refactor(agent): register the rtk gauge in the typed analytics event map

Every analytics event in the app pairs its ANALYTICS_EVENTS constant
with a *Properties interface and an EventPropertyMap entry (that map
backs the renderer's typed track helper, and main-process events like
CLOUD_STREAM_DISCONNECTED register too). RTK savings gauge was the one
event missing both — add RtkSavingsGaugeProperties, the map entry, and
a satisfies check at the reporter's call site so the emitted bag cannot
drift from the declared shape.

Generated-By: PostHog Code
Task-Id: b86391cc-4634-4a2b-ae34-fe1f9c0626a0

Author: pauldambra

packages/core/src/usage/rtk-savings-reporter.ts

@@ -7,7 +7,10 @@ import {
   APP_LIFECYCLE_SERVICE,
   type IAppLifecycle,
 } from "@posthog/platform/app-lifecycle";
-import { ANALYTICS_EVENTS } from "@posthog/shared/analytics-events";
+import {
+  ANALYTICS_EVENTS,
+  type RtkSavingsGaugeProperties,
+} from "@posthog/shared/analytics-events";
 import { inject, injectable, postConstruct, preDestroy } from "inversify";
 import { RTK_SAVINGS_HOST, type RtkSavingsHost } from "./identifiers";
 
@@ -77,7 +80,7 @@ export class RtkSavingsReporter {
         cumulative_input_tokens: gauge.inputTokens,
         cumulative_output_tokens: gauge.outputTokens,
         cumulative_tokens_saved: gauge.tokensSaved,
-      });
+      } satisfies RtkSavingsGaugeProperties);
       this.logger.debug("Reported rtk savings gauge", { reading });
     } catch (error) {
       this.logger.debug("Failed to report rtk savings gauge", { error });

packages/shared/src/analytics-events.ts

@@ -275,6 +275,21 @@ export interface CloudStreamDisconnectedProperties {
   was_bootstrapping: boolean;
 }
 
+/**
+ * A gauge snapshot of rtk's cumulative machine-global savings counter,
+ * mirroring the cloud agent's `_posthog/rtk_savings` event shape. Consumers
+ * group by `counter_id` and difference readings (with an implicit 0 before a
+ * counter's first reading, and a value drop treated as a reset) — never sum
+ * event values, which would multiply-count re-reads of the shared counter.
+ */
+export interface RtkSavingsGaugeProperties {
+  counter_id: string;
+  cumulative_commands: number;
+  cumulative_input_tokens: number;
+  cumulative_output_tokens: number;
+  cumulative_tokens_saved: number;
+}
+
 // Permission events
 export interface PermissionRespondedProperties {
   task_id: string;
@@ -1136,9 +1151,7 @@ export const ANALYTICS_EVENTS = {
   SUBSCRIPTION_STARTED: "Subscription started",
   SUBSCRIPTION_CANCELLED: "Subscription cancelled",
 
-  // RTK output-compression telemetry. A gauge snapshot of rtk's cumulative
-  // machine-global savings counter: consumers group by counter_id and
-  // difference readings (never sum) — see RtkSavingsReporter in core.
+  // RTK output-compression telemetry — see RtkSavingsGaugeProperties.
   RTK_SAVINGS_GAUGE: "RTK savings gauge",
 
   // Project Bluebird (Channels) events
@@ -1292,6 +1305,9 @@ export type EventPropertyMap = {
   [ANALYTICS_EVENTS.SUBSCRIPTION_STARTED]: SubscriptionStartedProperties;
   [ANALYTICS_EVENTS.SUBSCRIPTION_CANCELLED]: SubscriptionCancelledProperties;
 
+  // RTK output-compression telemetry
+  [ANALYTICS_EVENTS.RTK_SAVINGS_GAUGE]: RtkSavingsGaugeProperties;
+
   // Project Bluebird (Channels) events
   [ANALYTICS_EVENTS.CHANNELS_SPACE_VIEWED]: ChannelsSpaceViewedProperties;
   [ANALYTICS_EVENTS.CHANNEL_ACTION]: ChannelActionProperties;