messages: DoorbellPress is sent with the empty context of its page

proactiveEvent() built every proactive event without a context, so doorbellPress() and
device.raise(DoorbellEventSource, "DoorbellPress") left out the "context": {} that the example of
alexa-doorbelleventsource.html has. The Event of Alexa.SimpleEventSource is printed without one, so
the event descriptor says which it is (emptyContext) and raise() passes it on to the builder.

A raised DoorbellPress is now { event, context: {} }, 13 bytes longer; the Event of a button is
unchanged. The tests compare the keys and the context of the built message with the fixture of the
page, for the builder, the descriptor and raise(). 267 tests pass.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

dist/cjs/device/Device.js

@@ -181,6 +181,7 @@ class Device extends events_1.EventEmitter {
             instance,
             payloadVersion: event.payloadVersion ?? capability.descriptor.version,
             payload: checked,
+            emptyContext: event.emptyContext,
         });
         const bytes = Buffer.byteLength(JSON.stringify(message));
         if (bytes > topics.EVENT_BYTES)

dist/cjs/messages/build.js

@@ -113,7 +113,11 @@ function sceneEvent(fields) {
         context: {},
     };
 }
-/** An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. */
+/**
+ * An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. The
+ * pages differ on the context, so the caller says which it is: DoorbellPress is printed with an empty one
+ * (alexa-doorbelleventsource.html), the Event of Alexa.SimpleEventSource without.
+ */
 function proactiveEvent(fields) {
     const { namespace, name, instance, messageId, payloadVersion, payload } = fields;
     return {
@@ -122,13 +126,16 @@ function proactiveEvent(fields) {
             endpoint: { endpointId: fields.endpointId },
             payload,
         },
+        ...(fields.emptyContext ? { context: {} } : {}),
     };
 }
 /** Somebody rang (alexa-doorbelleventsource.html). */
 function doorbellPress(fields) {
     const { endpointId, messageId } = fields;
     const payload = { cause: { type: fields.cause ?? "PHYSICAL_INTERACTION" }, timestamp: (0, property_js_1.isoTime)(fields.timestamp) };
-    return proactiveEvent({ endpointId, messageId, namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", payload });
+    return proactiveEvent({
+        endpointId, messageId, namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", payload, emptyContext: true,
+    });
 }
 /** An event of a button or a sensor that routines start on (alexa-simpleeventsource.html). */
 function simpleEvent(fields) {

dist/cjs/registry/interfaces/DoorbellEventSource.js

@@ -18,7 +18,7 @@ exports.DoorbellEventSource = (0, types_js_1.defineInterface)({
     properties: {},
     directives: {},
     events: {
-        DoorbellPress: { name: "DoorbellPress", payload: (0, events_js_1.happened)("PHYSICAL_INTERACTION"), topic: "proactive" },
+        DoorbellPress: { name: "DoorbellPress", payload: (0, events_js_1.happened)("PHYSICAL_INTERACTION"), topic: "proactive", emptyContext: true },
     },
     // The capability is the announcement that the endpoint raises the event: proactivelyReported whatever was declared
     discovery: () => ({ properties: false, topLevel: { proactivelyReported: true } }),

dist/esm/device/Device.js

@@ -146,6 +146,7 @@ class Device extends EventEmitter {
             instance,
             payloadVersion: event.payloadVersion ?? capability.descriptor.version,
             payload: checked,
+            emptyContext: event.emptyContext,
         });
         const bytes = Buffer.byteLength(JSON.stringify(message));
         if (bytes > topics.EVENT_BYTES)

dist/esm/messages/build.d.ts

@@ -88,8 +88,14 @@ export interface ProactiveEventFields extends Envelope {
     /** Default: "3". */
     payloadVersion?: string;
     payload: Record<string, unknown>;
+    /** true: the message has "context": {}, as the page of the event prints it. Default: no context. */
+    emptyContext?: boolean;
 }
-/** An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. */
+/**
+ * An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. The
+ * pages differ on the context, so the caller says which it is: DoorbellPress is printed with an empty one
+ * (alexa-doorbelleventsource.html), the Event of Alexa.SimpleEventSource without.
+ */
 export declare function proactiveEvent(fields: ProactiveEventFields): ProactiveEventMessage;
 export interface DoorbellPressFields extends Envelope {
     /** Default: "PHYSICAL_INTERACTION", somebody pressed the button. */

