diff --git a/experimental/ssh/internal/client/client.go b/experimental/ssh/internal/client/client.go
index 3cecb9c30e..67b20aa84d 100644
--- a/experimental/ssh/internal/client/client.go
+++ b/experimental/ssh/internal/client/client.go
@@ -1150,6 +1150,14 @@ func ensureSSHServerIsRunning(ctx context.Context, client *databricks.WorkspaceC
 }
 
 func logSshTunnelEvent(ctx context.Context, opts ClientOptions, isSuccess, isReconnect bool, serverStartTimeMs int64) {
+	telemetry.Log(ctx, protos.DatabricksCliLog{
+		SshTunnelEvent: buildSshTunnelEvent(opts, isSuccess, isReconnect, serverStartTimeMs),
+	})
+}
+
+// buildSshTunnelEvent maps the connection options and outcome onto the telemetry
+// event. It is separated from logSshTunnelEvent so the field mapping can be unit tested.
+func buildSshTunnelEvent(opts ClientOptions, isSuccess, isReconnect bool, serverStartTimeMs int64) *protos.SshTunnelEvent {
 	computeType := protos.SshTunnelComputeTypeDedicated
 	if opts.IsServerlessMode() {
 		computeType = protos.SshTunnelComputeTypeServerless
@@ -1165,16 +1173,15 @@ func logSshTunnelEvent(ctx context.Context, opts ClientOptions, isSuccess, isRec
 		clientMode = protos.SshTunnelClientModeSSH
 	}
 
-	telemetry.Log(ctx, protos.DatabricksCliLog{
-		SshTunnelEvent: &protos.SshTunnelEvent{
-			ComputeType:       computeType,
-			AcceleratorType:   opts.Accelerator,
-			IdeType:           opts.IDE,
-			ClientMode:        clientMode,
-			IsReconnect:       isReconnect,
-			AutoStartCluster:  opts.AutoStartCluster,
-			ServerStartTimeMs: serverStartTimeMs,
-			IsSuccess:         isSuccess,
-		},
-	})
+	return &protos.SshTunnelEvent{
+		ComputeType:        computeType,
+		AcceleratorType:    opts.Accelerator,
+		IdeType:            opts.IDE,
+		ClientMode:         clientMode,
+		IsReconnect:        isReconnect,
+		AutoStartCluster:   opts.AutoStartCluster,
+		ServerStartTimeMs:  serverStartTimeMs,
+		IsSuccess:          isSuccess,
+		HasBaseEnvironment: opts.BaseEnvironment != "",
+	}
 }
diff --git a/experimental/ssh/internal/client/client_internal_test.go b/experimental/ssh/internal/client/client_internal_test.go
index 57861eb25c..f71f38d089 100644
--- a/experimental/ssh/internal/client/client_internal_test.go
+++ b/experimental/ssh/internal/client/client_internal_test.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/databricks/cli/libs/cmdio"
+	"github.com/databricks/cli/libs/telemetry/protos"
 	"github.com/databricks/databricks-sdk-go/experimental/mocks"
 	"github.com/databricks/databricks-sdk-go/service/compute"
 	"github.com/databricks/databricks-sdk-go/service/environments"
@@ -416,3 +417,68 @@ func TestTailWriterRetainsTail(t *testing.T) {
 		assert.Equal(t, "ab", w.String())
 	})
 }
+
+func TestBuildSshTunnelEvent(t *testing.T) {
+	tests := []struct {
+		name string
+		opts ClientOptions
+		want protos.SshTunnelEvent
+	}{
+		{
+			name: "dedicated cluster via raw SSH client",
+			opts: ClientOptions{ClusterID: "abc-123", AutoStartCluster: true},
+			want: protos.SshTunnelEvent{
+				ComputeType:      protos.SshTunnelComputeTypeDedicated,
+				ClientMode:       protos.SshTunnelClientModeSSH,
+				AutoStartCluster: true,
+			},
+		},
+		{
+			name: "serverless with accelerator",
+			opts: ClientOptions{ConnectionName: "my-conn", Accelerator: "GPU_1xA10"},
+			want: protos.SshTunnelEvent{
+				ComputeType:     protos.SshTunnelComputeTypeServerless,
+				AcceleratorType: "GPU_1xA10",
+				ClientMode:      protos.SshTunnelClientModeSSH,
+			},
+		},
+		{
+			name: "proxy mode takes precedence over IDE",
+			opts: ClientOptions{ConnectionName: "my-conn", ProxyMode: true, IDE: "vscode"},
+			want: protos.SshTunnelEvent{
+				ComputeType: protos.SshTunnelComputeTypeServerless,
+				IdeType:     "vscode",
+				ClientMode:  protos.SshTunnelClientModeProxy,
+			},
+		},
+		{
+			name: "IDE mode",
+			opts: ClientOptions{ConnectionName: "my-conn", IDE: "cursor"},
+			want: protos.SshTunnelEvent{
+				ComputeType: protos.SshTunnelComputeTypeServerless,
+				IdeType:     "cursor",
+				ClientMode:  protos.SshTunnelClientModeIDE,
+			},
+		},
+		{
+			// The raw --base-environment value can carry PII, so only its presence is recorded.
+			name: "custom base environment records presence only",
+			opts: ClientOptions{ConnectionName: "my-conn", BaseEnvironment: "/Workspace/Users/me@example.com/env.yaml"},
+			want: protos.SshTunnelEvent{
+				ComputeType:        protos.SshTunnelComputeTypeServerless,
+				ClientMode:         protos.SshTunnelClientModeSSH,
+				HasBaseEnvironment: true,
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := buildSshTunnelEvent(tt.opts, true, true, 1500)
+			tt.want.IsSuccess = true
+			tt.want.IsReconnect = true
+			tt.want.ServerStartTimeMs = 1500
+			assert.Equal(t, &tt.want, got)
+		})
+	}
+}
diff --git a/libs/telemetry/protos/ssh_tunnel.go b/libs/telemetry/protos/ssh_tunnel.go
index 42be8233b7..062bc0fff4 100644
--- a/libs/telemetry/protos/ssh_tunnel.go
+++ b/libs/telemetry/protos/ssh_tunnel.go
@@ -38,6 +38,11 @@ type SshTunnelEvent struct {
 	// Whether the cluster was auto-started by the CLI.
 	AutoStartCluster bool `json:"auto_start_cluster,omitempty"`
 
+	// Whether a custom base environment was set via --base-environment.
+	// Only the presence is recorded: the flag value can be an env.yaml path
+	// or display name carrying PII, so the value itself is not logged.
+	HasBaseEnvironment bool `json:"has_base_environment,omitempty"`
+
 	// Time in milliseconds spent starting the SSH server.
 	// Zero if server was already running.
 	ServerStartTimeMs int64 `json:"server_start_time_ms"`