
+		})
+	}
+}
+
+func TestEnv_DefaultLogLevelProducesNoLogOutput(t *testing.T) {
+	h := NewCommandHarness(t)
+	defer h.Close()
+
+	tmpFile, err := os.CreateTemp("", "")
+	h.NoError(err)
+	h.Options.DeprecatedEnvConfig.EnvConfigFile = tmpFile.Name()
+	defer os.Remove(h.Options.DeprecatedEnvConfig.EnvConfigFile)
+
+	// env set logs "Setting env property" via cctx.Logger.Info(). With the
+	// default log level ("never"), this should not appear on stderr.
+	res := h.Execute("env", "set", "--env", "myenv1", "-k", "foo", "-v", "bar")
+	h.NoError(res.Err)
+	h.Empty(res.Stderr.String(), "default log level should produce no log output")
+
+	// With --log-level info, the logger output should appear.
+	res = h.Execute("env", "set", "--env", "myenv1", "-k", "baz", "-v", "qux", "--log-level", "info")
+	h.NoError(res.Err)
+	h.Contains(res.Stderr.String(), "Setting env property")
+}
diff --git a/internal/temporalcli/commands.go b/internal/temporalcli/commands.go
index a60307b83..1983ebdfa 100644
--- a/internal/temporalcli/commands.go
+++ b/internal/temporalcli/commands.go
@@ -143,11 +143,7 @@ func (c *CommandContext) preprocessOptions() error {
 			if c.Err() != nil {
 				err = fmt.Errorf("program interrupted")
 			}
-			if c.Logger != nil {
-				c.Logger.Error(err.Error())
-			} else {
-				fmt.Fprintln(os.Stderr, err)
-			}
+			fmt.Fprintf(c.Options.Stderr, "Error: %v\n", err)
 			os.Exit(1)
 		}
 	}
diff --git a/internal/temporalcli/commands.operator_namespace.go b/internal/temporalcli/commands.operator_namespace.go
index ebcc96cab..ca4b6c6d5 100644
--- a/internal/temporalcli/commands.operator_namespace.go
+++ b/internal/temporalcli/commands.operator_namespace.go
@@ -19,7 +19,7 @@ func (c *TemporalOperatorCommand) getNSFromFlagOrArg0(cctx *CommandContext, args
 	}
 
 	if len(args) > 0 {
-		cctx.Logger.Warn("Passing the namespace as an argument is now deprecated; please switch to using -n instead")
+		fmt.Fprintln(cctx.Options.Stderr, "Warning: Passing the namespace as an argument is now deprecated; please switch to using -n instead")
 		return args[0], nil
 	}
 	return c.Namespace, nil
diff --git a/internal/temporalcli/commands.workflow_exec.go b/internal/temporalcli/commands.workflow_exec.go
index d5ba34899..935504b96 100644
--- a/internal/temporalcli/commands.workflow_exec.go
+++ b/internal/temporalcli/commands.workflow_exec.go
@@ -94,7 +94,7 @@ func (c *TemporalWorkflowExecuteCommand) run(cctx *CommandContext, args []string
 	// Log print failure and return workflow failure if workflow failed
 	if closeEvent.EventType != enums.EVENT_TYPE_WORKFLOW_EXECUTION_COMPLETED {
 		if err != nil {
-			cctx.Logger.Error("Workflow failed, and printing the output also failed", "error", err)
+			fmt.Fprintf(cctx.Options.Stderr, "Warning: printing workflow output failed: %v\n", err)
 		}
 		err = fmt.Errorf("workflow failed")
 	}
diff --git a/internal/temporalcli/commands.workflow_view.go b/internal/temporalcli/commands.workflow_view.go
index 08fb5c76e..a63ca06ec 100644
--- a/internal/temporalcli/commands.workflow_view.go
+++ b/internal/temporalcli/commands.workflow_view.go
@@ -560,7 +560,7 @@ func (c *TemporalWorkflowResultCommand) run(cctx *CommandContext, _ []string) er
 	// Log print failure and return workflow failure if workflow failed
 	if closeEvent.EventType != enums.EVENT_TYPE_WORKFLOW_EXECUTION_COMPLETED {
 		if err != nil {
-			cctx.Logger.Error("Workflow failed, and printing the output also failed", "error", err)
+			fmt.Fprintf(cctx.Options.Stderr, "Warning: printing workflow output failed: %v\n", err)
 		}
 		err = fmt.Errorf("workflow failed")
 	}
diff --git a/internal/temporalcli/commands_test.go b/internal/temporalcli/commands_test.go
index 2312e442e..749f2c3e6 100644
--- a/internal/temporalcli/commands_test.go
+++ b/internal/temporalcli/commands_test.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"log/slog"
+	"net"
 	"regexp"
 	"slices"
 	"strings"
@@ -625,6 +626,30 @@ func TestUnknownCommandExitsNonzero(t *testing.T) {
 	assert.Contains(t, res.Err.Error(), "unknown command")
 }
 
+func TestErrorReporting_IndependentOfLogLevel(t *testing.T) {
+	// Errors must be reported through Fail regardless of --log-level, and
+	// must not produce structured log output on stderr.
+	for _, logLevel := range []string{"never", "error", "info"} {
+		t.Run("log-level="+logLevel, func(t *testing.T) {
+			h := NewCommandHarness(t)
+			ln, err := net.Listen("tcp", "127.0.0.1:0")
+			require.NoError(t, err)
+			ln.Close() // close immediately so connection is refused
+
+			res := h.Execute(
+				"workflow", "list",
+				"--address", ln.Addr().String(),
+				"--log-level", logLevel,
+			)
+			require.Error(t, res.Err)
+
+			stderr := res.Stderr.String()
+			assert.NotContains(t, stderr, "level=ERROR",
+				"errors should not appear as structured log messages on stderr")
+		})
+	}
+}
+
 func (s *SharedServerSuite) TestHiddenAliasLogFormat() {
 	_ = s.waitActivityStarted().GetID()
 	res := s.Execute("workflow", "list", "--log-format", "pretty", "--address", s.Address())