diff --git a/schema/envelope.json b/schema/envelope.json
index 97f3d8d..cf25ff3 100644
--- a/schema/envelope.json
+++ b/schema/envelope.json
@@ -2,7 +2,7 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://yukart/schema/envelope.json",
   "title": "Signal envelope",
-  "description": "Every decoded signal published on yukart/vehicle/* and yukart/gnss/*. Raw CAN uses the binary frame encoding instead.",
+  "description": "Every decoded signal published on yukart/vehicle/*, yukart/gnss/* and yukart/host/*. Raw CAN uses the binary frame encoding instead.",
   "type": "object",
   "required": [
     "timestamp",
diff --git a/schema/signals.json b/schema/signals.json
index dba3c5f..5d5ffee 100644
--- a/schema/signals.json
+++ b/schema/signals.json
@@ -1,5 +1,5 @@
 {
-  "$comment": "Single source for signal identity. Topic name and envelope unit are both derived from these entries and are never authored separately. source=obd2 is standardised; source=z27ag is reverse-engineered and lives in the DBC.",
+  "$comment": "Single source for signal identity. Topic name and envelope unit are both derived from these entries and are never authored separately. source=obd2 is standardised; source=z27ag is reverse-engineered and lives in the DBC. source=host is the Orin itself (orin-status), not the car.",
   "signals": {
     "engine_rpm": {
       "unit": "rpm",
@@ -90,6 +90,256 @@
         0,
         656
       ]
+    },
+    "orin_cpu_temp_c": {
+      "unit": "celsius",
+      "type": "number",
+      "source": "host",
+      "description": "Orin CPU cluster temperature",
+      "range": [
+        -40,
+        110
+      ]
+    },
+    "orin_gpu_temp_c": {
+      "unit": "celsius",
+      "type": "number",
+      "source": "host",
+      "description": "Orin GPU temperature",
+      "range": [
+        -40,
+        110
+      ]
+    },
+    "orin_soc_temp_c": {
+      "unit": "celsius",
+      "type": "number",
+      "source": "host",
+      "description": "Orin SoC temperature, hottest of its sensors",
+      "range": [
+        -40,
+        110
+      ]
+    },
+    "orin_tj_temp_c": {
+      "unit": "celsius",
+      "type": "number",
+      "source": "host",
+      "description": "Orin junction temperature: the hottest point on the die, which throttling acts on",
+      "range": [
+        -40,
+        110
+      ]
+    },
+    "orin_cpu_pct": {
+      "unit": "percent",
+      "type": "number",
+      "source": "host",
+      "description": "CPU utilisation, all cores",
+      "range": [
+        0,
+        100
+      ]
+    },
+    "orin_gpu_pct": {
+      "unit": "percent",
+      "type": "number",
+      "source": "host",
+      "description": "GPU utilisation",
+      "range": [
+        0,
+        100
+      ]
+    },
+    "orin_ram_used_mb": {
+      "unit": "MB",
+      "type": "number",
+      "source": "host",
+      "description": "Memory in use, CPU and GPU together (one shared pool): total minus available",
+      "range": [
+        0,
+        8192
+      ]
+    },
+    "orin_ram_used_pct": {
+      "unit": "percent",
+      "type": "number",
+      "source": "host",
+      "description": "Memory in use as a share of the total",
+      "range": [
+        0,
+        100
+      ]
+    },
+    "orin_swap_used_mb": {
+      "unit": "MB",
+      "type": "number",
+      "source": "host",
+      "description": "Swap in use",
+      "range": [
+        0,
+        16384
+      ]
+    },
+    "orin_power_w": {
+      "unit": "W",
+      "type": "number",
+      "source": "host",
+      "description": "Orin module input power (VDD_IN), from the onboard INA3221",
+      "range": [
+        0,
+        30
+      ]
+    },
+    "orin_fan_rpm": {
+      "unit": "rpm",
+      "type": "number",
+      "source": "host",
+      "description": "Cooling fan speed",
+      "range": [
+        0,
+        10000
+      ]
+    },
+    "net_wifi_up": {
+      "unit": "",
+      "type": "boolean",
+      "source": "host",
+      "description": "WiFi associated and up"