dist/esm/messages/build.js

@@ -99,7 +99,11 @@ export function sceneEvent(fields) {
         context: {},
     };
 }
-/** An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. */
+/**
+ * An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. The
+ * pages differ on the context, so the caller says which it is: DoorbellPress is printed with an empty one
+ * (alexa-doorbelleventsource.html), the Event of Alexa.SimpleEventSource without.
+ */
 export function proactiveEvent(fields) {
     const { namespace, name, instance, messageId, payloadVersion, payload } = fields;
     return {
@@ -108,13 +112,16 @@ export function proactiveEvent(fields) {
             endpoint: { endpointId: fields.endpointId },
             payload,
         },
+        ...(fields.emptyContext ? { context: {} } : {}),
     };
 }
 /** Somebody rang (alexa-doorbelleventsource.html). */
 export function doorbellPress(fields) {
     const { endpointId, messageId } = fields;
     const payload = { cause: { type: fields.cause ?? "PHYSICAL_INTERACTION" }, timestamp: isoTime(fields.timestamp) };
-    return proactiveEvent({ endpointId, messageId, namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", payload });
+    return proactiveEvent({
+        endpointId, messageId, namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", payload, emptyContext: true,
+    });
 }
 /** An event of a button or a sensor that routines start on (alexa-simpleeventsource.html). */
 export function simpleEvent(fields) {

dist/esm/messages/types.d.ts

@@ -73,4 +73,6 @@ export interface SceneEventMessage {
 /** An event a device raises by itself: DoorbellPress, the Event of Alexa.SimpleEventSource. */
 export interface ProactiveEventMessage {
     event: Event;
+    /** Only with an event whose page prints it: DoorbellPress has an empty one, the Event of a button has none. */
+    context?: {};
 }

dist/esm/registry/interfaces/DoorbellEventSource.js

@@ -15,7 +15,7 @@ export const DoorbellEventSource = defineInterface({
     properties: {},
     directives: {},
     events: {
-        DoorbellPress: { name: "DoorbellPress", payload: happened("PHYSICAL_INTERACTION"), topic: "proactive" },
+        DoorbellPress: { name: "DoorbellPress", payload: happened("PHYSICAL_INTERACTION"), topic: "proactive", emptyContext: true },
     },
     // The capability is the announcement that the endpoint raises the event: proactivelyReported whatever was declared
     discovery: () => ({ properties: false, topLevel: { proactivelyReported: true } }),

dist/esm/registry/types.d.ts

@@ -66,6 +66,8 @@ export interface EventDescriptor {
     payload: Schema<any>;
     /** response: the answer to a directive. proactive: sent without one. */
     topic: "response" | "proactive";
+    /** A proactive event that the page prints with "context": {}, DoorbellPress. Default: sent without a context. */
+    emptyContext?: boolean;
 }
 /** What an interface adds to the capability object in discovery, next to the fields every capability has. */
 export interface CapabilityExtras {

dist/types/messages/build.d.ts

@@ -88,8 +88,14 @@ export interface ProactiveEventFields extends Envelope {
     /** Default: "3". */
     payloadVersion?: string;
     payload: Record<string, unknown>;
+    /** true: the message has "context": {}, as the page of the event prints it. Default: no context. */
+    emptyContext?: boolean;
 }
-/** An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. */
+/**
+ * An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. The
+ * pages differ on the context, so the caller says which it is: DoorbellPress is printed with an empty one
+ * (alexa-doorbelleventsource.html), the Event of Alexa.SimpleEventSource without.
+ */
 export declare function proactiveEvent(fields: ProactiveEventFields): ProactiveEventMessage;
 export interface DoorbellPressFields extends Envelope {
     /** Default: "PHYSICAL_INTERACTION", somebody pressed the button. */

dist/types/messages/types.d.ts

@@ -73,4 +73,6 @@ export interface SceneEventMessage {
 /** An event a device raises by itself: DoorbellPress, the Event of Alexa.SimpleEventSource. */
 export interface ProactiveEventMessage {
     event: Event;
+    /** Only with an event whose page prints it: DoorbellPress has an empty one, the Event of a button has none. */
+    context?: {};
 }

dist/types/registry/types.d.ts

@@ -66,6 +66,8 @@ export interface EventDescriptor {
     payload: Schema<any>;
     /** response: the answer to a directive. proactive: sent without one. */
     topic: "response" | "proactive";
+    /** A proactive event that the page prints with "context": {}, DoorbellPress. Default: sent without a context. */
+    emptyContext?: boolean;
 }
 /** What an interface adds to the capability object in discovery, next to the fields every capability has. */
 export interface CapabilityExtras {

src/device/Device.ts

@@ -228,6 +228,7 @@ class Device extends EventEmitter {
       instance,
       payloadVersion: event.payloadVersion ?? capability.descriptor.version,
       payload: checked,
+      emptyContext: event.emptyContext,
     });
     const bytes = Buffer.byteLength(JSON.stringify(message));
     if (bytes > topics.EVENT_BYTES) return refuse(`it is ${bytes} bytes as JSON, Alex2MQTT takes ${topics.EVENT_BYTES}`);

src/messages/build.ts

@@ -182,9 +182,15 @@ export interface ProactiveEventFields extends Envelope {
   /** Default: "3". */
   payloadVersion?: string;
   payload: Record<string, unknown>;
+  /** true: the message has "context": {}, as the page of the event prints it. Default: no context. */
+  emptyContext?: boolean;
 }
 
