diff --git a/agent/BACKLOG.md b/agent/BACKLOG.md
index 68ecaba..b512ead 100644
--- a/agent/BACKLOG.md
+++ b/agent/BACKLOG.md
@@ -234,9 +234,6 @@ them as composable commands, not dead ends.
 - **Night-light geo mode**: lat/long auto sunset/sunrise (means wlsunset).
 - **Per-theme icon overrides** / more icon packs (ROADMAP § Icon themes).
 - **MIPI/IPU software-ISP camera** support (no-UVC machines).
-- **Doctor Waybar warning**: a self-gating bar indicator fed by
-  `nomarchy-doctor` (shipped 2026-07-04) — appears only when the sheet
-  has a ✖; click opens the sheet.
 - **Auto-timezone Waybar tooltip** showing the detected zone (optional).
 - **VPN exit-node richer display** (country/city) (optional).
 - **NixOS release bump → v2** `[human]`: deliberate, hand-edited, never
diff --git a/agent/HARDWARE-QUEUE.md b/agent/HARDWARE-QUEUE.md
index 2b81c6b..0d240d4 100644
--- a/agent/HARDWARE-QUEUE.md
+++ b/agent/HARDWARE-QUEUE.md
@@ -167,6 +167,12 @@ QA machine), the **T14s** (webcam case).
       (tooltips, fastfetch labels) is visible on summer-day +
       flexoki-light, kanagawa floats are lighter than the bg (upstream
       sumiInk4). Anything that reads worse than before → reopen 28b.
+- [ ] **Doctor bar tripwire (LATER item)** — with everything healthy
+      the bar shows nothing; `systemctl --user start doomed`-style
+      induced failure → within ~5 min a red  appears (tooltip lists
+      the ✖ lines), clicking opens the sheet in a terminal;
+      reset-failed → it disappears on the next poll. Also visible on
+      both summer bars.
 - [ ] **OCR region (LATER item)** — Tools › Capture › "OCR region →
       clipboard": select a region with visible text → toast reports
       the word count and `wl-paste` yields the text; Esc in slurp
diff --git a/agent/JOURNAL.md b/agent/JOURNAL.md
index ead5369..7a91c4e 100644
--- a/agent/JOURNAL.md
+++ b/agent/JOURNAL.md
@@ -17,6 +17,28 @@ Template:
 
 ---
 
+## 2026-07-05 — doctor bar tripwire (iteration #42, LATER item)
+- **Task:** LATER › doctor Waybar warning. Bullet deleted.
+- **Did:** nomarchy-doctor-status (named bin, PATH): silent exit 0
+  while the doctor is healthy or absent (self-gate), else JSON with
+  the first ✖ lines jq-escaped into the tooltip,  in @bad; click =
+  nomarchy-menu doctor (the sheet). custom/doctor added to the
+  generated bar (after battery, interval 300 — the check is real
+  work, this is a tripwire not a monitor) + CSS, AND both summer
+  whole-swaps (module list, jsonc block, CSS membership + @red rule)
+  per the parity rule.
+- **Verified:** V0; V1 — template-home builds, status bash -n, config
+  + CSS each carry the module, both summer jsonc still parse (jq)
+  with the block; FUNCTIONAL — self-gate silent, and a shimmed
+  failing doctor produces valid JSON (jq-verified: class bad, ✖
+  lines in tooltip). Live render → V3 queued.
+- **Pending:** V3. LATER remaining: wallpapers-artifact split
+  (deferred by decision), installer round 2 [big], boot-from-
+  snapshot, night-light geo, icon overrides, MIPI camera [hw],
+  auto-timezone tooltip, VPN richer display, release bump [human].
+- **Next suggestion:** auto-timezone Waybar tooltip (small) — or a
+  QA sweep; the meatier LATER items deserve a fresh session.
+
 ## 2026-07-05 — OCR screenshot-to-text (iteration #41, LATER item)
 - **Task:** LATER › OCR (NEXT is fully human/event-gated, so LATER is
   in play per LOOP.md). Bullet deleted.
diff --git a/modules/home/waybar.nix b/modules/home/waybar.nix
index 6676aa5..aa5c130 100644
--- a/modules/home/waybar.nix
+++ b/modules/home/waybar.nix
@@ -95,6 +95,18 @@ let
     printf '{"text":"󰦝","tooltip":"VPN active (click to manage)","class":"on"}\n'
   '';
 
