diff --git a/jeannie b/jeannie
index 08e94ae..e22fcd6 100755
--- a/jeannie
+++ b/jeannie
@@ -1051,6 +1051,26 @@ echo 'Pimox VM ${vmid} guest-agent network-get-interfaces:'
 sudo '${qm_bin}' guest cmd '${vmid}' network-get-interfaces" >&2 || true
 }
 
+pimox_guest_exec_exitcode() {
+    local guest_exec_json="$1"
+
+    GUEST_EXEC_JSON="${guest_exec_json}" python3 - <<'PY'
+import json
+import os
+import sys
+
+try:
+    document = json.loads(os.environ.get("GUEST_EXEC_JSON", ""))
+except Exception:
+    sys.exit(2)
+
+try:
+    print(int(document.get("exitcode", 1)))
+except Exception:
+    sys.exit(2)
+PY
+}
+
 wait_for_pimox_guest_ssh() {
     local host="$1"
     local user="$2"
@@ -1214,6 +1234,7 @@ configure_pimox_worker_guest_network() {
     local script
     local encoded_script
     local network_output
+    local network_exitcode
     local worker_address
     local lan_probe_host="${LAB_PIMOX_WORKER_LAN_PROBE_HOST:-${LAB_DEBIAN_LAN_IP:-}}"
     local require_lan_probe="${LAB_PIMOX_WORKER_REQUIRE_LAN_PROBE:-true}"
@@ -1308,7 +1329,14 @@ EOF
     while ((SECONDS < deadline)); do
         if network_output="$(pimox_ssh "${pimox_host}" "${pimox_user}" "${pimox_key}" "sudo '${qm_bin}' guest exec '${vmid}' -- bash -lc \"printf '%s' '${encoded_script}' | base64 -d | sudo bash\"" 2>&1)"; then
             printf '%s\n' "${network_output}" | sed 's/^/    guest-network: /'
-            return 0
+            if network_exitcode="$(pimox_guest_exec_exitcode "${network_output}")" && [[ "${network_exitcode}" == "0" ]]; then
+                return 0
+            fi
+            echo "Static guest network validation failed inside Pimox VM ${vmid}." >&2
+            if [[ -n "${network_exitcode:-}" ]]; then
+                echo "Guest exit code: ${network_exitcode}" >&2
+            fi
+            return 1
         fi
         sleep 5
     done
diff --git a/tests/jeannie-unit b/tests/jeannie-unit
index ea4e634..2c4f73a 100755
--- a/tests/jeannie-unit
+++ b/tests/jeannie-unit
@@ -330,6 +330,12 @@ test_pimox_worker_static_ip_selection() {
     fi
 }
 
+test_pimox_guest_exec_exitcode_parser() {
+    assert_eq "pimox guest exec parses success exitcode" "0" "$(pimox_guest_exec_exitcode '{"exitcode":0,"exited":1}')"
+    assert_eq "pimox guest exec parses failed exitcode" "1" "$(pimox_guest_exec_exitcode '{"exitcode":1,"exited":1}')"
+    assert_command_failure_contains "pimox guest exec rejects invalid JSON" "" pimox_guest_exec_exitcode 'not json'
+}
+
 test_pimox_worker_count_detects_generated_topology
 test_configured_worker_count_cannot_hide_existing_workers
 test_configured_worker_count_can_expand_target_set
@@ -343,6 +349,7 @@ test_inventory_validator_accepts_current_inventory
 test_inventory_validator_rejects_ip_drift
 test_heal_cooldown_escalates_to_diagnostics
 test_pimox_worker_static_ip_selection
+test_pimox_guest_exec_exitcode_parser
 
 if ((FAILURES > 0)); then
     printf '\n%s unit test(s) failed.\n' "${FAILURES}" >&2