diff --git a/repos/ports/run/gdb.inc b/repos/ports/run/gdb.inc
index 120e7c0508..0dc8ac392d 100644
--- a/repos/ports/run/gdb.inc
+++ b/repos/ports/run/gdb.inc
@@ -9,10 +9,7 @@ proc platform_supported { } {
 	return 0
 }
 
-if {![platform_supported]} {
-	puts "Run script is not supported on this platform"
-	exit 0
-}
+assert {[platform_supported]}
 
 proc gdb_pkg_name { } {
 	if {[have_spec arm_64]} {
diff --git a/repos/ports/run/lighttpd_fetchurl.run b/repos/ports/run/lighttpd_fetchurl.run
index d3647bbd0e..4dfef0829e 100644
--- a/repos/ports/run/lighttpd_fetchurl.run
+++ b/repos/ports/run/lighttpd_fetchurl.run
@@ -4,10 +4,8 @@
 # \date   2022-12-03
 #
 
-if {[have_board virt_qemu_riscv]} {
-	puts "Run script is not supported on this platform (missing curl and libssh)."
-	exit 0
-}
+assert {![have_board virt_qemu_riscv]} \
+	"Run script is not supported on this platform (missing curl and libssh)."
 
 proc ip_stack      { } { return lwip }
 proc download_size { } { return "1M" }
diff --git a/repos/ports/run/microcode.run b/repos/ports/run/microcode.run
index 8c7d53ab5e..b5b69b26ab 100644
--- a/repos/ports/run/microcode.run
+++ b/repos/ports/run/microcode.run
@@ -1,17 +1,15 @@
-assert_spec x86
+assert {[have_spec x86]}
 
 set path_microcode "[exec [genode_dir]/tool/ports/current --no-print-directory microcode_intel]/src/app/intel/intel-ucode"
 set microcode_files [glob -nocomplain -dir $path_microcode *-*-*]
 
-if { [get_cmd_switch --autopilot] } {
+if {[have_cmd_arg --autopilot]} {
 
-	if {[have_include "power_on/qemu"]} {
-		puts "\nRun script does not support Qemu.\n"
-		exit 0
-	}
+	assert {![have_include power_on/qemu]} \
+		"Autopilot mode is not supported on this platform."
 
 	# platform_info data about CPUs on other kernels missing
-	assert_spec nova
+	assert {[have_spec nova]}
 
 	if { [have_spec x86_64] } {
 		copy_file $path_microcode/06-3c-03 bin/micro.code
@@ -20,11 +18,10 @@ if { [get_cmd_switch --autopilot] } {
 	}
 }
 
-if {![file exists bin/micro.code]} {
-	puts "\nMissing bin/micro.code file for your target machine."
-	puts "Please select for your target CPU the microcode patch located in $path_microcode/xx-xx-xx."
-	puts "and copy it to bin/micro.code. xx-xx-xx stands for your target CPU, family-model-stepping\n"
-	exit 0
+assert {[file exists bin/micro.code]} {
+	Missing bin/micro.code file for your target machine.
+	Please select for your target CPU the microcode patch located in $path_microcode/xx-xx-xx.
+	and copy it to bin/micro.code. xx-xx-xx stands for your target CPU, family-model-stepping
 }
 
 proc apply_microcode { } { return true }
@@ -64,7 +61,7 @@ append qemu_args "-smp 4 "
 run_genode_until "microcode check done" 30
 
 # cleanup
-if { [get_cmd_switch --autopilot] } {
+if {[have_cmd_arg --autopilot]} {
 	file delete -force bin/micro.code
 	foreach file $microcode_files {
 	  file delete bin/$file
diff --git a/repos/ports/run/netperf.inc b/repos/ports/run/netperf.inc
index 75bba9b2dd..945c262c47 100644
--- a/repos/ports/run/netperf.inc
+++ b/repos/ports/run/netperf.inc
@@ -27,15 +27,9 @@
 #    ! sudo ip tuntap delete $TAP_DEV mode tap
 #
 
