diff --git a/seats/node-engine/fixtures/events.json b/seats/node-engine/fixtures/events.json
index 657566e..56731bd 100644
--- a/seats/node-engine/fixtures/events.json
+++ b/seats/node-engine/fixtures/events.json
@@ -92,6 +92,34 @@
       "at": "2026-11-09T20:01:00Z"
     }
   },
+  {
+    "name": "running says the build that runs is healthy",
+    "of": "event:running",
+    "subject": "mesh.seat.node-engine.event.running.ace.nats",
+    "given": {
+      "v": 1,
+      "node": "ace",
+      "module": "nats",
+      "fingerprint": "src2:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+      "manifest": "sha256:cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc",
+      "healthy": true,
+      "at": "2026-11-11T09:00:00Z"
+    }
+  },
+  {
+    "name": "running says the build that runs turned unhealthy, still running",
+    "of": "event:running",
+    "subject": "mesh.seat.node-engine.event.running.ace.nats",
+    "given": {
+      "v": 1,
+      "node": "ace",
+      "module": "nats",
+      "fingerprint": "src2:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+      "manifest": "sha256:cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc",
+      "healthy": false,
+      "at": "2026-11-11T09:05:00Z"
+    }
+  },
   {
     "name": "running says a module stopped on the node, with no fingerprint",
     "of": "event:running",
diff --git a/seats/node-engine/seat.json b/seats/node-engine/seat.json
index ab45d89..89352fa 100644
--- a/seats/node-engine/seat.json
+++ b/seats/node-engine/seat.json
@@ -2883,7 +2883,7 @@
     },
     "Running": {
       "type": "object",
-      "description": "a module running healthy on a node at a build: what the node-engines of other nodes and the grants part decide a seat's pass from (ADR 0660 §2), kept last per subject with no age limit",
+      "description": "a module's build running on a node, and its health: what the node-engines of other nodes and the grants part decide a seat's pass from (ADR 0660 §2), and the assigner reads a provider's and a canary's health and a put's end from (design 47 G 520); said again on the same subject each time healthy changes and for every module the have holds at the engine's start, kept last per subject with no age limit",
       "properties": {
         "v": {
           "type": "integer",
@@ -2905,14 +2905,21 @@
           "type": "string",
           "description": "the digest of that build's manifest, the indexer's manifest of it, read by digest from the catalog half"
         },
+        "healthy": {
+          "type": [
+            "boolean",
+            "null"
+          ],
+          "description": "the health of the build that runs, as the node-engine's have holds it from the module's declared check (ADR 0240); a running with none, said by a node-engine of before design 47 G, reads as healthy (design 47 G 520). SeatsToPassOn reads none of it: an unhealthy holder still holds its seat"
+        },
         "at": {
           "type": "string",
-          "description": "when it was seen running healthy, RFC 3339",
+          "description": "when it was said, RFC 3339",
           "format": "date-time"
         },
         "stopped": {
           "type": "boolean",
-          "description": "true when the module no longer runs on the node: no fingerprint or manifest then (design 47 G 365, 404); mesh-sdk's SeatsToPassOn counts such a module as not running there"
+          "description": "true when the have no longer holds the module on the node, never for an unhealthy build: no fingerprint or manifest then (design 47 G 365, 404, 520); mesh-sdk's SeatsToPassOn counts such a module as not running there"
         }
       },
       "required": [