+  # Health warning — self-gates: prints nothing while nomarchy-doctor
+  # exits 0, so the module only appears when the sheet has a ✖ (the
+  # same self-hide discipline as vpn/nightlight/updates). The tooltip
+  # carries the first failing lines; click opens the full sheet.
+  doctorStatus = pkgs.writeShellScriptBin "nomarchy-doctor-status" ''
+    command -v nomarchy-doctor >/dev/null 2>&1 || exit 0
+    out=$(nomarchy-doctor 2>/dev/null) && exit 0
+    tip=$(printf '%s\n' "$out" | grep '✖' | head -5 \
+      | ${pkgs.jq}/bin/jq -Rs 'rtrimstr("\n") + "\n(click for the full sheet)"')
+    printf '{"text":"","tooltip":%s,"class":"bad"}\n' "$tip"
+  '';
+
   # Per-theme override probe.
   assetDir = config.nomarchy.themesDir + "/${t.slug}";
   styleOverride = assetDir + "/waybar.css";
@@ -123,7 +135,7 @@ let
     modules-center = [ "clock" ];
     modules-right = [ "custom/recording" "idle_inhibitor" "tray" "custom/vpn" "pulseaudio" "cpu" "memory" "custom/powerprofile" "custom/nightlight" ]
       ++ lib.optional showLanguage "hyprland/language"
-      ++ [ "battery" "custom/updates" "custom/notification" ];
+      ++ [ "battery" "custom/doctor" "custom/updates" "custom/notification" ];
 
     "hyprland/workspaces" = {
       format = "{icon}";
@@ -197,6 +209,15 @@ let
       on-click = "nomarchy-vpn";
     };
 
+    # Health check is real work (systemctl/disk/git sweeps), so a long
+    # interval — this is a tripwire, not a monitor.
+    "custom/doctor" = {
+      exec = "nomarchy-doctor-status";
+      return-type = "json";
+      interval = 300;
+      on-click = "nomarchy-menu doctor";
+    };
+
     # Screen recording indicator. Self-gates: visible only while
     # nomarchy-record runs (status prints nothing otherwise), and the
     # click IS the stop surface — the menu only starts recordings.
@@ -310,7 +331,7 @@ let
       font-weight: bold;
     }
 
-    #tray, #pulseaudio, #cpu, #memory, #custom-powerprofile, #custom-nightlight, #custom-updates, #custom-vpn, #custom-recording, #idle_inhibitor, #language, #battery, #custom-notification {
+    #tray, #pulseaudio, #cpu, #memory, #custom-powerprofile, #custom-nightlight, #custom-updates, #custom-vpn, #custom-recording, #idle_inhibitor, #language, #battery, #custom-doctor, #custom-notification {
       color: alpha(@text, 0.85);
       padding: 0 10px;
     }
@@ -337,6 +358,10 @@ let
     /* Updates pending → accent, to draw the eye. */
     #custom-updates.available { color: @accent; }
 