-if {[have_include "power_on/qemu"]} {
-	puts "\nRun script does not support Qemu.\n"
-	exit 0
-}
-
-if {[have_board imx53_qsb_tz] || [have_board rpi]} {
-	puts "Run script is not supported on this platform."
-	exit 0
-}
+assert {![have_include power_on/qemu]}
+assert {![have_board imx53_qsb_tz]}
+assert {![have_board rpi]}
 
 proc unique_byte_per_platform { } {
 
diff --git a/repos/ports/run/netperf_lwip_usb.run b/repos/ports/run/netperf_lwip_usb.run
index 0f8ddb6024..3e9f9a61a7 100644
--- a/repos/ports/run/netperf_lwip_usb.run
+++ b/repos/ports/run/netperf_lwip_usb.run
@@ -6,12 +6,10 @@
 #
 
 # our nightly test infrastructure currently support usb 3.0 on our x86 64bit machine only
-assert_spec x86_64
+assert {[have_spec x86_64]}
 
-if {[have_include "power_on/qemu"] || [have_include "power_on/linux"]} {
-	puts stderr "\nNetperf USB3.0 running on Qemu/Linux is not supported.\n"
-	exit 0
-}
+assert {![have_include power_on/qemu]}
+assert {![have_include power_on/linux]}
 
 # network configuration
 set use_nic_bridge      0
diff --git a/repos/ports/run/netperf_lwip_wifi.run b/repos/ports/run/netperf_lwip_wifi.run
index 99ba2a31ea..d236dc4580 100644
--- a/repos/ports/run/netperf_lwip_wifi.run
+++ b/repos/ports/run/netperf_lwip_wifi.run
@@ -4,17 +4,19 @@
 # \date   2013-07-08
 #
 
-assert_spec x86
+assert {[have_spec x86]}
 
-if {[have_include "power_on/qemu"] || [have_include "power_on/linux"]} {
-	puts stderr "\nNetperf WIFI running on Qemu/Linux is not supported.\n"
-	exit 0
-}
+assert {![have_include power_on/qemu]}
+assert {![have_include power_on/linux]}
 
-if {[get_cmd_switch --autopilot] && [have_spec x86_32] &&
-    ![expr [have_spec foc] || [have_spec nova]]} {
-	puts stderr "\nNetperf WIFI running with non-ACPI kernel on native x86_32 test machine is not supported because of wrong interrupt number in pci config space (should be 11 instead 10).\n"
-	exit
+if {[have_cmd_arg --autopilot] && [have_spec x86_32]} {
+	assert {[have_spec foc] || [have_spec nova]} {
+		Autopilot mode is not supported on this platform.
+
+		Netperf WIFI running with non-ACPI kernel on native x86_32 test
+		machine is not supported because of wrong interrupt number in
+		pci config space (should be 11 instead 10).
+	}
 }
 
 # network configuration
diff --git a/repos/ports/run/netperf_lxip_usb.run b/repos/ports/run/netperf_lxip_usb.run
index e289caf1bf..7aac8a9e0c 100644
--- a/repos/ports/run/netperf_lxip_usb.run
+++ b/repos/ports/run/netperf_lxip_usb.run
@@ -6,12 +6,10 @@
 #
 
 # our nightly test infrastructure currently support usb 3.0 on our x86 64bit machine only
-assert_spec x86_64
+assert {[have_spec x86_64]}
 
-if {[have_include "power_on/qemu"] || [have_include "power_on/linux"]} {
-	puts stderr "\nNetperf USB3.0 running on Qemu/Linux is not supported.\n"
-	exit 0
-}
+assert {![have_include power_on/qemu]}
+assert {![have_include power_on/linux]}
 
 # network configuration
 set use_nic_bridge      0
diff --git a/repos/ports/run/netperf_lxip_wifi.run b/repos/ports/run/netperf_lxip_wifi.run
index e6ab126dfa..9114826ed7 100644
--- a/repos/ports/run/netperf_lxip_wifi.run
+++ b/repos/ports/run/netperf_lxip_wifi.run
@@ -4,17 +4,19 @@
 # \date   2013-07-08
 #
 
-assert_spec x86
+assert {[have_spec x86]}
 
-if {[have_include "power_on/qemu"] || [have_include "power_on/linux"]} {
-	puts stderr "\nNetperf WIFI running on Qemu/Linux is not supported.\n"
-	exit 0
-}
+assert {![have_include power_on/qemu]}
+assert {![have_include power_on/linux]}
 