+    },
+    "net_wifi_signal_dbm": {
+      "unit": "dBm",
+      "type": "number",
+      "source": "host",
+      "description": "WiFi signal level",
+      "range": [
+        -100,
+        0
+      ]
+    },
+    "net_wifi_rx_kbps": {
+      "unit": "kbit/s",
+      "type": "number",
+      "source": "host",
+      "description": "WiFi receive rate (into the Orin)",
+      "range": [
+        0,
+        1000000
+      ]
+    },
+    "net_wifi_tx_kbps": {
+      "unit": "kbit/s",
+      "type": "number",
+      "source": "host",
+      "description": "WiFi transmit rate (out of the Orin)",
+      "range": [
+        0,
+        1000000
+      ]
+    },
+    "net_lte_state": {
+      "unit": "",
+      "type": "string",
+      "source": "host",
+      "description": "Modem state as ModemManager reports it (connected, registered, searching, disabled, …), or absent with no modem"
+    },
+    "net_lte_tech": {
+      "unit": "",
+      "type": "string",
+      "source": "host",
+      "description": "Access technology in use (lte, umts, …); empty when not registered"
+    },
+    "net_lte_signal_pct": {
+      "unit": "percent",
+      "type": "number",
+      "source": "host",
+      "description": "Modem signal quality",
+      "range": [
+        0,
+        100
+      ]
+    },
+    "net_lte_rx_kbps": {
+      "unit": "kbit/s",
+      "type": "number",
+      "source": "host",
+      "description": "LTE receive rate (into the Orin)",
+      "range": [
+        0,
+        150000
+      ]
+    },
+    "net_lte_tx_kbps": {
+      "unit": "kbit/s",
+      "type": "number",
+      "source": "host",
+      "description": "LTE transmit rate (out of the Orin)",
+      "range": [
+        0,
+        50000
+      ]
+    },
+    "net_tablet_up": {
+      "unit": "",
+      "type": "boolean",
+      "source": "host",
+      "description": "USB link to the tablet has carrier"
+    },
+    "net_tablet_rx_kbps": {
+      "unit": "kbit/s",
+      "type": "number",
+      "source": "host",
+      "description": "USB tablet link, tablet to Orin",
+      "range": [
+        0,
+        480000
+      ]
+    },
+    "net_tablet_tx_kbps": {
+      "unit": "kbit/s",
+      "type": "number",
+      "source": "host",
+      "description": "USB tablet link, Orin to tablet",
+      "range": [
+        0,
+        480000
+      ]
+    },
+    "ups_battery_v": {
+      "unit": "V",
+      "type": "number",
+      "source": "host",
+      "description": "UPS battery pack voltage (3S Li-ion, 9.0–12.6 V)",
+      "range": [
+        0,
+        16
+      ]
+    },
+    "ups_current_a": {
+      "unit": "A",
+      "type": "number",
+      "source": "host",
+      "description": "UPS battery current: positive charging, negative discharging",
+      "range": [
+        -5,
+        5
+      ]
+    },
+    "ups_battery_pct": {
+      "unit": "percent",
+      "type": "number",
+      "source": "host",
+      "description": "UPS charge estimate from cell voltage, corrected for load. An estimate, steadiest at rest",
+      "range": [
+        0,
+        100
+      ]
+    },
+    "ups_state": {
+      "unit": "",
+      "type": "string",
+      "source": "host",
+      "description": "charging, discharging (running on battery) or idle (on input power, not charging)"
     }
   }
 }
diff --git a/schema/topics.json b/schema/topics.json
index a837a3b..7e5c61c 100644
--- a/schema/topics.json
+++ b/schema/topics.json
@@ -22,6 +22,13 @@
       "publisher": "gnss",
       "description": "value is an object: lat, lon, alt_m, speed_kph, heading_deg, fix, satellites."
     },
+    "yukart/host/<signal>": {
+      "payload": "envelope",
+      "retained": true,
+      "rate": "1/s",
+      "publisher": "orin-status",
+      "description": "The Orin itself: temperatures, load, memory, network links, UPS battery. One topic per signal, named exactly as in signals.json (source=host)."
+    },
     "yukart/system/<service>": {
       "payload": "json",
       "retained": true,