+    /* Doctor tripwire — only rendered when something is ✖, so it is
+       always the alert color. */
+    #custom-doctor { color: @bad; }
+
     /* The power-profile speedometer glyph renders small in its em box —
        size it up so it reads at a glance like the other indicators. */
     #custom-powerprofile { font-size: ${toString (t.fonts.size + 3)}pt; }
@@ -386,5 +411,5 @@ in
   # whole-swap themes' static waybar.jsonc can exec them by name — plus
   # the supervisor hyprland.nix exec-onces.
   home.packages = lib.optionals config.nomarchy.waybar.enable
-    [ waybarSupervisor powerProfileStatus powerProfileCycle vpnStatus ];
+    [ waybarSupervisor powerProfileStatus powerProfileCycle vpnStatus doctorStatus ];
 }
diff --git a/themes/summer-day/waybar.css b/themes/summer-day/waybar.css
index 80ea1a0..34e4eff 100755
--- a/themes/summer-day/waybar.css
+++ b/themes/summer-day/waybar.css
@@ -55,6 +55,7 @@ window#waybar {
 #custom-updates,
 #battery,
 #tray,
+#custom-doctor,
 #custom-notification,
 #custom-powermenu {
   background-color: @bg0;
@@ -127,3 +128,8 @@ window#waybar {
 #custom-recording.recording {
   color: @red;
 }
+
+/* Doctor tripwire: only rendered when something is broken. */
+#custom-doctor {
+  color: @red;
+}
diff --git a/themes/summer-day/waybar.jsonc b/themes/summer-day/waybar.jsonc
index 3c7c069..490dc61 100644
--- a/themes/summer-day/waybar.jsonc
+++ b/themes/summer-day/waybar.jsonc
@@ -11,7 +11,7 @@
 
   "modules-left": ["custom/launcher", "clock", "clock#date"],
   "modules-center": ["hyprland/workspaces"],
-  "modules-right": ["custom/recording", "idle_inhibitor", "pulseaudio", "custom/powerprofile", "custom/nightlight", "hyprland/language", "custom/updates", "battery", "tray", "custom/vpn", "custom/notification", "custom/powermenu"],
+  "modules-right": ["custom/recording", "idle_inhibitor", "pulseaudio", "custom/powerprofile", "custom/nightlight", "hyprland/language", "custom/updates", "battery", "tray", "custom/vpn", "custom/doctor", "custom/notification", "custom/powermenu"],
 
   "hyprland/workspaces": {
     "disable-scroll": true,
@@ -95,6 +95,13 @@
     "on-click": "nomarchy-record stop"
   },
 
+  "custom/doctor": {
+    "return-type": "json",
+    "interval": 300,
+    "exec": "nomarchy-doctor-status",
+    "on-click": "nomarchy-menu doctor"
+  },
+
   "custom/vpn": {
     "return-type": "json",
     "interval": 5,
diff --git a/themes/summer-night/waybar.css b/themes/summer-night/waybar.css
index bea7a80..1ba24c1 100644
--- a/themes/summer-night/waybar.css
+++ b/themes/summer-night/waybar.css
@@ -60,6 +60,7 @@ window#waybar {
 #custom-updates,
 #idle_inhibitor,
 #battery,
+#custom-doctor,
 #custom-notification,
 #custom-powermenu {
   background-color: @bg0;
@@ -139,3 +140,8 @@ window#waybar {
 #custom-recording.recording {
   color: @red;
 }
+
+/* Doctor tripwire: only rendered when something is broken. */
+#custom-doctor {
+  color: @red;
+}
diff --git a/themes/summer-night/waybar.jsonc b/themes/summer-night/waybar.jsonc
index 56a4317..272a34c 100644
--- a/themes/summer-night/waybar.jsonc
+++ b/themes/summer-night/waybar.jsonc
@@ -11,7 +11,7 @@
 
   "modules-left": ["custom/nomarchy", "clock", "clock#date"],
   "modules-center": ["hyprland/workspaces"],
-  "modules-right": ["custom/recording", "idle_inhibitor", "pulseaudio", "custom/powerprofile", "custom/nightlight", "hyprland/language", "custom/updates", "battery", "tray", "custom/vpn", "custom/notification", "custom/powermenu"],
+  "modules-right": ["custom/recording", "idle_inhibitor", "pulseaudio", "custom/powerprofile", "custom/nightlight", "hyprland/language", "custom/updates", "battery", "tray", "custom/vpn", "custom/doctor", "custom/notification", "custom/powermenu"],
 
   "hyprland/workspaces": {
     "disable-scroll": true,
@@ -94,6 +94,13 @@
     "on-click": "nomarchy-record stop"
   },
 
+  "custom/doctor": {
+    "return-type": "json",
+    "interval": 300,
+    "exec": "nomarchy-doctor-status",
+    "on-click": "nomarchy-menu doctor"
+  },
+
   "custom/vpn": {
     "return-type": "json",
     "interval": 5,