-if {[get_cmd_switch --autopilot] && [have_spec x86_32] &&
-    ![expr [have_spec foc] || [have_spec nova]]} {
-	puts stderr "\nNetperf WIFI running with non-ACPI kernel on native x86_32 test machine is not supported because of wrong interrupt number in pci config space (should be 11 instead 10).\n"
-	exit
+if {[have_cmd_arg --autopilot] && [have_spec x86_32]} {
+	assert {[have_spec foc] || [have_spec nova]} {
+		Autopilot mode is not supported on this platform.
+
+		Netperf WIFI running with non-ACPI kernel on native x86_32 test
+		machine is not supported because of wrong interrupt number in
+		pci config space (should be 11 instead 10).
+	}
 }
 
 # network configuration
diff --git a/repos/ports/run/socat.run b/repos/ports/run/socat.run
index c1d09119e4..fb8395ef63 100644
--- a/repos/ports/run/socat.run
+++ b/repos/ports/run/socat.run
@@ -1,16 +1,5 @@
-proc platform_supported { } {
-	if {[have_board pc]} {
-		return 1
-	} elseif {[have_board rpi3] && [have_include power_on/qemu]} {
-		return 1
-	}
-	return 0
-}
-
-if {![platform_supported]} {
-	puts "Run script is not supported on this platform"
-	exit 0
-}
+assert {([have_board pc]) ||
+        ([have_board rpi3] && [have_include power_on/qemu])}
 
 create_boot_directory
 
diff --git a/repos/ports/run/tool_chain_auto.run b/repos/ports/run/tool_chain_auto.run
index cecc183dba..499e2603c7 100644
--- a/repos/ports/run/tool_chain_auto.run
+++ b/repos/ports/run/tool_chain_auto.run
@@ -1,16 +1,14 @@
-if {[get_cmd_switch --autopilot] && [have_include "power_on/qemu"]} {
-	puts "\nRunning tool-chain auto test in autopilot on Qemu is not recommended."
-	exit 0
-}
-
-if {[have_spec pistachio] || [have_spec sel4] ||
-    [have_board imx53_qsb_tz] || [have_board rpi] ||
-    [expr [have_spec foc] && [have_board imx6q_sabrelite]] ||
-    [expr [have_spec foc] && [have_board imx7d_sabre]] } {
-	puts "Platform is unsupported."
-	exit 0
+if {[have_cmd_arg --autopilot]} {
+	assert {![have_include power_on/qemu]} \
+		"Running tool-chain auto test in autopilot on Qemu is not recommended."
 }
 
+assert {![have_spec pistachio]}
+assert {![have_spec sel4]}
+assert {![have_board imx53_qsb_tz]}
+assert {![have_board rpi]}
+assert {!([have_spec foc] && [have_board imx6q_sabrelite])}
+assert {!([have_spec foc] && [have_board imx7d_sabre])}
 
 create_boot_directory
 
diff --git a/repos/ports/run/vbox5_ubuntu_16_04_32.run b/repos/ports/run/vbox5_ubuntu_16_04_32.run
index 2a57e0da96..18821d5592 100644
--- a/repos/ports/run/vbox5_ubuntu_16_04_32.run
+++ b/repos/ports/run/vbox5_ubuntu_16_04_32.run
@@ -2,8 +2,8 @@
 # Ubuntu 16.04 32bit in VBox 5
 #
 
-assert_spec x86
-assert_spec nova
+assert {[have_spec x86]}
+assert {[have_spec nova]}
 
 set flavor   "ubuntu_16_04_32"
 set vm_ram   "1280M"
@@ -19,7 +19,7 @@ set use_overlay_from_disk 1
 set use_serial 1
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox5_ubuntu_16_04_64.run b/repos/ports/run/vbox5_ubuntu_16_04_64.run
index 7baa7e8e8a..93e070b434 100644
--- a/repos/ports/run/vbox5_ubuntu_16_04_64.run
+++ b/repos/ports/run/vbox5_ubuntu_16_04_64.run
@@ -2,8 +2,8 @@
 # Ubuntu 16.04 64bit in VBox 5
 #
 