-/** An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. */
+/**
+ * An event a device raises by itself, of any interface. The header has no correlationToken: nobody asked. The
+ * pages differ on the context, so the caller says which it is: DoorbellPress is printed with an empty one
+ * (alexa-doorbelleventsource.html), the Event of Alexa.SimpleEventSource without.
+ */
 export function proactiveEvent(fields: ProactiveEventFields): ProactiveEventMessage {
   const { namespace, name, instance, messageId, payloadVersion, payload } = fields;
   return {
@@ -193,6 +199,7 @@ export function proactiveEvent(fields: ProactiveEventFields): ProactiveEventMess
       endpoint: { endpointId: fields.endpointId },
       payload,
     },
+    ...(fields.emptyContext ? { context: {} } : {}),
   };
 }
 
@@ -207,7 +214,9 @@ export interface DoorbellPressFields extends Envelope {
 export function doorbellPress(fields: DoorbellPressFields): ProactiveEventMessage {
   const { endpointId, messageId } = fields;
   const payload = { cause: { type: fields.cause ?? "PHYSICAL_INTERACTION" }, timestamp: isoTime(fields.timestamp) };
-  return proactiveEvent({ endpointId, messageId, namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", payload });
+  return proactiveEvent({
+    endpointId, messageId, namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", payload, emptyContext: true,
+  });
 }
 
 export interface SimpleEventFields extends Envelope {

src/messages/types.ts

@@ -70,4 +70,6 @@ export interface SceneEventMessage {
 /** An event a device raises by itself: DoorbellPress, the Event of Alexa.SimpleEventSource. */
 export interface ProactiveEventMessage {
   event: Event;
+  /** Only with an event whose page prints it: DoorbellPress has an empty one, the Event of a button has none. */
+  context?: {};
 }

src/registry/interfaces/DoorbellEventSource.ts

@@ -16,7 +16,7 @@ export const DoorbellEventSource = defineInterface({
   properties: {},
   directives: {},
   events: {
-    DoorbellPress: { name: "DoorbellPress", payload: happened("PHYSICAL_INTERACTION"), topic: "proactive" },
+    DoorbellPress: { name: "DoorbellPress", payload: happened("PHYSICAL_INTERACTION"), topic: "proactive", emptyContext: true },
   },
   // The capability is the announcement that the endpoint raises the event: proactivelyReported whatever was declared
   discovery: () => ({ properties: false, topLevel: { proactivelyReported: true } }),

src/registry/types.ts

@@ -61,6 +61,8 @@ export interface EventDescriptor {
   payload: Schema<any>;
   /** response: the answer to a directive. proactive: sent without one. */
   topic: "response" | "proactive";
+  /** A proactive event that the page prints with "context": {}, DoorbellPress. Default: sent without a context. */
+  emptyContext?: boolean;
 }
 
 /** What an interface adds to the capability object in discovery, next to the fields every capability has. */

test/device/raise.test.js

@@ -30,7 +30,8 @@ const refused = (raise, problem) => assert.throws(raise, (err) => err instanceof
 
 test("raise() publishes the event on <root>/event, with the endpoint, a new messageId, the time and the usual cause", async () => {
   const { device, sent } = doorbell();
-  const printed = doc("alexa-doorbelleventsource", "DoorbellPress.event").event;
+  const example = doc("alexa-doorbelleventsource", "DoorbellPress.event");
+  const printed = example.event;
   const before = Date.now();
 
   assert.deepEqual(await device.raise(DoorbellEventSource, "DoorbellPress"), { ok: true, topic: "root/event" });
@@ -39,6 +40,10 @@ test("raise() publishes the event on <root>/event, with the endpoint, a new mess
 
   assert.equal(topics.event("root"), "root/event");
   assert.deepEqual(sent.published.map(({ topic }) => topic), ["root/event", "root/event", "root/event"]);
+  for (const { message } of sent.published) {
+    assert.deepEqual(Object.keys(message).sort(), Object.keys(example).sort());
+    assert.deepEqual(message.context, example.context);
+  }
   const [first, second, third] = sent.published.map(({ message }) => message.event);
   for (const event of [first, second, third]) {
     assert.deepEqual(event.endpoint, { endpointId: "door-1" });
@@ -62,7 +67,8 @@ test("raise() for an instance: the Event of a button has the instance in its hea
   remote.publisher = sent;
   const top = remote.add(SimpleEventSource, button("TopButton", ["SinglePush", "DoublePush"]));
   remote.add(SimpleEventSource, button("BottomButton", ["SinglePush"]));
-  const printed = doc("alexa-simpleeventsource", "Event.event").event;
+  const example = doc("alexa-simpleeventsource", "Event.event");
+  const printed = example.event;
 
