C6: the watchdogs seat declares presence's answer: with machine, that machine's online and since; without, the keys of the state presence (issue 1966, ADR 0596 §2, ADR 0668 §3; review round 3, finding 1)

The builder and the indexer ask whether a node's machine is heard through this verb instead of reading the watchman's state; regenerated with seatgen, whose -check names nothing new.

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

health-and-repair/go/seats/meshwatchdogs/contract.go

@@ -202,8 +202,31 @@ type PresenceInput struct {
 	Machine string `json:"machine,omitempty"`
 }
 
+// PresenceAnswerKeysItem is a type of the contract.
+type PresenceAnswerKeysItem struct {
+	// <node> or part.<part>.<instance>
+	Key string `json:"key"`
+	// the key's revision
+	Revision int64 `json:"revision,omitempty"`
+	// the key's value, online and its layout's version
+	Value map[string]any `json:"value"`
+}
+
 // PresenceAnswer is what presence answers.
-type PresenceAnswer = map[string]any
+type PresenceAnswer struct {
+	// without machine: how many keys the state holds
+	Holds int64 `json:"holds,omitempty"`
+	// without machine: each key of the state presence, <node> or part.<part>.<instance>, with its value
+	Keys []PresenceAnswerKeysItem `json:"keys,omitempty"`
+	// the machine asked, with machine
+	Machine string `json:"machine,omitempty"`
+	// with machine: whether the watchman hears the machine now; false for a machine it holds no word of
+	Online bool `json:"online,omitempty"`
+	// with machine: when its presence last changed, RFC 3339; empty for a machine the watchman holds no word of
+	Since string `json:"since,omitempty"`
+	// without machine: the state read, presence
+	State string `json:"state,omitempty"`
+}
 
 // DeadLettersInput is what dead-letters takes.
 type DeadLettersInput struct {

health-and-repair/seats/mesh-watchdogs/seat.json

@@ -43,7 +43,7 @@
     },
     {
       "name": "presence",
-      "description": "Every machine and tool runner the watchman sees connected, with its last word, and those it says silent; a machine that said it sleeps is shown as sleeping, not silent.",
+      "description": "Every machine and tool runner the watchman sees connected, with its last word, and those it says silent; a machine that said it sleeps is shown as sleeping, not silent. With machine, that machine's presence alone: whether the watchman hears it and since when.",
       "input": {
         "properties": {
           "machine": {
@@ -55,7 +55,54 @@
       },
       "answer": {
         "type": "object",
-        "description": "who is connected and who is silent"
+        "description": "with machine, that machine: online and since; without, every key of the state presence",
+        "properties": {
+          "machine": {
+            "type": "string",
+            "description": "the machine asked, with machine"
+          },
+          "online": {
+            "type": "boolean",
+            "description": "with machine: whether the watchman hears the machine now; false for a machine it holds no word of"
+          },
+          "since": {
+            "type": "string",
+            "description": "with machine: when its presence last changed, RFC 3339; empty for a machine the watchman holds no word of"
+          },
+          "state": {
+            "type": "string",
+            "description": "without machine: the state read, presence"
+          },
+          "holds": {
+            "type": "integer",
+            "description": "without machine: how many keys the state holds"
+          },
+          "keys": {
+            "type": "array",
+            "description": "without machine: each key of the state presence, <node> or part.<part>.<instance>, with its value",
+            "items": {
+              "type": "object",
+              "properties": {
+                "key": {
+                  "type": "string",
+                  "description": "<node> or part.<part>.<instance>"
+                },
+                "value": {
+                  "type": "object",
+                  "description": "the key's value, online and its layout's version"
+                },
+                "revision": {
+                  "type": "integer",
+                  "description": "the key's revision"
+                }
+              },
+              "required": [
+                "key",
+                "value"
+              ]
+            }
+          }
+        }
       }
     },
     {

health-and-repair/ts/seats/meshwatchdogs/src/index.ts

@@ -116,8 +116,30 @@ export interface PresenceInput {
   "machine"?: string;
 }
 
+export interface PresenceAnswerKeysItem {
+  /** <node> or part.<part>.<instance> */
+  "key": string;
+  /** the key's revision */
+  "revision"?: number;
+  /** the key's value, online and its layout's version */
+  "value": Record<string, unknown>;
+}
+
 /** is what presence answers. */
-export type PresenceAnswer = Record<string, unknown>;
+export interface PresenceAnswer {
+  /** without machine: how many keys the state holds */
+  "holds"?: number;
+  /** without machine: each key of the state presence, <node> or part.<part>.<instance>, with its value */
+  "keys"?: PresenceAnswerKeysItem[];
+  /** the machine asked, with machine */
+  "machine"?: string;
+  /** with machine: whether the watchman hears the machine now; false for a machine it holds no word of */
+  "online"?: boolean;
+  /** with machine: when its presence last changed, RFC 3339; empty for a machine the watchman holds no word of */
+  "since"?: string;
+  /** without machine: the state read, presence */
+  "state"?: string;
+}
 
 /** is what dead-letters takes. */
 export interface DeadLettersInput {