-assert_spec x86_64
-assert_spec nova
+assert {[have_spec x86_64]}
+assert {[have_spec nova]}
 
 set flavor   "ubuntu_16_04_64"
 set vm_ram   "9460M"
@@ -19,7 +19,7 @@ set use_overlay_from_disk 1
 set use_serial 1
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox5_win10_64.run b/repos/ports/run/vbox5_win10_64.run
index 7f406d41b4..7a5602ff0a 100644
--- a/repos/ports/run/vbox5_win10_64.run
+++ b/repos/ports/run/vbox5_win10_64.run
@@ -2,8 +2,8 @@
 # Windows 10 in VirtualBox 5
 #
 
-assert_spec nova
-assert_spec x86_64
+assert {[have_spec nova]}
+assert {[have_spec x86_64]}
 
 set flavor   "win10_64"
 set vm_ram   "8280M"
@@ -19,7 +19,7 @@ set use_overlay_from_disk 1
 set use_serial 0
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox5_win7_32.run b/repos/ports/run/vbox5_win7_32.run
index d478f18a8c..6708051924 100644
--- a/repos/ports/run/vbox5_win7_32.run
+++ b/repos/ports/run/vbox5_win7_32.run
@@ -2,8 +2,8 @@
 # Windows 7 in VirtualBox 5
 #
 
-assert_spec nova
-assert_spec x86
+assert {[have_spec nova]}
+assert {[have_spec x86]}
 
 set flavor   "win7"
 set vm_ram   "1280M"
@@ -19,7 +19,7 @@ set use_overlay_from_disk 1
 set use_serial 0
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox5_win7_64.run b/repos/ports/run/vbox5_win7_64.run
index e993df149a..4c33604b66 100644
--- a/repos/ports/run/vbox5_win7_64.run
+++ b/repos/ports/run/vbox5_win7_64.run
@@ -2,8 +2,8 @@
 # Windows 7 64bit in VirtualBox
 #
 
-assert_spec x86_64
-assert_spec nova
+assert {[have_spec x86_64]}
+assert {[have_spec nova]}
 
 set flavor   "win7_64"
 set vm_ram   "9480M"
@@ -19,7 +19,7 @@ set use_overlay_from_disk 1
 set use_serial 0
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox5_win7_64_multiple.run b/repos/ports/run/vbox5_win7_64_multiple.run
index c03e276cb9..69b16aa263 100644
--- a/repos/ports/run/vbox5_win7_64_multiple.run
+++ b/repos/ports/run/vbox5_win7_64_multiple.run
@@ -12,8 +12,8 @@
 # ...
 # lCPU 6-7: VM6 2 vCPUs
 
-assert_spec x86_64
-assert_spec nova
+assert {[have_spec x86_64]}
+assert {[have_spec nova]}
 
 set flavor   "win7_64"
 set flavor_extension "_multiple"
@@ -30,7 +30,7 @@ set use_overlay_from_disk 1
 set use_serial 0
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 6
diff --git a/repos/ports/run/vbox5_win7_64_raw.run b/repos/ports/run/vbox5_win7_64_raw.run
index cc288b56ec..bae52ce5ef 100644
--- a/repos/ports/run/vbox5_win7_64_raw.run
+++ b/repos/ports/run/vbox5_win7_64_raw.run
@@ -2,8 +2,8 @@
 # Windows 7 64bit in VirtualBox
 #
 
-assert_spec x86_64
-assert_spec nova
+assert {[have_spec x86_64]}
+assert {[have_spec nova]}
 
 set flavor   "win7_64_raw"
 set vm_ram   "1280M"
@@ -18,7 +18,7 @@ set use_overlay_from_disk 0
 set use_serial 0
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox5_win7_64_share.run b/repos/ports/run/vbox5_win7_64_share.run
index 2c7a4a718a..3e0725bef8 100644
--- a/repos/ports/run/vbox5_win7_64_share.run
+++ b/repos/ports/run/vbox5_win7_64_share.run
@@ -1,5 +1,5 @@
-assert_spec x86_64
-assert_spec nova
+assert {[have_spec x86_64]}
+assert {[have_spec nova]}
 
 set flavor   "win7_64"
 set vm_ram   "1280M"
@@ -16,7 +16,7 @@ set use_rumpfs 1
 set use_serial 0
 set use_check_result 1
 