   await remote.raise(SimpleEventSource, "Event", printed.payload, { instance: top.instance, messageId: "push-1" });
   assert.deepEqual(sent.published, [{
@@ -76,6 +82,7 @@ test("raise() for an instance: the Event of a button has the instance in its hea
     },
   }]);
   assert.equal(printed.header.payloadVersion, "1.0");
+  assert.deepEqual(Object.keys(sent.published[0].message), Object.keys(example));
 
   const raised = "remote-1: Alexa.SimpleEventSource.Event was not raised: ";
   assert.throws(() => remote.raise(SimpleEventSource, "Event", { id: "Button.SinglePush.1" }), {
@@ -117,7 +124,7 @@ test("raise() refuses an event the device has no capability for, and one that wo
   );
   refused(
     () => device.raise(DoorbellEventSource, "DoorbellPress", { picture: "x".repeat(topics.EVENT_BYTES) }),
-    `${was("Alexa.DoorbellEventSource.DoorbellPress")}it is 16296 bytes as JSON, Alex2MQTT takes 16000`
+    `${was("Alexa.DoorbellEventSource.DoorbellPress")}it is 16309 bytes as JSON, Alex2MQTT takes 16000`
   );
   assert.deepEqual(sent.published, []);
 });

test/messages/build.test.js

@@ -4,6 +4,7 @@
 const { test } = require("node:test");
 const assert = require("node:assert/strict");
 const { messages, MessageError } = require("alex2node");
+const { doc } = require("../helpers/fixtures.js");
 const { UUID_V4 } = require("../helpers/harness.js");
 
 const AT = "2026-09-28T10:00:00.000Z";
@@ -134,17 +135,21 @@ test("sceneEvent: ActivationStarted and DeactivationStarted with the cause and t
   assert.deepEqual(stopped.event.payload, { cause: { type: "APP_INTERACTION" }, timestamp: AT });
 });
 
-test("doorbellPress: an event without a correlationToken and without a context", () => {
-  assert.deepEqual(messages.doorbellPress({ endpointId: "door", messageId, timestamp: AT }), {
+test("doorbellPress: an event without a correlationToken, with the empty context of the page", () => {
+  const built = messages.doorbellPress({ endpointId: "door", messageId, timestamp: AT });
+  assert.deepEqual(built, {
     event: {
       header: { namespace: "Alexa.DoorbellEventSource", name: "DoorbellPress", messageId, payloadVersion: "3" },
       endpoint: { endpointId: "door" },
       payload: { cause: { type: "PHYSICAL_INTERACTION" }, timestamp: AT },
     },
+    context: {},
   });
+  assert.deepEqual(built.context, doc("alexa-doorbelleventsource", "DoorbellPress.event").context);
 });
 
-test("simpleEvent: the instance in the header, payloadVersion 1.0", () => {
+test("simpleEvent: the instance in the header, payloadVersion 1.0, no context as on the page", () => {
+  assert.equal("context" in doc("alexa-simpleeventsource", "Event.event"), false);
   assert.deepEqual(messages.simpleEvent({ endpointId: "button", instance: "Button.Front", id: "Button.SinglePush.1", messageId, timestamp: AT }), {
     event: {
       header: { namespace: "Alexa.SimpleEventSource", name: "Event", instance: "Button.Front", messageId, payloadVersion: "1.0" },

test/registry/events.test.js

@@ -30,9 +30,15 @@ test("the events of the pages fit the payload of their descriptor, and come back
     ["Alexa.WakeOnLANController", "alexa-wakeonlancontroller", "WakeUp", "response"],
   ];
   for (const [namespace, page, name, topic] of printed) {
-    const { header, payload } = doc(page, `${name}.event`).event;
+    const example = doc(page, `${name}.event`);
+    const { header, payload } = example.event;
     const descriptor = registry.get(namespace);
     const event = descriptor.events[name];
+    // raise() sends a context where the page prints one, and the pages print an empty one or none
+    if (topic === "proactive") {
+      assert.equal(event.emptyContext === true, "context" in example, name);
+      assert.deepEqual(example.context ?? {}, {}, name);
+    }
     assert.deepEqual([header.namespace, header.name, header.payloadVersion], [namespace, event.name, descriptor.version]);
     assert.equal(event.topic, topic, name);
     assert.equal("correlationToken" in header, topic === "response", name);