-set use_usb [expr ![get_cmd_switch --autopilot]]
+set use_usb [expr ![have_cmd_arg --autopilot]]
 set use_ps2 1
 
 set use_vms 1
diff --git a/repos/ports/run/vbox6_genode_usb_hid_raw.run b/repos/ports/run/vbox6_genode_usb_hid_raw.run
index 518b5f95a6..c5186b5855 100644
--- a/repos/ports/run/vbox6_genode_usb_hid_raw.run
+++ b/repos/ports/run/vbox6_genode_usb_hid_raw.run
@@ -8,10 +8,9 @@
 # Note: the USB device(s) to be passed through must be included in the whitelist.
 #
 
-if { [have_include "power_on/qemu"] || ![have_spec nova] || ![have_spec x86_64]} {
-	puts "Run script is only supported on 64-bit NOVA on real hardware"
-	exit 0
-}
+assert {[have_spec x86_64]}
+assert {[have_spec nova]}
+assert {![have_include power_on/qemu]}
 
 create_boot_directory
 import_from_depot [depot_user]/src/[base_src] \
@@ -184,7 +183,7 @@ global specs
 global repositories
 
 set depot_auto_update ""
-if {[get_cmd_switch --depot-auto-update]} {
+if {[have_cmd_arg --depot-auto-update]} {
 	set depot_auto_update "--depot-auto-update"
 }
 
@@ -212,7 +211,7 @@ append boot_components { usb_hid_raw.iso vbox6_genode_usb_hid_raw.vbox }
 
 build_boot_image $boot_components
 
-if { ![get_cmd_switch --autopilot] } { run_genode_until forever }
+if { ![have_cmd_arg --autopilot] } { run_genode_until forever }
 
 # autopilot test
 
diff --git a/repos/ports/run/vbox_share.inc b/repos/ports/run/vbox_share.inc
index cde1b72ffd..17d0afe734 100644
--- a/repos/ports/run/vbox_share.inc
+++ b/repos/ports/run/vbox_share.inc
@@ -57,16 +57,10 @@
 # beforehand. test.bat contains the actual instructions to be performed by
 # the VM - for this script to copy the test.bin file from D: to E:.
 
-if {[have_include "power_on/qemu"]} {
-	puts "\nRun script does not support Qemu.\n"
-	exit 0
-}
+assert {![have_include power_on/qemu]}
 
 # Tested for nova
-if {![have_spec nova]} {
-	puts "Platform is unsupported."
-	exit 0
-}
+assert {[have_spec nova]}
 
 set virtualbox_binary "virtualbox-rem"
 if {[have_spec nova]} { set virtualbox_binary "virtualbox-nova" }
diff --git a/repos/ports/run/vbox_win.inc b/repos/ports/run/vbox_win.inc
index 04a417684b..ea6c0917d0 100644
--- a/repos/ports/run/vbox_win.inc
+++ b/repos/ports/run/vbox_win.inc
@@ -1,14 +1,6 @@
-assert_spec x86
-
-if {(![have_spec nova] && ![have_spec foc])} {
-	puts "Platform is unsupported."
-	exit 0
-}
-
-if {[have_include "power_on/qemu"]} {
-	puts "\nRun script does not support Qemu.\n"
-	exit 0
-}
+assert {[have_spec x86]}
+assert {[have_spec nova] || [have_spec foc]}
+assert {![have_include power_on/qemu]}
 
 if {[expr !$use_rumpfs && $use_vms > 1] } {
 	puts "\nConfiguration bug - have only one raw block partition.\n"
diff --git a/repos/ports/run/verify.run b/repos/ports/run/verify.run
index b92a6aaa36..93f565c839 100644
--- a/repos/ports/run/verify.run
+++ b/repos/ports/run/verify.run
@@ -1,6 +1,6 @@
-if {[get_cmd_switch --autopilot] && [have_board virt_qemu_riscv]} {
-	puts "Autopilot mode is not supported on this platform."
-	exit 0
+if {[have_cmd_arg --autopilot]} {
+	assert {![have_board virt_qemu_riscv]} \
+		"Autopilot mode is not supported on this platform."
 }
 
 create_boot_directory
diff --git a/repos/ports/run/virtualbox.run b/repos/ports/run/virtualbox.run
index e50037da7e..433362afc9 100644
--- a/repos/ports/run/virtualbox.run
+++ b/repos/ports/run/virtualbox.run
@@ -1,4 +1,4 @@
-assert_spec nova
+assert {[have_spec nova]}
 
 set use_net 0
 set use_usb_qemu 0
diff --git a/repos/ports/run/virtualbox6.run b/repos/ports/run/virtualbox6.run
index f7be2deec6..d0b854c48b 100644
--- a/repos/ports/run/virtualbox6.run
+++ b/repos/ports/run/virtualbox6.run
@@ -1,4 +1,4 @@
-assert_spec x86_64
+assert {[have_spec x86_64]}
 
 set use_net 0
 set use_overlay 0
diff --git a/repos/ports/run/virtualbox_auto.inc b/repos/ports/run/virtualbox_auto.inc
index f76838ce84..25abfa63f8 100644
--- a/repos/ports/run/virtualbox_auto.inc
+++ b/repos/ports/run/virtualbox_auto.inc
@@ -1,18 +1,11 @@
-assert_spec x86
+assert {[have_spec x86]}
+assert {[have_spec nova] || [have_spec foc]}
 
-if {(![have_spec nova] && ![have_spec foc])} {
-	puts "Platform is unsupported."
-	exit 0
-}
+assert {![have_include power_on/qemu]}
 
-if {[have_include "power_on/qemu"]} {
-	puts "\nRun script does not support Qemu.\n"
-	exit
-}
-
-if { [get_cmd_switch --autopilot] && [have_spec x86_32] } {
-	puts "Run script does not support autopilot mode on 32 bit"
-	exit 0
+if {[have_cmd_arg --autopilot]} {
+	assert {![have_spec x86_32]} \
+		"Autopilot mode is not supported on this platform."
 }
 
 if {[have_spec nova]} {
diff --git a/repos/ports/run/vm_stress_vbox5-debian32.run b/repos/ports/run/vm_stress_vbox5-debian32.run
index ba41d5d9e1..908a58e4fd 100644
--- a/repos/ports/run/vm_stress_vbox5-debian32.run
+++ b/repos/ports/run/vm_stress_vbox5-debian32.run
@@ -2,8 +2,8 @@
 # Debian 32bit VM cloning Genode git sources, preparing and building pieces
 #
 
-assert_spec x86
-assert_spec nova
+assert {[have_spec x86]}
+assert {[have_spec nova]}
 
 set flavor   "stress_32"
 set vm_ram   "1280M"
diff --git a/repos/ports/run/vm_stress_vbox5-debian64.run b/repos/ports/run/vm_stress_vbox5-debian64.run
index 077c668cc2..30b739d443 100644
--- a/repos/ports/run/vm_stress_vbox5-debian64.run
+++ b/repos/ports/run/vm_stress_vbox5-debian64.run
@@ -2,8 +2,8 @@
 # Debian 64bit VM cloning Genode git sources, preparing and building pieces
 #
 
-assert_spec x86
-assert_spec nova
+assert {[have_spec x86]}
+assert {[have_spec nova]}
 
 set flavor   "stress_64"
 set vm_ram   "1280M"
diff --git a/repos/ports/run/vmm_vm_stress.inc b/repos/ports/run/vmm_vm_stress.inc
index c7d6ad162f..0b39f7d454 100644
--- a/repos/ports/run/vmm_vm_stress.inc
+++ b/repos/ports/run/vmm_vm_stress.inc
@@ -1,9 +1,10 @@
 #!/usr/bin/expect
 
-set current_date [clock format [clock seconds] -format %a]
-if {[get_cmd_switch --autopilot] && $current_date != "Sat" && $current_date != "Sun" } {
-	puts "\n Run script is not supported on this platform today. \n";
-	exit 0
+if {[have_cmd_arg --autopilot]} {
+	set current_date [clock format [clock seconds] -format %a]
+	assert {$current_date == "Sat" || $current_date == "Sun"} \
+		"Autopilot mode is not supported on this platform today."
+	}
 }
 
 run_genode_until $match_boot_string 40